Seminar #79 from Online Seminars for Municipal Arborists
July - September 2018
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Trees in Hurricane Winds
By Mark A. Webber
The hurricane season in 2017 made headlines all over the world. Many of these storms were concentrated in the Atlantic Ocean Basin. The 2017 hurricane season was well above the 30-year average with the number of storms and became one of the 10 most active Atlantic seasons on record.
Hurricane Maria's Category 4 landfall on Puerto Rico was a worst-case event, and resulted with power being lost to more than 90% of the island, along with disrupted cell and water service. At least 51 people were killed by Maria in Puerto Rico and significant tree damage was also reported.
Hurricane Irma killed dozens of people and injured others. This record-breaking storm roared over the Dutch and French island of Sint Maarten (St. Martin) with reported winds topping at 185 miles (295 kilometers) per hour. According to the US National Hurricane Center, Irma was one of the strongest storms ever recorded in the Atlantic Ocean.
Background
Since 1988, I have been learning about tropical trees and plants and have annually visited St. Martin and San Juan, Puerto Rico. In February of 2018, approximately five months after the effects of these two major hurricanes I went back to the islands to witness what happened to the trees that I had been learning about. More so, what lessons could be learned for the future management and care of trees in the urban landscape. As part of my investigation, I compared photographs of the trees and plants from previous visits to the islands to the conditions I witnessed in 2018. In addition, I conducted interviews with people who were on the ground when these two weather events occurred.
St. Martin – Prior to Hurricane Irma
The island of St. Martin is made up of two political divisions and is 13 square miles (Britannica.com) in area. The east side of the island is French and is situated with the Atlantic Ocean on its eastern shore. The west side is Dutch and is situated with the Caribbean Sea on its western shore.
Prior to Hurricane Irma, the Dutch side had approximately 15 native trees species. Most of these trees were configured with the adaptive growth of large thick trunks and the scaffolding limbs that were typically at 60 to 90 degree trunk/branch angles. Those species include the gum tree (Bursera simaruba) ,redwood (Inga laurina), white frangepane (Plumeria alba), loblolly (Pisonia fragrans), devil's tree (Morisonia americana), locust tree (Hymenaea courbaril), tamarind (Tamarindus indica),white cedar (Tabebuia pallida) , e casha (Acacia spec.) black cherry (Randia aculeata), thornless West Indian cherry (Malpighia emarginata), mimosa (Leucaena leucocephala) and ficus species like Ficus urbaniana. Most trees on the island are shrub-like and the ground is often covered with a layer of cacti of the genus Opuntia.
The French side St. Martin in the areas along the seashore contained dense populations of mangrove trees. Mangroves have an important ecological niche to local ecosystems and are made up of three unique tree species (Rojer1997). They are red mangrove (Rhizophora mangle) black mangrove (Avicennia germinans), and white mangrove (Laguncularia racemosa).
Throughout the urbanized areas of both the Dutch and French sides, other plantings were made up of a mix of native and non-native species like palms, cactus, fruit bearing trees and tropical plants from other regions of the world.
St. Martin – Post Hurricane Irma
Weather reports stated that St. Martin sustained winds in excess of 185 miles per hour and photographs after the storm depict trees and debris was everywhere, and a number of buildings had collapsed. Additionally, eyewitness accounts described flooded conditions.
My investigation found the surrounding steep hillsides of the French side of St. Martin where Irma first breached were still brown when I observed them in February of 2018. These areas are where the hurricane winds had the most impact. These areas consisted of steep hillsides that were protected by topography contained vegetation that had been defoliated by the strong winds and were now re-growing. Additionally, very few trees situated on the Atlantic side of island survived unless they were sheltered by other trees, buildings or structures. In fact, whole groves of trees in some cases were destroyed without any survivors. More compelling is the complete death of the mangroves along the shoreline and coconut palms that were pulled out the soil by the forces of Irma. Along approximately 15 miles of coastline, I only observed 20 – 25 trees that remained. This same section of coastline a year ago contained thousands of trees. The trees that survived Irma's wrath in most cases were cabbage palms (Sabal palmetto). If trees or small plants did survive Irma’s initial assault on the Atlantic side, they now exhibited severe salt damage. Beyond the Atlantic side, tree conditions improved and were less severe in the areas behind the steep hillsides of the ocean shore.
The Dutch side had a large number of plants and trees that survived the winds of Irma. However, many of the failures and losses of trees were due to previous defects like co-dominant branch unions, poor root configurations and trees with canopies that had irregular architecture. Notably, many of the non-native palms like coconut palms (Cocos nucifera) with extended fronds were ripped apart while native cabbage palms with more uniform or stout leaf petioles survived and exhibited minimal post-storm injuries.
Additionally, the survivor trees contained a number of injuries caused by wind-driven forces of bending, salt injury, tattered and torn leaves and trunk wounds from flying debris. Many of the trees contained upper branches and smaller stems covered in salt and sand that was stuck between the ridges or furrows of the bark. Many of the trees that did survive contained symptoms of salt injury and secondary pests such as caterpillar and scale damage. The non-native Palm trees like date palms (Phoenix dactylifera) exhibited possible symptoms of lethal yellows caused by a Phytoplasma.
San Juan – Prior to Hurricane Irma and Maria
Puerto Rico is an island that is situated 980 miles from the US mainland and is located just to the east of the Dominican Republic and west of St. Martin. Puerto Rico has over 500 species of trees and plants native to this island mass of 3,515 square miles, and 200 other species of plants introduced from other parts of the world (Little. Wadsworth.1964). Most of my previous tree and plant experiences have been in and near the capitol of San Juan. San Juan is a large city that is made of two districts known as “Old” and “New.” The focus of my research was in Old San Juan. This section of the city was built sometime around 1521 and is made of buildings and structures that have withstood previous hurricane events. More so, Old San Juan is made up of a number of pocket parks and this is where I focused on a comparative analysis of what happens to trees and plants under hurricane conditions. These areas are dominated with the official tree of Puerto Rico, which is the Ceiba, also called silk-cotton tree or kapok tree. Often the tallest tree in the forest, the Ceiba attains heights of 150 feet and has a ridged columnar trunk and a massive umbrella-shaped canopy.
San Juan – Post Hurricane Irma and Maria
After Irma hit San Juan, the island was struck by Maria with winds of approximately 155 mph, the initial photographs and reports provided information that the loss of trees was catastrophic and my expectations of finding many survivor trees were doubtful. However, I was pleasantly surprised to find many of the same trees that I had enjoyed in the past had survived and exhibited little structural damage. The trees that were located in pocket parks and located right near the seashores in many cases were still alive and were re-leafing out. The underlying theme of damage that I observed was that trees that had experienced previous hurricane events and had been appropriately pruned and managed historically exhibited limited losses and injuries from these storms. In addition, trees with a balanced architecture were less likely to fail than those that were irregularly shaped.
Tree Survivor Notes
As part of my investigation, I observed the following conditions to the species of trees that survived on both St. Martin and in San Juan.
Tree Species Observations
royal poincea (Delonix regia) Outer smaller branches damaged
gum tree (Bursera simaruba) Limited outer small stem failures
redwood (Inga laurina) Salt injury and scaffold branches split in the middle
crape myrtle (Lagerstroemia indica) Salt injury
koelreuteria (Koelreuteria paniculata) Co-dominant stems failed
ceiba/kapok tree (Ceiba pentandra) 30% outer crown loss. Completely re-leafed out
geiger tree (Cordia sebestena) No injury because of high salt tolerance
jacaranda (Jacaranda mimosifolia) Many uproot failures and outer branch flagging,limited salt injury
schefflera (Schefflera actinophylla) Failed at the plants base. Now re-growing from the soil line
yellow poinciana (Peltophorum pterocarpum) Secondary branch failures at co-dominant unions
Hong Kong orchid tree (Bauhinia blakeana) Complete defoliation, new leaves with salt injury, smaller branches broken, and scaffold limbs depict no injuries
woman’s tongue tree (Albizia lebbeck) Completely dead in unprotected locations
pink and white shower tree (Cassia species) New leaf emergence with minimal salt injury
papaya (Carica papaya) Remarkable, no damage observed, lost leaves released
sausage tree (Kigelia africana) Larger branch failures on trees with irregular architecture
guavaberry tree (Myrciaria floribunda) Outer canopy dieback with severe trunk and stem damages
columnar cactus (Stenocereus griseus, Blown over, appear to be still alive with dead outer pads
cereus repandus, Pilosocereus lanuginosus)
royal palm (Roystonea regia) Many failures - Surviving trees have the outer sheath surrounding terminal buds severely damaged. The longest fronds were destroyed by ripping off or hanging. Existing foliage is salt/wind burned while new leaves are emerging.
coconut palm (Cocos nucifera) Surviving trees severe salt injury and not likely to recover
saw palmetto (Serenoa repens) Just wind shredded leaves and little salt injury
manila palm or littlerRoyal (Veitchia merrillii) Some damage, mostly longest fronds. Apparently salt tolerant
lady palm (Rhapis excels) Heavy damage by wind and loss of fronds. No salt tolerance
jelly palm (Butia capitata) Few lower fronds damaged. Excellent salt tolerance
queen palm (Arecastrum romanzoffianium) Heavily damaged crowns and trunk damage from storm debris, salt injury and secondary pest activity
cabbage palm (Sabel palmetto) Very little damaged observed
Washingtonia palm (Washingtonia robusta) Many top failures at growing points. Survivors experienced severe loss of leaves and no re-growth.
fishtail palm (Caryota mitis) Severe injury from the event. Many re-sprouts at the base
bottle palm (Hyophorbe lagenicaulis) Loss of lower third of fronds
solitairep palm (Ptychosperma elegans) Heavily damaged crowns and trunk damage from storm debris Salt injury and secondary pest activity
arecap palm (Dypsis lutescens) Heavily damaged crowns, little salt injury, re-growth at base
thatch palm (Leucothrinax morrisii) Very little injury
date palms (Phoenix dactylifera) Heavy damaged crowns and outer trunks damaged from storm debris, salt injury and secondary pest activity
Canary Island date palm (Phoenix canariensis) Heavy damage
sago palms (Cycas sp) Completely destroyed
travelers tree (Ravenala madagascariensis) Heavy losses, but re-sprouting from base
Norfolk Island pine (Araucaria heterophylla) Little injury
red mangrove (Rhizophora mangle) Complete death - Regrowth occurring from seedlings
white mangrove (Laguncularia racemose) 50% Canopy loss
black mangrove (Avicennia germinans) Widespread fatalities
weeping banyan (Ficus benjamina) Minimal injury
strangler fig (Ficus aurea) Outer secondary branch damage
Australian pines (Casuarina equisetifolia) No injuries
locust tree (Hymenaea courbaril), tamarind Very little damage to any of these
(Tamarindus indica), white cedar (Tabebuia
pallida), e Casha (Acacia spec.), black cherry
(Randia aculeata), thornless West Indian cherry
(Malpighia emarginata), mimosa (Leucaena
leucocephala)
Lessons Learned
What the USDA Forest Service and other scientists have learned is that regrowth in most circumstances is about two to three times as robust and productive as normal tree health. This occurs if the tree was not destroyed. In many cases, scientists state that it took trees approximately three to four years to recover after Hurricane Hugo, and it probably will be the same for Irma and Maria as well.
Proper Tree Care Matters
My observations found common traits among the survivor trees. If the tree was in good health and structural condition prior to these events, it was a likely candidate to survive as long as it was a species that had its origins in areas that experience hurricane events. Remarkably, the trees in the pocket parks of San Juan were virtually unscathed, and they were in excellent condition prior to the storms.
Species Selection Matters
My review found a common factor that tree species that were native to this area and experienced prior hurricane events are likely good choices for future plantings. This observation was confirmed (Duryea, Kampf 2017) that native trees survived better in south Florida hurricanes, but not in north Florida such as from Hurricane Ivan. This same research found that native species also lost fewer branches than exotic species in Jeanne (36% versus 21%) and Charley (39% versus 36%) in south Florida.
Excurrent Verses Decurrent
Trees with an excurrent (central) leader system will likely sustain fewer injuries than those species with decurrent (broad and wide shaped) canopies (Dunster et al. 2013). Decurrent species that contain 60 – 90 degree branch angles are excellent candidates to be survivor trees. The lack of failures seen in the tree species Norfolk Island pine (Araucaria heterophylla) demonstrated that excurrent habits in trees are essential for surviving winds. The same conclusions were drawn with decurrent trees like the gum tree (Bursera simaruba), with its wide trunk and 90 degree branch arrangements.
Tree Architectural Design
Trees with unbalanced canopies or with long leaves like palm species or trees with growth patterns that result in weak structure or imbalances are said to have poor architecture. A tree’s poor architecture can be traced in some cases to the lack of pruning or to plant selection. Trees combining poor architecture with other defects have a very high failure potential.
Adaptive Growth
Trees can selectively add extra wood to reinforce those parts of the trunk which are structurally overloaded. Adaptive growth allows trees to optimize their trunks, branches, and roots in order to reduce the chances of mechanical failure under conditions of extreme loading caused by wind, snow, or ice.
Group Plantings
Trees that exist in group plantings are more likely to provide wind protection to each other than trees planted as individuals (Duryea .Kampf .2017). In Hurricanes Ivan and Jeanne, researchers demonstrated that trees growing in groups survived the winds better than individual trees (80% versus 70% in Hurricane Ivan, and 88% versus 78% in Hurricane Jeanne.) A group was defined as 5 or more trees, each growing within 10 feet of each other but not in a row.
Mark A. Webber is a Board-Certified Master Arborist, License Tree Expert, and a Tree Risk Qualified Assessor.
Sources
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By Mark A. Webber
The hurricane season in 2017 made headlines all over the world. Many of these storms were concentrated in the Atlantic Ocean Basin. The 2017 hurricane season was well above the 30-year average with the number of storms and became one of the 10 most active Atlantic seasons on record.
Hurricane Maria's Category 4 landfall on Puerto Rico was a worst-case event, and resulted with power being lost to more than 90% of the island, along with disrupted cell and water service. At least 51 people were killed by Maria in Puerto Rico and significant tree damage was also reported.
Hurricane Irma killed dozens of people and injured others. This record-breaking storm roared over the Dutch and French island of Sint Maarten (St. Martin) with reported winds topping at 185 miles (295 kilometers) per hour. According to the US National Hurricane Center, Irma was one of the strongest storms ever recorded in the Atlantic Ocean.
Background
Since 1988, I have been learning about tropical trees and plants and have annually visited St. Martin and San Juan, Puerto Rico. In February of 2018, approximately five months after the effects of these two major hurricanes I went back to the islands to witness what happened to the trees that I had been learning about. More so, what lessons could be learned for the future management and care of trees in the urban landscape. As part of my investigation, I compared photographs of the trees and plants from previous visits to the islands to the conditions I witnessed in 2018. In addition, I conducted interviews with people who were on the ground when these two weather events occurred.
St. Martin – Prior to Hurricane Irma
The island of St. Martin is made up of two political divisions and is 13 square miles (Britannica.com) in area. The east side of the island is French and is situated with the Atlantic Ocean on its eastern shore. The west side is Dutch and is situated with the Caribbean Sea on its western shore.
Prior to Hurricane Irma, the Dutch side had approximately 15 native trees species. Most of these trees were configured with the adaptive growth of large thick trunks and the scaffolding limbs that were typically at 60 to 90 degree trunk/branch angles. Those species include the gum tree (Bursera simaruba) ,redwood (Inga laurina), white frangepane (Plumeria alba), loblolly (Pisonia fragrans), devil's tree (Morisonia americana), locust tree (Hymenaea courbaril), tamarind (Tamarindus indica),white cedar (Tabebuia pallida) , e casha (Acacia spec.) black cherry (Randia aculeata), thornless West Indian cherry (Malpighia emarginata), mimosa (Leucaena leucocephala) and ficus species like Ficus urbaniana. Most trees on the island are shrub-like and the ground is often covered with a layer of cacti of the genus Opuntia.
The French side St. Martin in the areas along the seashore contained dense populations of mangrove trees. Mangroves have an important ecological niche to local ecosystems and are made up of three unique tree species (Rojer1997). They are red mangrove (Rhizophora mangle) black mangrove (Avicennia germinans), and white mangrove (Laguncularia racemosa).
Throughout the urbanized areas of both the Dutch and French sides, other plantings were made up of a mix of native and non-native species like palms, cactus, fruit bearing trees and tropical plants from other regions of the world.
St. Martin – Post Hurricane Irma
Weather reports stated that St. Martin sustained winds in excess of 185 miles per hour and photographs after the storm depict trees and debris was everywhere, and a number of buildings had collapsed. Additionally, eyewitness accounts described flooded conditions.
My investigation found the surrounding steep hillsides of the French side of St. Martin where Irma first breached were still brown when I observed them in February of 2018. These areas are where the hurricane winds had the most impact. These areas consisted of steep hillsides that were protected by topography contained vegetation that had been defoliated by the strong winds and were now re-growing. Additionally, very few trees situated on the Atlantic side of island survived unless they were sheltered by other trees, buildings or structures. In fact, whole groves of trees in some cases were destroyed without any survivors. More compelling is the complete death of the mangroves along the shoreline and coconut palms that were pulled out the soil by the forces of Irma. Along approximately 15 miles of coastline, I only observed 20 – 25 trees that remained. This same section of coastline a year ago contained thousands of trees. The trees that survived Irma's wrath in most cases were cabbage palms (Sabal palmetto). If trees or small plants did survive Irma’s initial assault on the Atlantic side, they now exhibited severe salt damage. Beyond the Atlantic side, tree conditions improved and were less severe in the areas behind the steep hillsides of the ocean shore.
The Dutch side had a large number of plants and trees that survived the winds of Irma. However, many of the failures and losses of trees were due to previous defects like co-dominant branch unions, poor root configurations and trees with canopies that had irregular architecture. Notably, many of the non-native palms like coconut palms (Cocos nucifera) with extended fronds were ripped apart while native cabbage palms with more uniform or stout leaf petioles survived and exhibited minimal post-storm injuries.
Additionally, the survivor trees contained a number of injuries caused by wind-driven forces of bending, salt injury, tattered and torn leaves and trunk wounds from flying debris. Many of the trees contained upper branches and smaller stems covered in salt and sand that was stuck between the ridges or furrows of the bark. Many of the trees that did survive contained symptoms of salt injury and secondary pests such as caterpillar and scale damage. The non-native Palm trees like date palms (Phoenix dactylifera) exhibited possible symptoms of lethal yellows caused by a Phytoplasma.
San Juan – Prior to Hurricane Irma and Maria
Puerto Rico is an island that is situated 980 miles from the US mainland and is located just to the east of the Dominican Republic and west of St. Martin. Puerto Rico has over 500 species of trees and plants native to this island mass of 3,515 square miles, and 200 other species of plants introduced from other parts of the world (Little. Wadsworth.1964). Most of my previous tree and plant experiences have been in and near the capitol of San Juan. San Juan is a large city that is made of two districts known as “Old” and “New.” The focus of my research was in Old San Juan. This section of the city was built sometime around 1521 and is made of buildings and structures that have withstood previous hurricane events. More so, Old San Juan is made up of a number of pocket parks and this is where I focused on a comparative analysis of what happens to trees and plants under hurricane conditions. These areas are dominated with the official tree of Puerto Rico, which is the Ceiba, also called silk-cotton tree or kapok tree. Often the tallest tree in the forest, the Ceiba attains heights of 150 feet and has a ridged columnar trunk and a massive umbrella-shaped canopy.
San Juan – Post Hurricane Irma and Maria
After Irma hit San Juan, the island was struck by Maria with winds of approximately 155 mph, the initial photographs and reports provided information that the loss of trees was catastrophic and my expectations of finding many survivor trees were doubtful. However, I was pleasantly surprised to find many of the same trees that I had enjoyed in the past had survived and exhibited little structural damage. The trees that were located in pocket parks and located right near the seashores in many cases were still alive and were re-leafing out. The underlying theme of damage that I observed was that trees that had experienced previous hurricane events and had been appropriately pruned and managed historically exhibited limited losses and injuries from these storms. In addition, trees with a balanced architecture were less likely to fail than those that were irregularly shaped.
Tree Survivor Notes
As part of my investigation, I observed the following conditions to the species of trees that survived on both St. Martin and in San Juan.
Tree Species Observations
royal poincea (Delonix regia) Outer smaller branches damaged
gum tree (Bursera simaruba) Limited outer small stem failures
redwood (Inga laurina) Salt injury and scaffold branches split in the middle
crape myrtle (Lagerstroemia indica) Salt injury
koelreuteria (Koelreuteria paniculata) Co-dominant stems failed
ceiba/kapok tree (Ceiba pentandra) 30% outer crown loss. Completely re-leafed out
geiger tree (Cordia sebestena) No injury because of high salt tolerance
jacaranda (Jacaranda mimosifolia) Many uproot failures and outer branch flagging,limited salt injury
schefflera (Schefflera actinophylla) Failed at the plants base. Now re-growing from the soil line
yellow poinciana (Peltophorum pterocarpum) Secondary branch failures at co-dominant unions
Hong Kong orchid tree (Bauhinia blakeana) Complete defoliation, new leaves with salt injury, smaller branches broken, and scaffold limbs depict no injuries
woman’s tongue tree (Albizia lebbeck) Completely dead in unprotected locations
pink and white shower tree (Cassia species) New leaf emergence with minimal salt injury
papaya (Carica papaya) Remarkable, no damage observed, lost leaves released
sausage tree (Kigelia africana) Larger branch failures on trees with irregular architecture
guavaberry tree (Myrciaria floribunda) Outer canopy dieback with severe trunk and stem damages
columnar cactus (Stenocereus griseus, Blown over, appear to be still alive with dead outer pads
cereus repandus, Pilosocereus lanuginosus)
royal palm (Roystonea regia) Many failures - Surviving trees have the outer sheath surrounding terminal buds severely damaged. The longest fronds were destroyed by ripping off or hanging. Existing foliage is salt/wind burned while new leaves are emerging.
coconut palm (Cocos nucifera) Surviving trees severe salt injury and not likely to recover
saw palmetto (Serenoa repens) Just wind shredded leaves and little salt injury
manila palm or littlerRoyal (Veitchia merrillii) Some damage, mostly longest fronds. Apparently salt tolerant
lady palm (Rhapis excels) Heavy damage by wind and loss of fronds. No salt tolerance
jelly palm (Butia capitata) Few lower fronds damaged. Excellent salt tolerance
queen palm (Arecastrum romanzoffianium) Heavily damaged crowns and trunk damage from storm debris, salt injury and secondary pest activity
cabbage palm (Sabel palmetto) Very little damaged observed
Washingtonia palm (Washingtonia robusta) Many top failures at growing points. Survivors experienced severe loss of leaves and no re-growth.
fishtail palm (Caryota mitis) Severe injury from the event. Many re-sprouts at the base
bottle palm (Hyophorbe lagenicaulis) Loss of lower third of fronds
solitairep palm (Ptychosperma elegans) Heavily damaged crowns and trunk damage from storm debris Salt injury and secondary pest activity
arecap palm (Dypsis lutescens) Heavily damaged crowns, little salt injury, re-growth at base
thatch palm (Leucothrinax morrisii) Very little injury
date palms (Phoenix dactylifera) Heavy damaged crowns and outer trunks damaged from storm debris, salt injury and secondary pest activity
Canary Island date palm (Phoenix canariensis) Heavy damage
sago palms (Cycas sp) Completely destroyed
travelers tree (Ravenala madagascariensis) Heavy losses, but re-sprouting from base
Norfolk Island pine (Araucaria heterophylla) Little injury
red mangrove (Rhizophora mangle) Complete death - Regrowth occurring from seedlings
white mangrove (Laguncularia racemose) 50% Canopy loss
black mangrove (Avicennia germinans) Widespread fatalities
weeping banyan (Ficus benjamina) Minimal injury
strangler fig (Ficus aurea) Outer secondary branch damage
Australian pines (Casuarina equisetifolia) No injuries
locust tree (Hymenaea courbaril), tamarind Very little damage to any of these
(Tamarindus indica), white cedar (Tabebuia
pallida), e Casha (Acacia spec.), black cherry
(Randia aculeata), thornless West Indian cherry
(Malpighia emarginata), mimosa (Leucaena
leucocephala)
Lessons Learned
What the USDA Forest Service and other scientists have learned is that regrowth in most circumstances is about two to three times as robust and productive as normal tree health. This occurs if the tree was not destroyed. In many cases, scientists state that it took trees approximately three to four years to recover after Hurricane Hugo, and it probably will be the same for Irma and Maria as well.
Proper Tree Care Matters
My observations found common traits among the survivor trees. If the tree was in good health and structural condition prior to these events, it was a likely candidate to survive as long as it was a species that had its origins in areas that experience hurricane events. Remarkably, the trees in the pocket parks of San Juan were virtually unscathed, and they were in excellent condition prior to the storms.
Species Selection Matters
My review found a common factor that tree species that were native to this area and experienced prior hurricane events are likely good choices for future plantings. This observation was confirmed (Duryea, Kampf 2017) that native trees survived better in south Florida hurricanes, but not in north Florida such as from Hurricane Ivan. This same research found that native species also lost fewer branches than exotic species in Jeanne (36% versus 21%) and Charley (39% versus 36%) in south Florida.
Excurrent Verses Decurrent
Trees with an excurrent (central) leader system will likely sustain fewer injuries than those species with decurrent (broad and wide shaped) canopies (Dunster et al. 2013). Decurrent species that contain 60 – 90 degree branch angles are excellent candidates to be survivor trees. The lack of failures seen in the tree species Norfolk Island pine (Araucaria heterophylla) demonstrated that excurrent habits in trees are essential for surviving winds. The same conclusions were drawn with decurrent trees like the gum tree (Bursera simaruba), with its wide trunk and 90 degree branch arrangements.
Tree Architectural Design
Trees with unbalanced canopies or with long leaves like palm species or trees with growth patterns that result in weak structure or imbalances are said to have poor architecture. A tree’s poor architecture can be traced in some cases to the lack of pruning or to plant selection. Trees combining poor architecture with other defects have a very high failure potential.
Adaptive Growth
Trees can selectively add extra wood to reinforce those parts of the trunk which are structurally overloaded. Adaptive growth allows trees to optimize their trunks, branches, and roots in order to reduce the chances of mechanical failure under conditions of extreme loading caused by wind, snow, or ice.
Group Plantings
Trees that exist in group plantings are more likely to provide wind protection to each other than trees planted as individuals (Duryea .Kampf .2017). In Hurricanes Ivan and Jeanne, researchers demonstrated that trees growing in groups survived the winds better than individual trees (80% versus 70% in Hurricane Ivan, and 88% versus 78% in Hurricane Jeanne.) A group was defined as 5 or more trees, each growing within 10 feet of each other but not in a row.
Mark A. Webber is a Board-Certified Master Arborist, License Tree Expert, and a Tree Risk Qualified Assessor.
Sources
- Broschat, Timothy K. and Jonathan H. Crane, “The Coconut Palm in Florida”, . University of Florida.2015
- Dunster, J. and E.T. Smiley, N. Matheny, and S. Lilly, “Tree Risk Assessment - Manual”, International. Society of Arboriculture, Champaign, IL, 2013.
- Duryea, Mary L. and Eliana Kampf. “Wind and Trees: Lessons Learned from Hurricanes”, The University of Florida. 2017
- Forman, RTT, “An introduction to the ecosystems and plants on St. Croix, US Virgin Islands”, West Indies Laboratory,1974.
- Howard, F.W. (1992) “Susceptibility of date palms to lethal yellowing in Florida”, Principles 36, 217–222.
- Rojer, Anna, “Biological Inventory of St. Maarten”, 1997.
- Schubert, Thomas H. “Trees for Urban Use in Puerto Rico and the Virgin Islands”, Gen.Tech. Rep. SO-27. New Orleans, LA: U.S.D.A., Forest Service, Southern Forest Experiment Station 1979.
- The Weather Channel, “2017 Atlantic Hurricane Season Recap: 17 Moments We'll Never Forget” February 23, 2018.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, Aerial Lift Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Outstanding Forestry Departments
Edited by Len Phillips with support from LinkedIn's Urban Forestry Discussion Group
What does it take to have an outstanding city forestry department? Lots of hard work, an able staff, and strong support from city leaders and city residents.
Staff
The forestry department must have a well-trained and responsive certified arborist leading a staff of support personnel, including ISA certified tree workers or arborists who are able to handle multiple tree concerns. This includes tree installations, trimming, and removals, as well as dealing with pests and diseases in the trees. Most importantly is understanding the concerns of the city's residents. The tree department must also have the appropriate resources and budget to manage the city's trees in a proactive manner. All the employees should also know the local laws and policies and how to work within them to develop an outstanding city forest. The arborist in charge and the employees should be hired based on qualifications and not political connections.
Tree Advisory Board
The arborist in charge of an outstanding forestry department should receive directions from a group of residents that are interested in the care of trees in their city. This group of politically connected citizens should be appointed by the city mayor or council to form a Tree Advisory Board. This Board will establish guidelines for how the city's investment in the city's trees are protected. The Board should also keep the public informed with knowledge about the city's tree management program, listen to their questions, and answer them with the most up-to-date information available. The Board should encourage the city to be prepared to pay for a pruning cycle of less than 10 years. The Board should also work with the department to develop a plan to diversify the city's tree population with native species as well as nativars (cultivars of native species), and trees selected for urban environment tolerance and future climate change.
Equipment
The forestry department should have up-to-date equipment that is well maintained, cared for, and certified for safety. The vehicles must be fully operational and a fresh coat of paint applied once in a while. This is good for creating a positive image and pride from the employees. The employees should also have all their personal safety equipment and maintenance tools up-to-date and in good condition.
Management Plan
The most important document is a well thought out city forest management plan that was developed by an inter-disciplinary group of community leaders including the Tree Advisory Board and the city arborist. Resident participation in the vision and a feedback process adds confidence in the ability of the department to identify, implement, and manage the resource with competence.
The management plan must include an enforceable ordinance that protects the forest resource from the public as well as from private exploitation. The ordinance should include a policy that requires one tree installed for every public tree removed. There should be polices added to the ordinance so that the current professional ANSI Standards are referenced and followed by the tree department. The management plan might also encourage free training programs about tree installations, structural pruning from the ground, and learning about how trees grow, for concerned, interested community members, and potential volunteers to assist the department.
Inventory
Appended to the plan should be a complete ground-based inventory and all public trees, including GPS locations, which could be referenced on other public infrastructure projects. The data collected should be incorporated into the public tree inventory data including tree planting, maintenance, remedial actions, and abuse records. If the data is maintained through computer software, it is easy to add and subtract data from the field. In addition, it is extremely useful when dealing with public complaints and inquiries.
Department Functions
The department must try to satisfy public needs as much as possible and show constant work for improvement. Any and all contracted work should not be "low bid" work without the bidder being able to prove verifiable experience in delivering a product that includes up-to-date professional care of trees. The department must also oversee all tree related specifications for any and all public infrastructure projects.
The tree department must encourage coordination with other essential service departments like streets, water, communications, and electric utilities to prevent and control tree installations in their corridors and find engineering solutions like using root barriers to make sure that trees roots will not affect or penetrate the underground services.
Since the city forest belongs to everyone, it can not be managed well if the public is not involved both from a management as well as an advocacy perspective. There are many tasks which often fall by the wayside that the trained public can perform, such as tree maintenance from ground level, mulching, watering, and installing new trees. In addition, an informed public will advocate for adequate funding, for future tree preservation.
Finally, if the city has planned well, then the city will maintain this resource with less effort and cost, and that is a goal of sustainability. With it should come the recognition of having an outstanding urban forestry program.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips with support from LinkedIn's Urban Forestry Discussion Group
What does it take to have an outstanding city forestry department? Lots of hard work, an able staff, and strong support from city leaders and city residents.
Staff
The forestry department must have a well-trained and responsive certified arborist leading a staff of support personnel, including ISA certified tree workers or arborists who are able to handle multiple tree concerns. This includes tree installations, trimming, and removals, as well as dealing with pests and diseases in the trees. Most importantly is understanding the concerns of the city's residents. The tree department must also have the appropriate resources and budget to manage the city's trees in a proactive manner. All the employees should also know the local laws and policies and how to work within them to develop an outstanding city forest. The arborist in charge and the employees should be hired based on qualifications and not political connections.
Tree Advisory Board
The arborist in charge of an outstanding forestry department should receive directions from a group of residents that are interested in the care of trees in their city. This group of politically connected citizens should be appointed by the city mayor or council to form a Tree Advisory Board. This Board will establish guidelines for how the city's investment in the city's trees are protected. The Board should also keep the public informed with knowledge about the city's tree management program, listen to their questions, and answer them with the most up-to-date information available. The Board should encourage the city to be prepared to pay for a pruning cycle of less than 10 years. The Board should also work with the department to develop a plan to diversify the city's tree population with native species as well as nativars (cultivars of native species), and trees selected for urban environment tolerance and future climate change.
Equipment
The forestry department should have up-to-date equipment that is well maintained, cared for, and certified for safety. The vehicles must be fully operational and a fresh coat of paint applied once in a while. This is good for creating a positive image and pride from the employees. The employees should also have all their personal safety equipment and maintenance tools up-to-date and in good condition.
Management Plan
The most important document is a well thought out city forest management plan that was developed by an inter-disciplinary group of community leaders including the Tree Advisory Board and the city arborist. Resident participation in the vision and a feedback process adds confidence in the ability of the department to identify, implement, and manage the resource with competence.
The management plan must include an enforceable ordinance that protects the forest resource from the public as well as from private exploitation. The ordinance should include a policy that requires one tree installed for every public tree removed. There should be polices added to the ordinance so that the current professional ANSI Standards are referenced and followed by the tree department. The management plan might also encourage free training programs about tree installations, structural pruning from the ground, and learning about how trees grow, for concerned, interested community members, and potential volunteers to assist the department.
Inventory
Appended to the plan should be a complete ground-based inventory and all public trees, including GPS locations, which could be referenced on other public infrastructure projects. The data collected should be incorporated into the public tree inventory data including tree planting, maintenance, remedial actions, and abuse records. If the data is maintained through computer software, it is easy to add and subtract data from the field. In addition, it is extremely useful when dealing with public complaints and inquiries.
Department Functions
The department must try to satisfy public needs as much as possible and show constant work for improvement. Any and all contracted work should not be "low bid" work without the bidder being able to prove verifiable experience in delivering a product that includes up-to-date professional care of trees. The department must also oversee all tree related specifications for any and all public infrastructure projects.
The tree department must encourage coordination with other essential service departments like streets, water, communications, and electric utilities to prevent and control tree installations in their corridors and find engineering solutions like using root barriers to make sure that trees roots will not affect or penetrate the underground services.
Since the city forest belongs to everyone, it can not be managed well if the public is not involved both from a management as well as an advocacy perspective. There are many tasks which often fall by the wayside that the trained public can perform, such as tree maintenance from ground level, mulching, watering, and installing new trees. In addition, an informed public will advocate for adequate funding, for future tree preservation.
Finally, if the city has planned well, then the city will maintain this resource with less effort and cost, and that is a goal of sustainability. With it should come the recognition of having an outstanding urban forestry program.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Tree of the Seminar #79
By Len Phillips
Ivory Spear™ Crabapple is a tree with deep pink buds that open to white flowers on this densely upright, narrow crabapple. Leaves stay clean and disease free throughout the growing season. Bright cherry red fruits contrast well with the dark green leaves and persist into late autumn, when a touch of yellow autumn color adds seasonal interest.
Trade Name: Ivory Spear™ Crabapple
Botanical Name: Malus 'JFS KW214MX' P.A.F.
Family: Rosaceae
Parentage: Selection made in Illinois in 1982, now being released as a new cultivar
Height: 18'- 20'
Spread: 6'- 8'
Form: Narrow, upright, tightly columnar
Bloom Period: With bud break, late April – early May in most climates
Flower: Deep pink buds that open to white flowers, long lasting bloom
Fruit: Bright red, ½" diameter, summer to late autumn
Foliage: Dark green in summer, yellow in autumn, clean disease free leaves
Bark: Reddish brown bark is attractive in winter
Habitat: Does very well throughout the U.S.
Hardiness Zone: 4 – 8, AHS Heat Zone 8 – 1
Site Requirements: Well drained soil, full sun, acidic soil
Growth Rate: Vigorous, densely branched, full size in 30 years
Pest Problems: Very tolerant of diseases with excellent resistance to scab, mildew, fireblight, and Cedar-Apple Rust
Storm Resistance: Average for the species
Salt Tolerance: Average for the species
Installation: Transplants easily, select trees grown on own roots to minimize sucker growth. Fibrous roots allow any transplanting technique, including bare root, in spring only, suitable for CU-Structural Soil planting
Pruning: Prune broken and dead branches at planting and 3 years later to mature form
Propagating: Budding, grafting, softwood cuttings
Design Uses: Excellent in parks, residential areas, golf courses, and commercial areas
Companions: Use with groundcovers such as Sedum, Ajuga, Galium, and Chrysoganum
Other Comments: Forms a uniform column of dark green foliage in the landscape.
Photo
Sources:
This information has been gathered from personal observations of the author, living in Massachusetts, Zone 6 and information provided by our sponsor J. Frank Schmidt & Son.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Len Phillips
Ivory Spear™ Crabapple is a tree with deep pink buds that open to white flowers on this densely upright, narrow crabapple. Leaves stay clean and disease free throughout the growing season. Bright cherry red fruits contrast well with the dark green leaves and persist into late autumn, when a touch of yellow autumn color adds seasonal interest.
Trade Name: Ivory Spear™ Crabapple
Botanical Name: Malus 'JFS KW214MX' P.A.F.
Family: Rosaceae
Parentage: Selection made in Illinois in 1982, now being released as a new cultivar
Height: 18'- 20'
Spread: 6'- 8'
Form: Narrow, upright, tightly columnar
Bloom Period: With bud break, late April – early May in most climates
Flower: Deep pink buds that open to white flowers, long lasting bloom
Fruit: Bright red, ½" diameter, summer to late autumn
Foliage: Dark green in summer, yellow in autumn, clean disease free leaves
Bark: Reddish brown bark is attractive in winter
Habitat: Does very well throughout the U.S.
Hardiness Zone: 4 – 8, AHS Heat Zone 8 – 1
Site Requirements: Well drained soil, full sun, acidic soil
Growth Rate: Vigorous, densely branched, full size in 30 years
Pest Problems: Very tolerant of diseases with excellent resistance to scab, mildew, fireblight, and Cedar-Apple Rust
Storm Resistance: Average for the species
Salt Tolerance: Average for the species
Installation: Transplants easily, select trees grown on own roots to minimize sucker growth. Fibrous roots allow any transplanting technique, including bare root, in spring only, suitable for CU-Structural Soil planting
Pruning: Prune broken and dead branches at planting and 3 years later to mature form
Propagating: Budding, grafting, softwood cuttings
Design Uses: Excellent in parks, residential areas, golf courses, and commercial areas
Companions: Use with groundcovers such as Sedum, Ajuga, Galium, and Chrysoganum
Other Comments: Forms a uniform column of dark green foliage in the landscape.
Photo
Sources:
This information has been gathered from personal observations of the author, living in Massachusetts, Zone 6 and information provided by our sponsor J. Frank Schmidt & Son.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Moving Trees with Air
Edited by Len Phillips
Bare root (BR) transplanting with high pressure air is actually an old method using modern tools and technology developed in the late 1990's. The Air-Spade® was introduced to the tree industry and promoted mainly to diagnose and treat root problems. The Air-Spade® is a venturi nozzled apparatus that attaches to an air compressor modified to generate a supersonic velocity column of air to dislodge soil. When used around trees, it can:
When the Air-Spade® is being used for transplanting trees BR, the soil is blown from above and below the roots. This process allows the tree to retain up to 95% of the root mass, which results in little or no transplant shock. This technique provides the ability to transplant trees throughout the growing season (spring, summer, and autumn) with success. After air spading, the bare roots are sprayed with water and covered with wet burlap for transporting. Regardless of the weather, season, and species, most trees do not even show signs of wilt during the air spading and moving process.
Labor costs for using the Air-Spade® is more than using a tree spade, but equipment costs are much less. Therefore, the total cost for using an Air-Spade® is half the cost of the tree spade. Plus, the tree survival rate is much higher with the Air-Spade® than with the tree spade.
Steps For Moving Trees With An Air-Spade®
Advantages:
People who have used this technique are confident that bare root transplanting is perhaps the best way to relocate a tree and the Air-Spade® will revolutionize transplanting in our industry.
Sources
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
Bare root (BR) transplanting with high pressure air is actually an old method using modern tools and technology developed in the late 1990's. The Air-Spade® was introduced to the tree industry and promoted mainly to diagnose and treat root problems. The Air-Spade® is a venturi nozzled apparatus that attaches to an air compressor modified to generate a supersonic velocity column of air to dislodge soil. When used around trees, it can:
- reduce soil compaction,
- till the soil,
- reveal girdling roots,
- locate the flare,
- locate roots for underground utility installation,
- investigate root damage,
- check the adequacy of the root structure,
- accurately diagnosis root diseases.
When the Air-Spade® is being used for transplanting trees BR, the soil is blown from above and below the roots. This process allows the tree to retain up to 95% of the root mass, which results in little or no transplant shock. This technique provides the ability to transplant trees throughout the growing season (spring, summer, and autumn) with success. After air spading, the bare roots are sprayed with water and covered with wet burlap for transporting. Regardless of the weather, season, and species, most trees do not even show signs of wilt during the air spading and moving process.
Labor costs for using the Air-Spade® is more than using a tree spade, but equipment costs are much less. Therefore, the total cost for using an Air-Spade® is half the cost of the tree spade. Plus, the tree survival rate is much higher with the Air-Spade® than with the tree spade.
Steps For Moving Trees With An Air-Spade®
- Hydrate the tree's roots thoroughly before excavating it. Water deeply at least 72 hours before the move. Clay soil blows out best when it is damp. Sandy soil blows out best when it has drained a bit.
- Tie up any branches that may be in the way during the excavation, moving, and backfilling process.
- Start the excavation process by making a circular trench at the drip line using a small backhoe. With that completed, continue using the backhoe to carefully excavate inward toward the trunk until roots are discovered. Then begin using the Air-Spade® by blowing soil outward and into the circular trench.
- Keep the exposed roots as moist as possible during digging and lifting the roots. As a section is completed, the roots are gathered and tied up in a pigtail fashion, then the pigtail is raised and tied to the tree trunk or lower branches as the roots are moistened again. The Air-Spade® does cause some root drying so moistening the exposed roots is very important.
- Continue this process moving around the tree.
- Once all of the roots are exposed and tied up to the tree, the tree is ready to be moved to the new location, which has been dug the same size as the hole from which the tree is being removed.
- Use a fork lift to lift and transport the tree to its new location.
- Install the tree at the same grade as it was in its original location, taking care to ensure the flair is at the finished grade. The new planting hole will not have to be very deep.
- Untie the roots from the pigtails and spread them out in approximately their same orientation from which they came. Moisten the roots again.
- Options at this point include adding some soil amendments like compost or a fertilizer to promote root growth.
- Backfill with the soil excavated from the new location. The best way to backfill is with labor and shovels. However if equipment is used, be sure it is equipped with wide tracks or tires. Soil compaction is not acceptable after all this effort to protect and save the tree.
- Untie any low branches that may have been tied up to provide clearance under the tree.
- Build a berm of soil at the edge of the new installation excavation.
- Immediately after backfilling, flood the saucer area with water to eliminate air pockets.
- Continue to irrigate the tree throughout the growing season to ensure the tree becomes established.
- Staking is not necessary. If the tree is on a windy site consider adding root staples or other means for anchoring the roots to the bottom of the installation hole.
Advantages:
- As little as 5% – 15% of roots are cut, unlike the conventional methods which cut between 50% – 85% of the root mass. Most of the trees roots are moved with the tree, compared to 30% with a tree spade or 5% by B&B. This means a minimized transplant shock. The tree is also significantly lighter in weight for transporting.
- The Air-Spade® is considered a less expensive option to transplanting than with a tree spade.
- In addition, smaller machines are needed to lift and move the tree.
- The Air-Spade® is useful for transplanting specimen trees.
- Guying is not required.
People who have used this technique are confident that bare root transplanting is perhaps the best way to relocate a tree and the Air-Spade® will revolutionize transplanting in our industry.
Sources
- Foti, Matt,”Bare Root Planting with an Air-Spade®”, New England Grows lecture. 2011.
- Howe, Deborah, “Another air-tool bare-root transplanting”, Taking Place, July 29, 2009.
- Howe, Deborah, “Roots First”, American Nurseryman, December 2008.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
The Care of Trees in Tulsa
Edited by Len Phillips
Tulsa, Oklahoma is a city of over 400,000 people. It is known for its art deco architecture, mostly in the central Deco District. Landmarks like the Philcade and Philtower buildings reflect a 20th-century construction boom, fueled by the prosperous local oil industry.
Even though Tulsa's Park and Recreation Department was established in 1906 and several parks host historic trees that have been preserved since pre-settlement days, urban forestry in Tulsa was not formally recognized until 1992. Since that time, park tree maintenance has steadily increased. Street trees were pruned and maintained by the City on a regular cycle during the 1990s. However, in 2001, the responsibility for their care reverted to the adjacent homeowner.
In 1975, Tulsa's 51st Street was widened and the removal of a vast number of trees was required. A young high school student who lived near the construction zone, wondered how and if the city would replace the trees. He took the initiative to make a phone call to Sid Patterson, the Tulsa Streets Commissioner at that time and asked what the city was doing to replace the trees. Commissioner Patterson was not able to answer that question right away and he learned, in fact, the city was doing little. In Tulsa’s weak economy, times were hard and there were no funds available for trees, let alone the labor to plant and maintain them.
A persuasive man of action however, Commissioner Patterson then began organizing members of the Tulsa Garden Club, local landscape architects, representatives from Rotary Club of Tulsa, and several other civic groups into a group to study Tulsa's trees. During the next year, Patterson caused the seed of an idea to grow into a determined group of volunteers. By 1976, this consistent effort led to the formulation of 'Up With Trees'.
Up With Trees
Up With Trees became Tulsa’s nonprofit urban forest advocate and has been faithful toward its mission to beautify greater Tulsa by installing trees and creating urban forestry awareness through education. Up With Trees partnered with the local groups and companies to give Tulsa a landscape that will benefit future generations. It was planned that 'Up With Trees' operating expenses would be funded through private donations and an annual fundraiser now called the 'Green Leaf Gala'.
During the last four decades, Up With Trees has installed over 30,000 trees at more than 700 sites throughout Tulsa including along streets and trails, in parks, at schools and fire stations, as well as neighborhoods and many other public properties. Up With Trees not only installs, but maintains trees throughout greater Tulsa and works to ensure that these trees are pruned, watered, and replaced if severely damaged. The operations crew is a team of 8 who are trained in safety, equipment operations, proper installation techniques, and proper pruning and maintenance techniques. The crew works with the usual numbers of small tools and equipment as well as using eight trucks.
Up With Trees waters and maintains trees their first 3 years to get them established and then volunteers rotate throughout the city every year to prune the trees that require it. Some of the trees are on properties with dedicated maintenance teams, for example some schools. But for the most part if Up With Trees installed the tree, they perform the structural pruning, watering, and other general maintenance as necessary.
In 2015, recognizing a need to plan for additional tree installation and maintenance in the coming years, Up With Trees collaborated with the City of Tulsa and other urban forest management agencies to begin the process of developing an Urban Forest Master Plan.
Education is one of the most important parts of the Up With Trees organization and it strives to educate as many residents as possible about the importance of keeping Tulsa green. Up With Trees does this through volunteers and a strong Citizen Foresters program. Today the City of Tulsa's urban forest includes over 5.2 million public and private trees. These trees provide beauty and shade, as well as providing benefits to air quality, water quality, energy savings, wildlife, socio-economics, and public health.
The Up With Trees staff recognize that trees have specific needs at various life stages, so they train volunteers in proper structure when they are young trees and then as the trees mature, the volunteers increase monitoring and proactive risk management. The Up With Trees Program Director trains volunteers in a Citizen Forester program that educates members in proper tree maintenance. The Director also trains the public on many other tree-related topics. A good portion of those that go through the classes stay on as volunteers.
The Up With Trees staff also recognize that deferring maintenance can have a significant impact on the overall health, structure, value, and lifespan of a tree. In addition, deferred maintenance often results in higher costs and less beneficial results, including increased risk potential. As a result, Up With Trees identifies goals for optimizing urban forest programming and existing funding, along with personnel training.
The success of Up With Trees clearly illustrates that a private organization, with public support, can be the agency responsible for dedicated municipal tree maintenance.
Sources and more information:
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Tree Worker Specialist, Aerial Lift Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
Tulsa, Oklahoma is a city of over 400,000 people. It is known for its art deco architecture, mostly in the central Deco District. Landmarks like the Philcade and Philtower buildings reflect a 20th-century construction boom, fueled by the prosperous local oil industry.
Even though Tulsa's Park and Recreation Department was established in 1906 and several parks host historic trees that have been preserved since pre-settlement days, urban forestry in Tulsa was not formally recognized until 1992. Since that time, park tree maintenance has steadily increased. Street trees were pruned and maintained by the City on a regular cycle during the 1990s. However, in 2001, the responsibility for their care reverted to the adjacent homeowner.
In 1975, Tulsa's 51st Street was widened and the removal of a vast number of trees was required. A young high school student who lived near the construction zone, wondered how and if the city would replace the trees. He took the initiative to make a phone call to Sid Patterson, the Tulsa Streets Commissioner at that time and asked what the city was doing to replace the trees. Commissioner Patterson was not able to answer that question right away and he learned, in fact, the city was doing little. In Tulsa’s weak economy, times were hard and there were no funds available for trees, let alone the labor to plant and maintain them.
A persuasive man of action however, Commissioner Patterson then began organizing members of the Tulsa Garden Club, local landscape architects, representatives from Rotary Club of Tulsa, and several other civic groups into a group to study Tulsa's trees. During the next year, Patterson caused the seed of an idea to grow into a determined group of volunteers. By 1976, this consistent effort led to the formulation of 'Up With Trees'.
Up With Trees
Up With Trees became Tulsa’s nonprofit urban forest advocate and has been faithful toward its mission to beautify greater Tulsa by installing trees and creating urban forestry awareness through education. Up With Trees partnered with the local groups and companies to give Tulsa a landscape that will benefit future generations. It was planned that 'Up With Trees' operating expenses would be funded through private donations and an annual fundraiser now called the 'Green Leaf Gala'.
During the last four decades, Up With Trees has installed over 30,000 trees at more than 700 sites throughout Tulsa including along streets and trails, in parks, at schools and fire stations, as well as neighborhoods and many other public properties. Up With Trees not only installs, but maintains trees throughout greater Tulsa and works to ensure that these trees are pruned, watered, and replaced if severely damaged. The operations crew is a team of 8 who are trained in safety, equipment operations, proper installation techniques, and proper pruning and maintenance techniques. The crew works with the usual numbers of small tools and equipment as well as using eight trucks.
Up With Trees waters and maintains trees their first 3 years to get them established and then volunteers rotate throughout the city every year to prune the trees that require it. Some of the trees are on properties with dedicated maintenance teams, for example some schools. But for the most part if Up With Trees installed the tree, they perform the structural pruning, watering, and other general maintenance as necessary.
In 2015, recognizing a need to plan for additional tree installation and maintenance in the coming years, Up With Trees collaborated with the City of Tulsa and other urban forest management agencies to begin the process of developing an Urban Forest Master Plan.
Education is one of the most important parts of the Up With Trees organization and it strives to educate as many residents as possible about the importance of keeping Tulsa green. Up With Trees does this through volunteers and a strong Citizen Foresters program. Today the City of Tulsa's urban forest includes over 5.2 million public and private trees. These trees provide beauty and shade, as well as providing benefits to air quality, water quality, energy savings, wildlife, socio-economics, and public health.
The Up With Trees staff recognize that trees have specific needs at various life stages, so they train volunteers in proper structure when they are young trees and then as the trees mature, the volunteers increase monitoring and proactive risk management. The Up With Trees Program Director trains volunteers in a Citizen Forester program that educates members in proper tree maintenance. The Director also trains the public on many other tree-related topics. A good portion of those that go through the classes stay on as volunteers.
The Up With Trees staff also recognize that deferring maintenance can have a significant impact on the overall health, structure, value, and lifespan of a tree. In addition, deferred maintenance often results in higher costs and less beneficial results, including increased risk potential. As a result, Up With Trees identifies goals for optimizing urban forest programming and existing funding, along with personnel training.
The success of Up With Trees clearly illustrates that a private organization, with public support, can be the agency responsible for dedicated municipal tree maintenance.
Sources and more information:
- Up With Trees
- Tulsa Urban Forest Master Plan
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Tree Worker Specialist, Aerial Lift Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
The Shot Hole Borer
Edited by Len Phillips
Scientists have no evidence of how the shot hole borer beetle first entered the United States, but suspect it came in on wooden packing materials from Vietnam. The “Polyphagous shot hole borer” (PSHB) (Euwallacea fornicatus) and the “Kuroshio shot hole borer” (KSHB) are now referred to collectively as the “Invasive Shot Hole Borer” (ISHB). This pest was first caught in California in 2003. PSHB is found in a currently limited range on the coast of California, from Los Angeles south to San Diego. It has also been found in Israel. This tiny beetle is the size of a sesame seed and is identified as a type of Ambrosia beetle of which there are 3,500 species, most of which partner with fungi to decompose dead trees. Female beetles make tunnels, or galleries, in the trunks and branches of host trees and lay their eggs inside. Males are much smaller, do not fly, and don’t leave the galleries.
When a female Ambrosia beetle finds a suitable tree, she chews a tunnel into the sapwood and “plants” a fungus as she digs. Ambrosia beetles have special pits or dents in their bodies (called mycangia) that are used to carry the spores of fungi. The fungus then grows into the tree’s wood and on the walls of the beetle galleries providing a fresh crop of fungal food for both PSHB and ISHB beetles. The relationship between the beetle and the fungus is called ‘symbiotic', meaning that these two very different species depend on each other. The fungus provides a ready source of food for the beetle and the beetle provides the fungus with a free ride to new trees.
Part of the reason this beetle is so destructive is that it has a huge appetite for the fungus. In fact, it has been known to attack plants in 58 different families. Many of these plants are important parts of the native California ecosystems, and others are planted widely across the U.S. in cities and neighborhoods. A few host species, like avocado and olive, are also important in agriculture. By 2010, hundreds of boxelders (Acer negundo) lining the streets in Long Beach, CA, were injured or killed by the beetle and had to be removed. The beetle then moved on to California sycamores (Platanus racemosa), killing thousands on streets, in yards, public parks, and wilderness areas.
The KSHB appeared south of Long Beach and it has killed over 180,000 willows in the Tijuana River Valley. The willows include: Weeping willow (Salix babylonica), Goodding's black willow (Salix gooddingii), and Red Willow (Salix laevigata). This area happens to coincide with a critical breeding area and habitat for a rare vireo (Vireonidae) and willow flycatcher (Empidonax traillii extimus). Both birds are listed as endangered species. In addition the loss of the willows shading the river affects all the aquatic organisms, crawdads, and fish because the water has become too hot for them to live in.
The ISHB has a wide plant palette. More than 360 tree species have been attacked and ISHB is able to reproduce in at least 62 species of plants and trees. This beetle does not eat the wood, it just bores into the tree, carrying a number of different fungi that cause Fusarium (Fusarium euwallaceae) dieback and in many cases, death. The borer attacks healthy trees because the fungi it carries needs the water and nutrients from living trees to grow. The beetle is able to reproduce in many tree species, but is repelled by others. For example, pines block them at the holes with resin and cherry species exude a juice that turns hard as amber. However, once the beetle is in the tree, nothing will work.
So far, PSHB has been found infesting trees in neighborhoods, avocado farms, and several public gardens. Because PSHB can attack so many different types of trees, California woodlands are also at risk as the beetle continues to spread.
In their native homes, ambrosia beetles usually only attack sick or dead trees. However, when they are accidentally moved to new habitats, they begin attacking healthy trees.
Affected Species
The beetle's first favorite species was avocado (Persea americana). The avocado trees suffer with wilt and branch dieback. However they seem to survive and still bear fruit. Their next most favorite species is the box elder, followed by sycamore, and currently the beetles are attacking English oak (Quercus robur), California live oak (Quercus agrifolia), and valley oak (Quercus lobata).
Treatments
Trimming diseased branches, then chipping and grinding the wood and covering the material to heat up in the sun, kills about 98% of the beetles. There are no other effective treatments. There are also no known trees that are resistant to the bacteria. However, science is close to finding a treatment process that might prevent the bacteria from causing death to the trees. Researchers are also working on a couple of insect predators, but testing such biological agents takes years.
Before a treatment is found, the undeterred shot hole borer will thrive in hotter cities with higher ozone pollution and carbon dioxide levels. They will also thrive in major storms and trees affected by impaired water quality. This will result in unknown tolls on wildlife and human health.
Before treatments and pest resistance provide a suitable treatment, scientists predict this pest will cause an epidemic as significant as Dutch elm disease and chestnut blight.
Sources
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Utility Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
Scientists have no evidence of how the shot hole borer beetle first entered the United States, but suspect it came in on wooden packing materials from Vietnam. The “Polyphagous shot hole borer” (PSHB) (Euwallacea fornicatus) and the “Kuroshio shot hole borer” (KSHB) are now referred to collectively as the “Invasive Shot Hole Borer” (ISHB). This pest was first caught in California in 2003. PSHB is found in a currently limited range on the coast of California, from Los Angeles south to San Diego. It has also been found in Israel. This tiny beetle is the size of a sesame seed and is identified as a type of Ambrosia beetle of which there are 3,500 species, most of which partner with fungi to decompose dead trees. Female beetles make tunnels, or galleries, in the trunks and branches of host trees and lay their eggs inside. Males are much smaller, do not fly, and don’t leave the galleries.
When a female Ambrosia beetle finds a suitable tree, she chews a tunnel into the sapwood and “plants” a fungus as she digs. Ambrosia beetles have special pits or dents in their bodies (called mycangia) that are used to carry the spores of fungi. The fungus then grows into the tree’s wood and on the walls of the beetle galleries providing a fresh crop of fungal food for both PSHB and ISHB beetles. The relationship between the beetle and the fungus is called ‘symbiotic', meaning that these two very different species depend on each other. The fungus provides a ready source of food for the beetle and the beetle provides the fungus with a free ride to new trees.
Part of the reason this beetle is so destructive is that it has a huge appetite for the fungus. In fact, it has been known to attack plants in 58 different families. Many of these plants are important parts of the native California ecosystems, and others are planted widely across the U.S. in cities and neighborhoods. A few host species, like avocado and olive, are also important in agriculture. By 2010, hundreds of boxelders (Acer negundo) lining the streets in Long Beach, CA, were injured or killed by the beetle and had to be removed. The beetle then moved on to California sycamores (Platanus racemosa), killing thousands on streets, in yards, public parks, and wilderness areas.
The KSHB appeared south of Long Beach and it has killed over 180,000 willows in the Tijuana River Valley. The willows include: Weeping willow (Salix babylonica), Goodding's black willow (Salix gooddingii), and Red Willow (Salix laevigata). This area happens to coincide with a critical breeding area and habitat for a rare vireo (Vireonidae) and willow flycatcher (Empidonax traillii extimus). Both birds are listed as endangered species. In addition the loss of the willows shading the river affects all the aquatic organisms, crawdads, and fish because the water has become too hot for them to live in.
The ISHB has a wide plant palette. More than 360 tree species have been attacked and ISHB is able to reproduce in at least 62 species of plants and trees. This beetle does not eat the wood, it just bores into the tree, carrying a number of different fungi that cause Fusarium (Fusarium euwallaceae) dieback and in many cases, death. The borer attacks healthy trees because the fungi it carries needs the water and nutrients from living trees to grow. The beetle is able to reproduce in many tree species, but is repelled by others. For example, pines block them at the holes with resin and cherry species exude a juice that turns hard as amber. However, once the beetle is in the tree, nothing will work.
So far, PSHB has been found infesting trees in neighborhoods, avocado farms, and several public gardens. Because PSHB can attack so many different types of trees, California woodlands are also at risk as the beetle continues to spread.
In their native homes, ambrosia beetles usually only attack sick or dead trees. However, when they are accidentally moved to new habitats, they begin attacking healthy trees.
Affected Species
The beetle's first favorite species was avocado (Persea americana). The avocado trees suffer with wilt and branch dieback. However they seem to survive and still bear fruit. Their next most favorite species is the box elder, followed by sycamore, and currently the beetles are attacking English oak (Quercus robur), California live oak (Quercus agrifolia), and valley oak (Quercus lobata).
Treatments
Trimming diseased branches, then chipping and grinding the wood and covering the material to heat up in the sun, kills about 98% of the beetles. There are no other effective treatments. There are also no known trees that are resistant to the bacteria. However, science is close to finding a treatment process that might prevent the bacteria from causing death to the trees. Researchers are also working on a couple of insect predators, but testing such biological agents takes years.
Before a treatment is found, the undeterred shot hole borer will thrive in hotter cities with higher ozone pollution and carbon dioxide levels. They will also thrive in major storms and trees affected by impaired water quality. This will result in unknown tolls on wildlife and human health.
Before treatments and pest resistance provide a suitable treatment, scientists predict this pest will cause an epidemic as significant as Dutch elm disease and chestnut blight.
Sources
- American Public Gardens Association, Polyphagous Shot Hole Borer, 2012.
- Raver, Anne, “The Tiny Menace”, Landscape Architecture Magazine, March 2018.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Utility Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Trees and People
By Len Phillips
Trees are at the top of the plant kingdom and people are at the top of the animal kingdom. However, since we all evolved on the same planet, I wondered if people are more similar to trees than we care to admit?
For example, trees are superior survival organisms. They have grown on the earth for at least 400 million years, and people are superior survival organisms and have roamed the earth for at least 100 thousand years.
Throughout the planet, the goal of all living creatures is to survive and reproduce. The strategies to do so are programmed into a genetic code. In a tree, the genetic code is expressed as the tree's structure and function. Trees make seeds, bark, leaves, roots, and wood, all according to their genetic code. People also have a genetic code that dictates a person’s features, health, and personality in addition to structure and function. People make babies according to their genetic code.
Lets look at some other examples of our similarities:
Seed fertilization with trees occurs when male pollen is carried by insects to the female flower, or the pollen is dispersed by wind blowing the pollen to nearby female flowers. In people, if a woman’s egg meets up with a healthy male sperm on its way to the uterus, the process of creating a new life begins. Going one step further, a tree will produce much more pollen than is necessary for the few female flowers that will require pollination. A man will produce much more sperm than is necessary for the one female egg that will require fertilization.
However, not all the flowers on a tree and not all pollen will become fertile and develop seeds. Not all of a woman's eggs and not all of a man's sperm will create a baby. In both situations, the genetic material in the pollen and sperm combine with the female reproductive organs to create a new cell that will rapidly start dividing into a seed or baby that will contain the genetic characteristics of both parents.
During gestation in trees, seeds are being formed. A tree seed accumulates reserves of food and its fullest development is rich in carbohydrates, fats, proteins and growth hormones. The essential parts of all seeds are the embryo, the protective covering of the seed coat, and a reserve of food substances which may be stored in the cotyledons, hypocotyl, endosperm, or perisperm, depending on the tree species. All of this food, enclosure, and protection is supplied by the mother tree. This food reserve provides nourishment to push the growth of an embryonic tree, until it can survive on its own.
During a baby human's gestation, the rising levels of carbohydrates, fats, proteins, and growth hormones prepare the uterus to support a fertilized egg, and enclose the growing baby in an amniotic sac that surrounded the baby during gestation over the coming months. Humans begin cell division and infant development within the ovaries as soon as the sperm has made contact with the egg. The baby is protected within the womb of the mother as it grows with food supplied by the mother.
Gestation in trees is the time it takes for the seed to grow and ripen on the tree within a pod, fruit, or shell. When the seed is ripe, it has developed to a point where it can germinate and survive in the forest. Gestation is defined in a woman as the carrying of an embryo or fetus inside the uterus. When the baby is born it has developed to a point where it can survive with parental care.
Seed dispersal strategies for trees vary widely, from wind-driven seeds such as on a maple tree, to seeds falling on the ground beneath a nut tree, to seeds carried away by certain species of animals or birds such as a crabapple being eaten by a bird and the seeds are dropped some distance from the tree after passing through the bird. Seeds can be spread anywhere on the globe. When the tree seed falls close to the parent it grows and becomes part of a grove of trees. The groves can be found in locations that provide the ideal locations for the particular tree species growing in the forest.
A baby is born when it has developed to a point where it can survive outside of the womb. Unlike trees, people have babies that stay with the parents until they are old enough to leave their home and then they may wish to settle close to home or their mobility allows them to move anywhere on the globe. When the baby stays close to home it becomes part of a familly and many families create a village.
When tree seeds are being formed, most trees store food as a reserve within the seed itself. The food consists of starch, proteins, and oils. This food reserve provides nourishment to push the growth of an embryonic tree. When the seed imbibes water, hydrolytic enzymes are activated which break down these stored food resources into metabolically useful chemicals that will begin the growth process. There will be enough food to keep the embryonic tree growing until the primary leaves and roots begin photosynthesis and roots begin to gather nutrients and water. The embryonic tree then becomes a seedling growing on its own, with no assistance from its parents.
Human babies also store food from the mother, internally, within the baby’s body as it grows in the womb. When the growth and other conditions are just right, the birth process begins. The baby will have enough energy to tolerate the push down the mother’s birth canal until it is born. Then the baby will begin to grow under the external care of its parents, unlike the tree that will grow on its own.
Trees have one advantage over people. Besides growing from seeds, most trees can also survive through regeneration from stump or root sprouts. These sprouts start from dormant buds that formed during the growth process. When injuries, disease, or other types of disturbance occurs somewhere on the tree, sprouts begin to develop as a response. The sprouts will grow into full-sized trees.
People on the other hand, have advantages over trees. Invetro fertilization has been invented to create new human life that can be transferred to a woman. In addition, if growing conditions are not just right, people can move to a new location for more food, more safety, or a better climate. People can also seek shelter from bad weather.
One other point where we differ from trees is that plants can make their own food using energy from the sun so they can grow. People and animals have to kill and eat plants for their energy source so they can grow.
And all of this is just the similarities between trees and people at the beginning of life. Think about how trees and people grow, live, die, and communicate. Maybe mankind will read and understand our position in the world and develop a better appreciation for trees. If not, the trees will certainly out-live mankind.
Source
Wohlleben, Peter, The Hidden Life of Trees, Greystone Books, 2015.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Len Phillips
Trees are at the top of the plant kingdom and people are at the top of the animal kingdom. However, since we all evolved on the same planet, I wondered if people are more similar to trees than we care to admit?
For example, trees are superior survival organisms. They have grown on the earth for at least 400 million years, and people are superior survival organisms and have roamed the earth for at least 100 thousand years.
Throughout the planet, the goal of all living creatures is to survive and reproduce. The strategies to do so are programmed into a genetic code. In a tree, the genetic code is expressed as the tree's structure and function. Trees make seeds, bark, leaves, roots, and wood, all according to their genetic code. People also have a genetic code that dictates a person’s features, health, and personality in addition to structure and function. People make babies according to their genetic code.
Lets look at some other examples of our similarities:
Seed fertilization with trees occurs when male pollen is carried by insects to the female flower, or the pollen is dispersed by wind blowing the pollen to nearby female flowers. In people, if a woman’s egg meets up with a healthy male sperm on its way to the uterus, the process of creating a new life begins. Going one step further, a tree will produce much more pollen than is necessary for the few female flowers that will require pollination. A man will produce much more sperm than is necessary for the one female egg that will require fertilization.
However, not all the flowers on a tree and not all pollen will become fertile and develop seeds. Not all of a woman's eggs and not all of a man's sperm will create a baby. In both situations, the genetic material in the pollen and sperm combine with the female reproductive organs to create a new cell that will rapidly start dividing into a seed or baby that will contain the genetic characteristics of both parents.
During gestation in trees, seeds are being formed. A tree seed accumulates reserves of food and its fullest development is rich in carbohydrates, fats, proteins and growth hormones. The essential parts of all seeds are the embryo, the protective covering of the seed coat, and a reserve of food substances which may be stored in the cotyledons, hypocotyl, endosperm, or perisperm, depending on the tree species. All of this food, enclosure, and protection is supplied by the mother tree. This food reserve provides nourishment to push the growth of an embryonic tree, until it can survive on its own.
During a baby human's gestation, the rising levels of carbohydrates, fats, proteins, and growth hormones prepare the uterus to support a fertilized egg, and enclose the growing baby in an amniotic sac that surrounded the baby during gestation over the coming months. Humans begin cell division and infant development within the ovaries as soon as the sperm has made contact with the egg. The baby is protected within the womb of the mother as it grows with food supplied by the mother.
Gestation in trees is the time it takes for the seed to grow and ripen on the tree within a pod, fruit, or shell. When the seed is ripe, it has developed to a point where it can germinate and survive in the forest. Gestation is defined in a woman as the carrying of an embryo or fetus inside the uterus. When the baby is born it has developed to a point where it can survive with parental care.
Seed dispersal strategies for trees vary widely, from wind-driven seeds such as on a maple tree, to seeds falling on the ground beneath a nut tree, to seeds carried away by certain species of animals or birds such as a crabapple being eaten by a bird and the seeds are dropped some distance from the tree after passing through the bird. Seeds can be spread anywhere on the globe. When the tree seed falls close to the parent it grows and becomes part of a grove of trees. The groves can be found in locations that provide the ideal locations for the particular tree species growing in the forest.
A baby is born when it has developed to a point where it can survive outside of the womb. Unlike trees, people have babies that stay with the parents until they are old enough to leave their home and then they may wish to settle close to home or their mobility allows them to move anywhere on the globe. When the baby stays close to home it becomes part of a familly and many families create a village.
When tree seeds are being formed, most trees store food as a reserve within the seed itself. The food consists of starch, proteins, and oils. This food reserve provides nourishment to push the growth of an embryonic tree. When the seed imbibes water, hydrolytic enzymes are activated which break down these stored food resources into metabolically useful chemicals that will begin the growth process. There will be enough food to keep the embryonic tree growing until the primary leaves and roots begin photosynthesis and roots begin to gather nutrients and water. The embryonic tree then becomes a seedling growing on its own, with no assistance from its parents.
Human babies also store food from the mother, internally, within the baby’s body as it grows in the womb. When the growth and other conditions are just right, the birth process begins. The baby will have enough energy to tolerate the push down the mother’s birth canal until it is born. Then the baby will begin to grow under the external care of its parents, unlike the tree that will grow on its own.
Trees have one advantage over people. Besides growing from seeds, most trees can also survive through regeneration from stump or root sprouts. These sprouts start from dormant buds that formed during the growth process. When injuries, disease, or other types of disturbance occurs somewhere on the tree, sprouts begin to develop as a response. The sprouts will grow into full-sized trees.
People on the other hand, have advantages over trees. Invetro fertilization has been invented to create new human life that can be transferred to a woman. In addition, if growing conditions are not just right, people can move to a new location for more food, more safety, or a better climate. People can also seek shelter from bad weather.
One other point where we differ from trees is that plants can make their own food using energy from the sun so they can grow. People and animals have to kill and eat plants for their energy source so they can grow.
And all of this is just the similarities between trees and people at the beginning of life. Think about how trees and people grow, live, die, and communicate. Maybe mankind will read and understand our position in the world and develop a better appreciation for trees. If not, the trees will certainly out-live mankind.
Source
Wohlleben, Peter, The Hidden Life of Trees, Greystone Books, 2015.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Trees with Tales #79
By Len Phillips
The Tree
Quercus rubra, Northern Red Oak, also known as red oak or champion oak. The “red oak” name comes from the red color of the midrib and veins on leaves as well as the dark red autumn color. The tree has a brown acorn. Red oak is grown in cities because, unlike other oaks, it does not develop a taproot that is difficult to transplant. It prefers sandy loam soils and tolerates the polluted air in our cities.
The Tales
The northern red oak is the state tree of New Jersey and the provincial tree of Prince Edward Island. The trees may live up to 500 years of age. These trees grow straight and tall, up to 140 feet (43 m) tall and 40 inches (50–100 cm) in trunk diameter. Under optimal conditions and full sun, northern red oak is fast growing and a 10-year-old tree can be 16 – 20 ft (5 – 6 m) tall. The northern red oak is one of the most important oaks for timber production in North America. Quality red oak is of high value as lumber and veneer, while defective logs are excellent sources of firewood.
The northern red oak is also known for its trait of holding on to its leaves all through the winter while almost all other deciduous trees go completely bare. The retaining of dead leaves and other plant parts, is called marcescence (pronounced mar-ses-cents). Marcescence is most common on red oak but may also be occasionally found on other deciduous trees such as beech (Fagus) and hornbeam (Carpinus) and it almost always exists in palms. Marcescent leaves start in autumn with the development of their abscission layer, separating the leaf from the twig, but will not finish the separation until the spring. The base of the petiole remains alive over the winter and this results in the dead leaves clinging to the tree all winter long. Many trees may also have marcescent leaves in seasons when an early freeze has killed the leaves before the abscission layer has completed development. In all these situations the brown leaves remain on the tree until the new leaves emerge the following spring.
To understand why marcescence might develop, consider the evolutionary history of trees. Evergreens were the first trees on the planet. Evergreens had an advantage because they had the maximum time in a year for the leaves to grow and remain photosynthetic. Populations of these earliest evergreen trees eventually encountered changing climates and soils as they expanded their range. As evolution continued, trees began to develop different ways of growing and shedding their leaves when the sunlight declined in winter. This is when the broad-leafed hardwoods evolved.
Every leaf has a life span and will fade and fall from the tree at some regular interval. However, there is great variation in the timing of this leaf drop. At one end of the spectrum are the evergreens. Although they appear to be fully leafed all of the time, evergreen leaves are not always green and some needles die, turn brown, and fall from the tree after two or three years.
On the other end of the spectrum, are the deciduous or hardwood trees, which usually drop their leaves every autumn. In autumn, the cells at the interface between the twig and the end of the leaf stem release enzymes that form the abscission layer which separates the leaf from the vascular bundles, allowing the leaf to fall free. Leaf drop benefits deciduous trees by reducing water loss in winter which allows them to efficiently develop leaves the following spring. The leaf drop in autumn also allows broad-leafed trees to reduce frost, snow, and ice damage during unfavorable weather while using their broad leaves to increase their photosynthetic efficiency during the growing season.
In between the evergreens and broad-leafed trees is the third, very minor class of trees, those with marcescence. The leaves of these trees die in autumn, but many leaves do not fall to the ground when they die because the abscission layer remains alive. These leaves do not break off until mechanical forces such as the wind cause the dry and brittle petioles to snap. Scientists do not know whether marcescence provides a detriment or competitive benefit to these trees.
The fact is, nobody really knows the reason for marcescence. Scientists do know how it occurs but can only speculate on why it occurs. It is also important to note, that marcescence does not happen every year to most trees, and it does not happen to all red oak trees. While scientists agree that marcescence is a juvenile trait, most commonly, but not always observed on young trees and on lower branches, there is considerable debate about why red oaks would seem to be deciduous in all other aspects except that some trees experience marcescence.
Botanists have speculated several reasons for why marcescence occurs:
Regardless the reason for marcescent leaves, when growth begins in spring the expanding buds will push the old leaves off and new leaves will appear on the branches. Until that happens, enjoy the waving brown leaves and the texture they add to the forest and the winter landscapes.
Appreciate the Northern Red Oak tree not only for its marcescent leaves but also for its large size growing in our cities and the beautiful, hard, wood from its lumber.
Sources
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Len Phillips
The Tree
Quercus rubra, Northern Red Oak, also known as red oak or champion oak. The “red oak” name comes from the red color of the midrib and veins on leaves as well as the dark red autumn color. The tree has a brown acorn. Red oak is grown in cities because, unlike other oaks, it does not develop a taproot that is difficult to transplant. It prefers sandy loam soils and tolerates the polluted air in our cities.
The Tales
The northern red oak is the state tree of New Jersey and the provincial tree of Prince Edward Island. The trees may live up to 500 years of age. These trees grow straight and tall, up to 140 feet (43 m) tall and 40 inches (50–100 cm) in trunk diameter. Under optimal conditions and full sun, northern red oak is fast growing and a 10-year-old tree can be 16 – 20 ft (5 – 6 m) tall. The northern red oak is one of the most important oaks for timber production in North America. Quality red oak is of high value as lumber and veneer, while defective logs are excellent sources of firewood.
The northern red oak is also known for its trait of holding on to its leaves all through the winter while almost all other deciduous trees go completely bare. The retaining of dead leaves and other plant parts, is called marcescence (pronounced mar-ses-cents). Marcescence is most common on red oak but may also be occasionally found on other deciduous trees such as beech (Fagus) and hornbeam (Carpinus) and it almost always exists in palms. Marcescent leaves start in autumn with the development of their abscission layer, separating the leaf from the twig, but will not finish the separation until the spring. The base of the petiole remains alive over the winter and this results in the dead leaves clinging to the tree all winter long. Many trees may also have marcescent leaves in seasons when an early freeze has killed the leaves before the abscission layer has completed development. In all these situations the brown leaves remain on the tree until the new leaves emerge the following spring.
To understand why marcescence might develop, consider the evolutionary history of trees. Evergreens were the first trees on the planet. Evergreens had an advantage because they had the maximum time in a year for the leaves to grow and remain photosynthetic. Populations of these earliest evergreen trees eventually encountered changing climates and soils as they expanded their range. As evolution continued, trees began to develop different ways of growing and shedding their leaves when the sunlight declined in winter. This is when the broad-leafed hardwoods evolved.
Every leaf has a life span and will fade and fall from the tree at some regular interval. However, there is great variation in the timing of this leaf drop. At one end of the spectrum are the evergreens. Although they appear to be fully leafed all of the time, evergreen leaves are not always green and some needles die, turn brown, and fall from the tree after two or three years.
On the other end of the spectrum, are the deciduous or hardwood trees, which usually drop their leaves every autumn. In autumn, the cells at the interface between the twig and the end of the leaf stem release enzymes that form the abscission layer which separates the leaf from the vascular bundles, allowing the leaf to fall free. Leaf drop benefits deciduous trees by reducing water loss in winter which allows them to efficiently develop leaves the following spring. The leaf drop in autumn also allows broad-leafed trees to reduce frost, snow, and ice damage during unfavorable weather while using their broad leaves to increase their photosynthetic efficiency during the growing season.
In between the evergreens and broad-leafed trees is the third, very minor class of trees, those with marcescence. The leaves of these trees die in autumn, but many leaves do not fall to the ground when they die because the abscission layer remains alive. These leaves do not break off until mechanical forces such as the wind cause the dry and brittle petioles to snap. Scientists do not know whether marcescence provides a detriment or competitive benefit to these trees.
The fact is, nobody really knows the reason for marcescence. Scientists do know how it occurs but can only speculate on why it occurs. It is also important to note, that marcescence does not happen every year to most trees, and it does not happen to all red oak trees. While scientists agree that marcescence is a juvenile trait, most commonly, but not always observed on young trees and on lower branches, there is considerable debate about why red oaks would seem to be deciduous in all other aspects except that some trees experience marcescence.
Botanists have speculated several reasons for why marcescence occurs:
- Forest shade hinders short trees because the blocked sunlight slows the abscission process in autumn, however, marcescence also occurs on trees in full sun.
- Sometimes early cold weather or frosts in autumn may interrupt the abscission process and kills the leaves before they can drop off, but this does not always happen.
- The tree has learned that buds hidden by clusters of dead leaves do not get eaten by animals and thus live to become new shoots and leaves in the spring. The dead, dry leaves make the twigs less nutritious and less palatable to animals, but not always.
- The protein content of some twigs is about equal to the leaves; however, the lignin content is a lot higher in the dry leaves. This is an interesting fact, but inconclusive about a relationship to marcescence.
- Marcescent leaves may protect some species from water or temperature stress, but not all leaves on the tree are marcescent.
- The persistent leaves might provide some frost protection for buds to assist in survival over winter, but why does this trait disappear when the tree gets older?
- The marcescent susceptible species are still evolving and will become fully deciduous trees from their evergreen past but have not yet mastered being deciduous, but this does not explain the annual inconsistency.
- Diseases or pests have killed the leaves before they can finish the abscission layer but this does not answer the annual inconsistency.
- Cold autumn temperature slows the photosynthetic process before the tree can finish the abscission layer, but not always.
- Some marcescent leaves have been confirmed to improve survival, help the tree's water balance, and protect the tree from cold injury, but complete leaf drop would be better.
- The retained leaves, particularly on young trees and the lower branches on bigger trees, is an effective means of trapping snow, leading to sheltered branches and more moisture at the base of the tree when growth resumes in the spring, but there is no advantage to marcescence.
- The dried leaves discourage deer and other animals wanting to eat the nutritious buds hidden by the leaves. Dead, dry leaves make the twigs less nutritious and less palatable.
- Marcescent leaves provide shelter for wintering birds as they perch among the rattling leaves, away from winter’s wind. This may be nice but there is no conclusion related to marcescence.
- Sometimes leaves persist only on scattered branches, but there is no consistency.
- Some ecologists suggest that marcescence provides an advantage for trees growing on dry, cold, and infertile sites. The retained leaves means a delay in the decomposition of the leaves and that dropping them in spring delivers organic material at a time when it is most needed by the growing parent tree. Even small amounts at the right time could shift the competitive advantage toward these species on poor sites. But there is no consistency with this fact.
- According to native American lore, marcescence first began when an Indian princess hid in a red oak tree during a raid by an enemy tribe and escaped from being captured. The red oak was celebrated every year thereafter.
Regardless the reason for marcescent leaves, when growth begins in spring the expanding buds will push the old leaves off and new leaves will appear on the branches. Until that happens, enjoy the waving brown leaves and the texture they add to the forest and the winter landscapes.
Appreciate the Northern Red Oak tree not only for its marcescent leaves but also for its large size growing in our cities and the beautiful, hard, wood from its lumber.
Sources
- Gilman, Edward F. and Dennis G. Watson, Quercus rubra, Northern Red Oak, Forest Service, October 1994
- J. Frank Schmidt & Son Nursery fact sheet
- Missouri Botanical Garden, “Quercus rubra”, Plant Finder, 2018.
- Wikipedia, “Quercus rubra”, 3 April 2018
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
A New Tree Container
By Len Phillips
Do you purchase your new trees in containers, balled and burlapped, or bare root? If it is in containers, are the trees planted in the container just for the purpose of sales or have the trees been growing in progressively larger containers for several years? Chances are the containerized trees have been growing in the same container for a few months or years so as a buyer, you should be cautious with your purchase and look at the roots of each tree.
As we all know, circling and girdling tree roots are quite common from trees being grown in plastic containers. This is because plastic containers are designed to hold dirt and tree roots, but they are not designed for growing trees for a couple of years or more. In the plastic containers, as the roots grow, they will circle the container and eventually girdle tree because the roots have wrapped round the trunk of the tree and they will weakened it in time.
Besides the confinement of the growing roots, problems also occur because the flow of water and nutrients is restricted or flushed through the container, which also leads to the decline in the health of the tree. To make matters worse, the girdling root problem will not correct itself once the tree is removed from the container and installed in the landscape. The tree will be lacking vigor and fast growth for quite a few years, if it even survives.
Fortunately, a new generation of containers are coming into the market that have been developed specifically for growing healthy trees. After a considerable amount of time using different materials and designs for different containers that would grow trees without the root problems, researchers developed a new type of fabric container made from recycled water bottles blended with different types of natural recycled fibers.
This planting container was designed with growing trees in mind. These containers are made to be the most sustainable growing container available in the market today. The container is long lasting and durable while encouraging trees to develop strong, lateral, dense, fibrous roots.
The container fabrics are ultra-violet resistant, and are manufactured in a safe and clean environment. They are made of the recycled plastic, #1 PETE. PETE or PET also known as polyethylene terephthalate, is the product used in the vast majority of disposable beverage, drinking water bottles, and food containers. To the best of the company's knowledge, not one drop of new oil, petroleum, or fossil fuel is used in the container's creation and they do not leach toxins. This new planting container is made specifically as an in-ground, long-duration growing container.
These fabric containers provide a breathable healthy growing environment. Fabric containers, unlike traditional black plastic containers, allow water and air to flow through its structure nourishing the root of the tree. The natural fibers in the fabric allow the water and nutrients to be drawn to the tree when planted in the ground. It also does not allow the tree roots to circle once they meet the resistance of the wall of the container. Instead, through a couple of different means, the fabric causes the tree to send out new fibrous roots rather than circle and harm the tree. Root Pouch is the company that developed this process to use both recycled plastic fibers along with natural fibers, vegetable fibers, or bamboo fibers.
These natural fibers mixed into the netting of the fabric will retain moisture much more evenly around the container. While allowing the fabric to breath, the fibers also help to cool down the tree in summer. In the winter, the same fibers, allow the heat given off by trees to be contained and keep the tree warmer. The fabric containers when set can-tight (containers touching each other) will also exchange heat between them.
These fabric containers keep trees healthy by letting in water and nutrients and letting out excess water so the roots can breathe and grow. The fabric will also have different tensile strengths depending on the density of the fibers and plastic. Root Pouch makes seven different densities of fabric depending on the container strength that is required. Regardless of the density, the containers are guaranteed to always hold the weight that is required for that size of container.
If you find these containers are what you need for growing healthy trees, simply specify that you want your trees grown in containers made with natural fibers and recycled plastic.
Sources
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Len Phillips
Do you purchase your new trees in containers, balled and burlapped, or bare root? If it is in containers, are the trees planted in the container just for the purpose of sales or have the trees been growing in progressively larger containers for several years? Chances are the containerized trees have been growing in the same container for a few months or years so as a buyer, you should be cautious with your purchase and look at the roots of each tree.
As we all know, circling and girdling tree roots are quite common from trees being grown in plastic containers. This is because plastic containers are designed to hold dirt and tree roots, but they are not designed for growing trees for a couple of years or more. In the plastic containers, as the roots grow, they will circle the container and eventually girdle tree because the roots have wrapped round the trunk of the tree and they will weakened it in time.
Besides the confinement of the growing roots, problems also occur because the flow of water and nutrients is restricted or flushed through the container, which also leads to the decline in the health of the tree. To make matters worse, the girdling root problem will not correct itself once the tree is removed from the container and installed in the landscape. The tree will be lacking vigor and fast growth for quite a few years, if it even survives.
Fortunately, a new generation of containers are coming into the market that have been developed specifically for growing healthy trees. After a considerable amount of time using different materials and designs for different containers that would grow trees without the root problems, researchers developed a new type of fabric container made from recycled water bottles blended with different types of natural recycled fibers.
This planting container was designed with growing trees in mind. These containers are made to be the most sustainable growing container available in the market today. The container is long lasting and durable while encouraging trees to develop strong, lateral, dense, fibrous roots.
The container fabrics are ultra-violet resistant, and are manufactured in a safe and clean environment. They are made of the recycled plastic, #1 PETE. PETE or PET also known as polyethylene terephthalate, is the product used in the vast majority of disposable beverage, drinking water bottles, and food containers. To the best of the company's knowledge, not one drop of new oil, petroleum, or fossil fuel is used in the container's creation and they do not leach toxins. This new planting container is made specifically as an in-ground, long-duration growing container.
These fabric containers provide a breathable healthy growing environment. Fabric containers, unlike traditional black plastic containers, allow water and air to flow through its structure nourishing the root of the tree. The natural fibers in the fabric allow the water and nutrients to be drawn to the tree when planted in the ground. It also does not allow the tree roots to circle once they meet the resistance of the wall of the container. Instead, through a couple of different means, the fabric causes the tree to send out new fibrous roots rather than circle and harm the tree. Root Pouch is the company that developed this process to use both recycled plastic fibers along with natural fibers, vegetable fibers, or bamboo fibers.
These natural fibers mixed into the netting of the fabric will retain moisture much more evenly around the container. While allowing the fabric to breath, the fibers also help to cool down the tree in summer. In the winter, the same fibers, allow the heat given off by trees to be contained and keep the tree warmer. The fabric containers when set can-tight (containers touching each other) will also exchange heat between them.
These fabric containers keep trees healthy by letting in water and nutrients and letting out excess water so the roots can breathe and grow. The fabric will also have different tensile strengths depending on the density of the fibers and plastic. Root Pouch makes seven different densities of fabric depending on the container strength that is required. Regardless of the density, the containers are guaranteed to always hold the weight that is required for that size of container.
If you find these containers are what you need for growing healthy trees, simply specify that you want your trees grown in containers made with natural fibers and recycled plastic.
Sources
- Fromm, Ashley, “Root Pouch”, Nursery Management, March 2018
- Root Pouch website
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Cultivars, Nativars and Clones
Edited by Len Phillips
Often we will use the terms “cultivars” and “clones” interchangeably. As you will see there is a difference between these and other closely related terms that professional arborists should be aware of. Clones may not be cultivars, and cultivars may not be clones, but nativars can be cultivars. Few, if any, of our currently popular trees are clones, but with increased success in biotechnology (tissue culture), some will certainly be cloned in the future. All it takes to make a cultivar a clone is naming it a clone and growing it on its own roots.
Definitions
Clones
A clone consists of a group of plants of absolute genetic uniformity and is the ultimate in monoculture. Commercial farmers extensively utilize clones and plant large monocultures with minimal genetic diversity. One of the principal reasons commercial farmers utilize genetic uniformity is that most commercial crops are the products of generations of genetic research, bred and selected to be resistant to major pests and specific herbicides, are adapted to specific localities, and/or are drought and heat tolerant. Commercial farmers plant clonal monocultures to capture the advertised superiority of these plants and uniformity in sowing, culture, and harvesting. Also, as most agricultural plants are annuals, when pest problems do arise, an army of scientists are ready to battle the pest with new genetic combinations, chemicals, or bio-control agents.
The city forester is not as fortunate as the commercial farmer. Few trees currently grown and sold as clones in the nursery trade have been purposely developed and thoroughly tested for pest resistance. The trees must endure for decades, often in difficult situations where environmental and biotic stresses are continually changing. The development of a new “replacement” for a clone, with similar characteristics of growth and pest resistance may require decades of research. Some of the clones now available for city planting were originally selected for certain aesthetics, propagated by budding and grafting, and marketed as named cultivars .
Cultivars
The use of seedling understock, whether of the same or a related species, introduces an element of diversity that might affect tree performance. Tree monocultures may only pose major problems when the numbers of trees are large and the area occupied by the trees is restricted. In other words, twenty to fifty trees of a single species, or even a single clone, planted along a few blocks of city streets do not constitute a “dangerous” monoculture. If 75% of the trees in the city were the same cultivar, that might become a problem.
Advantages of Cultivars
The most obvious advantage of cultivars is their reliability, especially those cultivars that have been in the nursery trade for 20 years or more. They can be counted on to develop the form, color, and growth rate for which they were selected. Their longevity in the trade and their widespread planting has provided the testing necessary to determine both their good and bad characteristics. The urban tree planter knows what to expect of such trees.
One other characteristic of most cultivars, especially those that had been traditionally propagated by budding and grafting, is their genetic capacity for strong wound compartmentalization. Studies have shown that every cultivar tested, in a wide range of genera and species, were strong compartmentalizers. The conclusion was made because the grafting and budding process constituted an inadvertent “screening” and only strong compartmentalizing trees would be amenable to long-term commercial propagation by these techniques. Some of the cultivars formerly propagated by budding and grafting are now propagated on their own roots and have retained this important trait.
Uncertainties of Cultivars
The major uncertainties of cultivars relate to the possibility of long-term graft incompatibility. Recent research has determined that graft compatibility is dependent on the similarity of stock and scion in cambial peroxidase enzymes, which mediate the production of lignin. In Castanea mollissima, Quercus rubra, and Acer rubrum graft incompatibility is a major problem because there is considerable tree-to-tree variability in enzyme patterns. On the other hand, Acer saccharum, Acer platanoides, and Gleditsia triacanthos appeared to be quite uniform in enzyme pattern and no graft incompatibility has been reported.
Limited work on Cornus, Fagus, Fraxinus, and Koelreuteria indicated that graft incompatibility could cause problems in these genera. For those genera and species that are difficult to propagate from cultivars or by micro-propagation, the careful matching of enzyme patterns of stock and scion will produce graft-compatible combinations.
However, there are still many species that have not been studied and the city forester should be cautious in their use of new grafted cultivars of Celtis, Maclura, and Tilia.
Conclusion
It is recommended that you plant clones and cultivars that have proven their reliability. Use, somewhat cautiously and on a trial basis, some of the untested new cultivars of “unfamiliar” species or genera. These newer introductions have been developed through scientific research and have been selected for survival traits such as pest resistance or salt tolerance, but should be tested in your region for trial.
For uniformity, use seedlings of known geographic origin (or, in the case of exotics like Tilia cordata, from proven seed sources) so the plants will be able to tolerate the general climatic conditions in your area. For diversity, use the best clones, cultivars, and seedlings of many species and genera distributed throughout the city or as mixes of individual trees.
For the education of the next generation, plant a catalpa, a hickory, a horse-chestnut, a sassafras, and even a thorny honeylocust in park areas that can and should be used to stimulate an interest in the diversity of nature.
Source
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
Often we will use the terms “cultivars” and “clones” interchangeably. As you will see there is a difference between these and other closely related terms that professional arborists should be aware of. Clones may not be cultivars, and cultivars may not be clones, but nativars can be cultivars. Few, if any, of our currently popular trees are clones, but with increased success in biotechnology (tissue culture), some will certainly be cloned in the future. All it takes to make a cultivar a clone is naming it a clone and growing it on its own roots.
Definitions
- Cultivar or Grafted Cultivar: Cultivars are named selections. In landscape trees, cultivars are generally propagated by some asexual means, be it cuttings, budding, grafts, divisions, or tissue culture from the preferred tree onto seedling rootstock of the same species. The above ground portion of all trees will be genetically identical, but there will be genetic variability among rootstocks. What you lose with these genetically identical plants is diversity. Over a series of generations, if the plants can not reproduce, you decrease the gene pool and the ability of the population to adapt to change.
- Nativars: Nativars are cultivated varieties of native trees. They are usually a selection from a native tree that has a unique form or a unique color in autumn, or resistance to pests, diseases, and pollutants to the native tree. Nativars are propagated as cuttings or some other asexual means.
- Natives: Native trees are those growing in the wild and in proximity to the nursery growing native trees. Nurseries collect native tree seedlings from a local forest and are to be sold to local customers only. Natives are propagated by seed.
- Clone: A clone is propagated by asexual propagation (rooted cuttings or micro propagation) from a single tree and grown on its own roots. All members of the clone will be genetically identical from root tip to apical meristem. More often than not, a cultivar name will have been given to the clone.
- Seedlings: These plants are derived from seed collected from a single tree. Granted that most landscape trees are naturally cross-pollinated and are highly heterozygous (dissimilar pairs of genes for any hereditary characteristic), the progeny from a single parent tree will be more genetically uniform than seedlings derived from several parent trees.
- Seed-Orchard Seedlings: Seedlings derived from pollination among trees selected for certain desirable attributes (such as pest resistance) and propagated and planted in a “seed orchard”, specifically for seed production. There will be a high degree of genetic uniformity with regard to the traits that constituted the original selection criteria but, still, a reasonable amount of genetic diversity.
- Provenance Seedlings: Seedlings coming from native trees in a particular geographic area, assuring that the seedlings will be adaptable to the general climatic conditions pertaining to that area.
- Mixed Seedlings: Seedlings of unknown geographic origin with unknown adaptability or seedlings of different known provenance. This potentially high level of diversity may occur among the products of a single nursery and will nearly always occur when seedlings are obtained from several different nurseries.
Clones
A clone consists of a group of plants of absolute genetic uniformity and is the ultimate in monoculture. Commercial farmers extensively utilize clones and plant large monocultures with minimal genetic diversity. One of the principal reasons commercial farmers utilize genetic uniformity is that most commercial crops are the products of generations of genetic research, bred and selected to be resistant to major pests and specific herbicides, are adapted to specific localities, and/or are drought and heat tolerant. Commercial farmers plant clonal monocultures to capture the advertised superiority of these plants and uniformity in sowing, culture, and harvesting. Also, as most agricultural plants are annuals, when pest problems do arise, an army of scientists are ready to battle the pest with new genetic combinations, chemicals, or bio-control agents.
The city forester is not as fortunate as the commercial farmer. Few trees currently grown and sold as clones in the nursery trade have been purposely developed and thoroughly tested for pest resistance. The trees must endure for decades, often in difficult situations where environmental and biotic stresses are continually changing. The development of a new “replacement” for a clone, with similar characteristics of growth and pest resistance may require decades of research. Some of the clones now available for city planting were originally selected for certain aesthetics, propagated by budding and grafting, and marketed as named cultivars .
Cultivars
The use of seedling understock, whether of the same or a related species, introduces an element of diversity that might affect tree performance. Tree monocultures may only pose major problems when the numbers of trees are large and the area occupied by the trees is restricted. In other words, twenty to fifty trees of a single species, or even a single clone, planted along a few blocks of city streets do not constitute a “dangerous” monoculture. If 75% of the trees in the city were the same cultivar, that might become a problem.
Advantages of Cultivars
The most obvious advantage of cultivars is their reliability, especially those cultivars that have been in the nursery trade for 20 years or more. They can be counted on to develop the form, color, and growth rate for which they were selected. Their longevity in the trade and their widespread planting has provided the testing necessary to determine both their good and bad characteristics. The urban tree planter knows what to expect of such trees.
One other characteristic of most cultivars, especially those that had been traditionally propagated by budding and grafting, is their genetic capacity for strong wound compartmentalization. Studies have shown that every cultivar tested, in a wide range of genera and species, were strong compartmentalizers. The conclusion was made because the grafting and budding process constituted an inadvertent “screening” and only strong compartmentalizing trees would be amenable to long-term commercial propagation by these techniques. Some of the cultivars formerly propagated by budding and grafting are now propagated on their own roots and have retained this important trait.
Uncertainties of Cultivars
The major uncertainties of cultivars relate to the possibility of long-term graft incompatibility. Recent research has determined that graft compatibility is dependent on the similarity of stock and scion in cambial peroxidase enzymes, which mediate the production of lignin. In Castanea mollissima, Quercus rubra, and Acer rubrum graft incompatibility is a major problem because there is considerable tree-to-tree variability in enzyme patterns. On the other hand, Acer saccharum, Acer platanoides, and Gleditsia triacanthos appeared to be quite uniform in enzyme pattern and no graft incompatibility has been reported.
Limited work on Cornus, Fagus, Fraxinus, and Koelreuteria indicated that graft incompatibility could cause problems in these genera. For those genera and species that are difficult to propagate from cultivars or by micro-propagation, the careful matching of enzyme patterns of stock and scion will produce graft-compatible combinations.
However, there are still many species that have not been studied and the city forester should be cautious in their use of new grafted cultivars of Celtis, Maclura, and Tilia.
Conclusion
It is recommended that you plant clones and cultivars that have proven their reliability. Use, somewhat cautiously and on a trial basis, some of the untested new cultivars of “unfamiliar” species or genera. These newer introductions have been developed through scientific research and have been selected for survival traits such as pest resistance or salt tolerance, but should be tested in your region for trial.
For uniformity, use seedlings of known geographic origin (or, in the case of exotics like Tilia cordata, from proven seed sources) so the plants will be able to tolerate the general climatic conditions in your area. For diversity, use the best clones, cultivars, and seedlings of many species and genera distributed throughout the city or as mixes of individual trees.
For the education of the next generation, plant a catalpa, a hickory, a horse-chestnut, a sassafras, and even a thorny honeylocust in park areas that can and should be used to stimulate an interest in the diversity of nature.
Source
- Adams Garden, “Dealing with Cultivars and Clones”, Native Plants with Adams Garden, 2012.
- Hansen, Jolene, “Natives Vs Nativars”, Nursery Management, March 2018.
- Santamour, Frank S., Jr., “Uniformity and Common Sense”, METRIA 7 Proceedings, 1990.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award 0.5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.