Seminar #65 from Online Seminars for Municipal Arborists – November / December 2015
Sections
Click on the green words for more information
Sections
Click on the green words for more information
Tips from the Field
Dealing with Persistent Drought
By Mark Smith
How do we deal with a drought that lasts for years?
In 2009, we wrote about dealing with drought from the perspective that such a condition is usually temporary. In Texas, while we did have plentiful rain this spring, we are still feeling the impacts of the 2011 drought – four years later! This dry spell is not over.
On the surface, trees appear to be fairly durable during a drought, but there’s more going on than meets the eye. As soils dry out, feeder roots die and the tree’s ability to absorb and transport nutrients is compromised. As photosynthesis slows, the tree stops manufacturing food and begins to draw on stored energy. The leaves wilt, scorch, and begin to drop prematurely. As the tree canopy thins, cracks appear on the trunk and on branches, and suckers form at the base of the tree. Insects and diseases find the tree, now in a vulnerable state, to be an easy target and their attacks speed up the decline. Unfortunately, many of these symptoms go unnoticed until the following season, when stag-horning appears, dead and weakened branches fall, pests and parasites get established, and the decline becomes very evident.
On the surface, trees appear to be fairly durable during a drought, but there's more going on than meets the eye. As soils dry out, feeder roots die and the tree's ability to absorb and transport nutrients is compromised. As photosynthesis slows, the tree stops manufacturing food and begins to draw on stored energy. The leaves wilt, scorch, and begin to drop prematurely. As the tree canopy thins, cracks appear on the trunk and on branches, and suckers form at the base of the tree. Insects and diseases find the tree, now in a vulnerable state, to be an easy target and their attacks speed up the decline. Unfortunately, many of these symptoms go unnoticed until the following season, when stag-horning appears, dead and weakened branches fall, pests and parasites get established, and the decline becomes very evident.
Preventing Drought Damage
As arborists, we can’t prevent droughts but we can manage tree care to minimize the damage drought causes. There is a persistent myth that tree roots penetrate soil deeply enough to find adequate water even in times of drought. Not true! For most trees, the bulk of their roots are in the top 8”-18” (20-45 cm) of soil, making them highly susceptible to changes in soil moisture. Consequently, most preventative measures are best focused in and around the root zone.
Steps you can take to minimize drought damage include:
Watering During droughts, water for personal use takes precedence over outdoor use, resulting in restrictions on outdoor watering. With less water to go around, it can be challenging to ensure that trees receive an adequate share under such conditions. Here are some steps to consider:
Dealing with Persistent Drought
By Mark Smith
How do we deal with a drought that lasts for years?
In 2009, we wrote about dealing with drought from the perspective that such a condition is usually temporary. In Texas, while we did have plentiful rain this spring, we are still feeling the impacts of the 2011 drought – four years later! This dry spell is not over.
On the surface, trees appear to be fairly durable during a drought, but there’s more going on than meets the eye. As soils dry out, feeder roots die and the tree’s ability to absorb and transport nutrients is compromised. As photosynthesis slows, the tree stops manufacturing food and begins to draw on stored energy. The leaves wilt, scorch, and begin to drop prematurely. As the tree canopy thins, cracks appear on the trunk and on branches, and suckers form at the base of the tree. Insects and diseases find the tree, now in a vulnerable state, to be an easy target and their attacks speed up the decline. Unfortunately, many of these symptoms go unnoticed until the following season, when stag-horning appears, dead and weakened branches fall, pests and parasites get established, and the decline becomes very evident.
On the surface, trees appear to be fairly durable during a drought, but there's more going on than meets the eye. As soils dry out, feeder roots die and the tree's ability to absorb and transport nutrients is compromised. As photosynthesis slows, the tree stops manufacturing food and begins to draw on stored energy. The leaves wilt, scorch, and begin to drop prematurely. As the tree canopy thins, cracks appear on the trunk and on branches, and suckers form at the base of the tree. Insects and diseases find the tree, now in a vulnerable state, to be an easy target and their attacks speed up the decline. Unfortunately, many of these symptoms go unnoticed until the following season, when stag-horning appears, dead and weakened branches fall, pests and parasites get established, and the decline becomes very evident.
Preventing Drought Damage
As arborists, we can’t prevent droughts but we can manage tree care to minimize the damage drought causes. There is a persistent myth that tree roots penetrate soil deeply enough to find adequate water even in times of drought. Not true! For most trees, the bulk of their roots are in the top 8”-18” (20-45 cm) of soil, making them highly susceptible to changes in soil moisture. Consequently, most preventative measures are best focused in and around the root zone.
Steps you can take to minimize drought damage include:
Watering During droughts, water for personal use takes precedence over outdoor use, resulting in restrictions on outdoor watering. With less water to go around, it can be challenging to ensure that trees receive an adequate share under such conditions. Here are some steps to consider:
- When you can water, water deeply. Slowly soak the root zone (moisten to a depth
of 6-8 inches) within the drip line to promote percolation and minimize
runoff. Do not rely on turf rotors or
sprinklers to water deeply enough.
- Consider the use of slow-release
watering bags or watering trucks for trees in isolated locations. Temporary bubblers or soaker hoses are useful
if a water source is nearby.
- Install irrigation bubblers: Tree
bubblers are inexpensive and will distribute water exactly where it’s needed in
the root zone. New “root watering
systems” (a basket-weave canister with its own bubbler) offer an even more
efficient option for getting water directly to the roots.
- Establish watering priorities:
High – recently planted trees,
Medium – established trees,
Low – lawns and shrubs. While your lawn is easily replaced, mature trees take decades to replace. - Regulate irrigation system pressure to
less than 100 psi (7.03 kilograms per square centimeter) to avoid spray pattern
distortion.
- Confirm that irrigation controllers are
set to operate within applicable watering restrictions. Generally, irrigate sometime during the
overnight hours between 7pm and 7am to minimize evaporation.Consider alternative water sources. Many municipalities offer reclaimed water for landscape use. If available, confirm that sodium levels are acceptable (<200 ppm) before use. Excessive sodium is toxic to trees and will burn foliage and kill trees. Wells may also be an option but, once again, test the water to confirm its suitability for use. Surface ponds are useful for retaining reclaimed water, well water, or surface water pumped from rivers and lakes until used for irrigation. Tanks for rainwater harvesting may reduce evaporation but are an expensive storage option compared to ponds.
Maintenance
Quality tree maintenance is an important on-going process that starts before a drought occurs and continues well after they end. A maintenance program that includes regular monitoring, deep watering, mulching, pruning, and fertilization helps to maintain a tree’s healthy vigor and prepare it for drought.
Quality tree maintenance is an important on-going process that starts before a drought occurs and continues well after they end. A maintenance program that includes regular monitoring, deep watering, mulching, pruning, and fertilization helps to maintain a tree’s healthy vigor and prepare it for drought.
- Prepare a
tree care program and schedule maintenance to occur at regular intervals.
- Monitor
weather and respond promptly to drought conditions.
Mulch
Organic mulch placed in the root zone provides numerous benefits for trees during droughts. Mulch retains soil moisture in the root zone, keeps roots cool, and controls weeds that compete for water. As mulches decompose, they also add nutrients to the soil and improve its structure.
Organic mulch placed in the root zone provides numerous benefits for trees during droughts. Mulch retains soil moisture in the root zone, keeps roots cool, and controls weeds that compete for water. As mulches decompose, they also add nutrients to the soil and improve its structure.
- Place mulch beyond the edge of the
planting hole and create a watering saucer for newly planted trees.
- Maintain a 3”
– 4” (7.5 – 10 cm) layer of organic
mulch within the drip line of existing trees and replenish as often as
necessary to maintain this proper depth. (Keep the mulch 3” – 4” [7.5 – 10 cm] away
from the base of the trunk to avoid tree health concerns.)
Pruning
During persistent droughts, there will be unavoidable dieback in some trees and pruning is going to be necessary. Remember however, that removing live branches and foliage cause trees to expend energy at pruning cuts and the resulting loss of foliage reduces a tree’s ability to respond when growing conditions return to normal.
During persistent droughts, there will be unavoidable dieback in some trees and pruning is going to be necessary. Remember however, that removing live branches and foliage cause trees to expend energy at pruning cuts and the resulting loss of foliage reduces a tree’s ability to respond when growing conditions return to normal.
- Avoid any unnecessary pruning during
droughts.
- When necessary, prune only to remove
dead, broken, insect-infested, or diseased branches that may weaken the tree.
Fertilizers
Excessive soluble fertilizers in the root zone draw moisture out of the roots, resulting in fertilizer burn if adequate water is not provided. Fertilizers also encourage top growth and increase a tree’s need for water at a time when little is available.
Excessive soluble fertilizers in the root zone draw moisture out of the roots, resulting in fertilizer burn if adequate water is not provided. Fertilizers also encourage top growth and increase a tree’s need for water at a time when little is available.
- Avoid applying fertilizers during droughts.
- If fertilizer is necessary, use slow-release fertilizers, applied only at the recommended rates.
Herbicides and Pesticides
Herbicides used in the lawn under a tree's dripline migrate down to tree roots and can be harmful and sometimes fatal to drought-stressed trees.
Herbicides used in the lawn under a tree's dripline migrate down to tree roots and can be harmful and sometimes fatal to drought-stressed trees.
- Avoid herbicide application during droughts.
- Use pesticides to treat for
infestations only as needed.
Summary
With changing global weather patterns and population growth bringing new urbanization to arid regions of the country, droughts and water restrictions may be something that we’ll just have to contend with from now on. With a good understanding of how trees are affected by drought and how to properly react to such conditions, we can be better prepared to promptly diagnose symptoms and develop effective tree care programs.
Mark Smith is an ISA-Certified Arborist, Landscape Architect, and Principal with RVi Planning + Landscape Architecture
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 .5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, Aerial Lift 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 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.
With changing global weather patterns and population growth bringing new urbanization to arid regions of the country, droughts and water restrictions may be something that we’ll just have to contend with from now on. With a good understanding of how trees are affected by drought and how to properly react to such conditions, we can be better prepared to promptly diagnose symptoms and develop effective tree care programs.
Mark Smith is an ISA-Certified Arborist, Landscape Architect, and Principal with RVi Planning + Landscape Architecture
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 .5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, Aerial Lift 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 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 Number of Trees in the World
Edited by Len Phillips
Scientists recently reported that the planet Earth, is home to 3,040,000,000,000, that is 3.04 trillion trees. This means that there are 422 trees for every one of the 7,203,800,000 people on the globe. The scientists used the definition of a tree to be counted as a woody plant, that at breast height has a stem that is at least 4 inches (10 cm) in diameter.
Thomas Crowther from Yale University and colleagues from 15 countries were able to determine this number by merging satellite observations and ground-based tree density measurements. The satellite images gave an overview of where the forests exist while tree density measurements determined how many trees exist in a given area in a given forest. The 429,775 tree density measurements were taken around the world, in ecosystems ranging from deserts to tropical forests. The team created models to capture the relationships between tree density and factors such as climate, topography, and land development.
When compared to the previous worldwide count of 400 billion trees, this study indicated that there are more trees on the planet than previously estimated. Even though the study has dramatically increased the estimate of how many trees there are on the earth's surface, it does not in any way change the current rates of deforestation or the rising impact of global warming.
Edited by Len Phillips
Scientists recently reported that the planet Earth, is home to 3,040,000,000,000, that is 3.04 trillion trees. This means that there are 422 trees for every one of the 7,203,800,000 people on the globe. The scientists used the definition of a tree to be counted as a woody plant, that at breast height has a stem that is at least 4 inches (10 cm) in diameter.
Thomas Crowther from Yale University and colleagues from 15 countries were able to determine this number by merging satellite observations and ground-based tree density measurements. The satellite images gave an overview of where the forests exist while tree density measurements determined how many trees exist in a given area in a given forest. The 429,775 tree density measurements were taken around the world, in ecosystems ranging from deserts to tropical forests. The team created models to capture the relationships between tree density and factors such as climate, topography, and land development.
When compared to the previous worldwide count of 400 billion trees, this study indicated that there are more trees on the planet than previously estimated. Even though the study has dramatically increased the estimate of how many trees there are on the earth's surface, it does not in any way change the current rates of deforestation or the rising impact of global warming.
Forest Comparisons
The study shows the breakdown in the number of trees according to four basic forest types:
The study shows the breakdown in the number of trees according to four basic forest types:
- the tropics and subtropics, on moist
and dry lands contain 1.39 trillion trees,
- the boreal or northern forests just
below the Arctic contain 740 billion trees,
- the temperate broadleaf and coniferous
forests contain 610 billion trees,
- other smaller forests found in deserts,
grasslands, tundra, mangroves, etc. total 300 billion trees.
The Future Forests
The boreal forests have a greater tree density than tropical or temperate forests, probably because of the harsh climate and closer spacing of the short trees. These forests have a potential for a rapid increase in forest cover in response to global warming. If the regions are less cold and forbidding, there will be more carbon dioxide in the air, which trees will use in the photosynthetic process to grow larger and more rapidly. In addition the warmer climate will mean a longer growing season, so the faster growing trees will grow for an even longer period of time.
The boreal forests have a greater tree density than tropical or temperate forests, probably because of the harsh climate and closer spacing of the short trees. These forests have a potential for a rapid increase in forest cover in response to global warming. If the regions are less cold and forbidding, there will be more carbon dioxide in the air, which trees will use in the photosynthetic process to grow larger and more rapidly. In addition the warmer climate will mean a longer growing season, so the faster growing trees will grow for an even longer period of time.
Trees-per-Person Ratios
The study compared the ratio of trees per person in the major countries around the globe. The nation with the single largest number of trees is Russia, with 641 billion trees and 4,461 trees per person based on 2014 population estimates. This large number of trees is because of the vast Siberian boreal forests.
The study compared the ratio of trees per person in the major countries around the globe. The nation with the single largest number of trees is Russia, with 641 billion trees and 4,461 trees per person based on 2014 population estimates. This large number of trees is because of the vast Siberian boreal forests.
- Canada has 318 billion mostly boreal
trees and 8,953 trees per person,
- Brazil has 301 billion tropical trees
and 1,494 trees per person,
- The U.S. has 228 billion mostly
temperate trees and 319 million people in 2014 which equates to 716 trees per
person,
- China has 139 billion boreal and
temperate trees that equate to 102 trees per person,
- India has a tree population of only 35
billion and a population of 1.267 billion, leading to just 28 trees per
person, because of their high density population.
Deforestation
The Crowther study also found that there are 46% fewer trees on the Earth since human civilization began after the last ice age, some 11,000 years ago. For example, Europe use to be almost completely covered by one giant forest and it is now covered mostly by urbanization, fields, or grassland uses.
Human controlled deforestation is making global warming worse. People are harvesting wood or cutting down the forest for other purposes on the land such as agriculture and urbanization. The demand for paper products is at an all time high. This, along with wildfires and pest outbreaks are responsible for the loss of 15.3 billion trees on 45 million acres each year although 5 billion trees may grow back, reseed, or be planted each year. With these losses of trees and only one third of them replaced, scientists predict the globe will be practically treeless within 300 years.
Over half of the losses in the tropics occurred because of traditional deforestation in countries like Brazil and Indonesia. Brazil has slowed its deforestation rate, but in other countries the rates are increasing, including those countries listed below plus Thailand, Laos, and Myanmar. Specific country losses of forest include:
The Crowther study also found that there are 46% fewer trees on the Earth since human civilization began after the last ice age, some 11,000 years ago. For example, Europe use to be almost completely covered by one giant forest and it is now covered mostly by urbanization, fields, or grassland uses.
Human controlled deforestation is making global warming worse. People are harvesting wood or cutting down the forest for other purposes on the land such as agriculture and urbanization. The demand for paper products is at an all time high. This, along with wildfires and pest outbreaks are responsible for the loss of 15.3 billion trees on 45 million acres each year although 5 billion trees may grow back, reseed, or be planted each year. With these losses of trees and only one third of them replaced, scientists predict the globe will be practically treeless within 300 years.
Over half of the losses in the tropics occurred because of traditional deforestation in countries like Brazil and Indonesia. Brazil has slowed its deforestation rate, but in other countries the rates are increasing, including those countries listed below plus Thailand, Laos, and Myanmar. Specific country losses of forest include:
- Cambodia – losing 14.4% per year
- Sierra Leone – losing 12.6% per year
- Madagascar – losing 8.3% per year
- Uruguay – losing 8.1% per year
- Paraguay – losing 7.7% per year
- Liberia – losing 6.9% per year
- Guinea – losing 6.5% per year
- Vietnam – losing 6.4% per year
- Malaysia – losing 6.1% per year
Effect on Global Warming
Trees pull carbon dioxide out of the atmosphere as they grow, and cutting them down and leaving them to rot or be burned releases that carbon back into the atmosphere almost immediately. Each average size tree sequesters about 20 pounds (10 kg) of carbon dioxide per year, which makes planting trees the cheapest and best method of carbon capture and storage.
Using trees for carbon storage is key to keeping the average global temperatures from rising more than 4 Fº (2 Cº) above pre-industrial levels. Scientists believe any temperature increase above that would trigger a climate catastrophe. However, if we were living on an Earth with close to the 6 trillion trees from 10,000 years ago, rather than 3 trillion we have today, the climate change would be much less severe.
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 .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 .5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, Aerial Lift 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 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 pull carbon dioxide out of the atmosphere as they grow, and cutting them down and leaving them to rot or be burned releases that carbon back into the atmosphere almost immediately. Each average size tree sequesters about 20 pounds (10 kg) of carbon dioxide per year, which makes planting trees the cheapest and best method of carbon capture and storage.
Using trees for carbon storage is key to keeping the average global temperatures from rising more than 4 Fº (2 Cº) above pre-industrial levels. Scientists believe any temperature increase above that would trigger a climate catastrophe. However, if we were living on an Earth with close to the 6 trillion trees from 10,000 years ago, rather than 3 trillion we have today, the climate change would be much less severe.
Sources
- Crowther, Thomas, et. al. “Mapping tree
density at a global scale”, Nature, 10.1038, 2015.
- Mooney, Chris, Thomas Crowther,
“Scientists discover that the world contains dramatically more trees than
previously thought”, Nature, 2015.
- Urness, Zach, 'Old-growth trees in the off-trail area of
the Opal Creek Wilderness east of Salem, OR”, Statesman Journal, 2015.
- Valentine, Katie, “Trees Are Disappearing From The World At An
Alarming Rate”, Climate Progress, September 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 .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 .5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, Aerial Lift 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 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 - Street Keeper® honeylocust
By Len Phillips
Street Keeper® honeylocust is a fast-growing and hardy tree for streetscapes and urban landscape settings. Its fern-like foliage adds a unique texture to the landscape while offering a dappled shade underneath its spreading branches. This information has been gathered from the personal observations of the author, living in Massachusetts, Zone 6, and information provided by J. Frank Schmidt & Son nursery.
Botanical Name: Gleditsia triacanthos inermis ‘Draves’
Trade Name: Street Keeper® Honeylocust
Plant Patent: # 21698
Parentage: Discovered near Buffalo, NY by Tom Draves
Family: Fabaceae
Year of Introduction: 2009
Height: 40' – 45'
Spread: 15' – 20'
Form: Narrow, strongly upright, tightly pyramidal
Bloom Period: Spring
Flower: Usually male flowers only, but female flowers on occasion
Fruit: Infrequent long brown seed pods, nearly seedless
Summer Foliage: Dark green, fine textured
Autumn Foliage: Golden yellow in fall
Winter Color: Dark gray bark provides winter interest
Bark: Dark gray to black, thornless
Habitat: Species found in Southeast US from Pennsylvania to Texas and Nebraska
Culture: Moist well drained soil, full sun
Hardiness Zone: 5 – 7 (some reports indicate a tolerance to Zone 2)
Growth Rate: Moderate, 45 feet in 50 years
Pest Problems: Moderate resistance to disease, excellent resistance to pests and easily able to withstand injuries
Storm Resistance: Good except some ice damage susceptibility if not properly pruned
Salt Resistance: Good
Planting: Transplants easily bare root and B&B (somewhat shallow rooted)
Pruning: This tree is more uniform than other Gleditsia cultivars, so it requires little pruning
Propagating: Budded on to species understock
Design Uses: Excellent specimen, good street tree, excellent in lawns and gardens because it casts a very light shadow and has low maintenance needs
Companions: Use with all types of perennials
Awards: Best Tree in 2011 at the Far West Show, Best Plant at the GrootGreenPlus 2012 show in Holland
Other Comments: An ideal tree for parking lots, city streets, parks, and lawns, this cultivar boasts the tight, narrow form that has long been lacking in urban tolerant honeylocust. The ascending branch structure gives Street Keeper® a canopy that is only half as wide as other cultivars.
Fact Sheet: 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 .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 .5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, Aerial Lift 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 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
Street Keeper® honeylocust is a fast-growing and hardy tree for streetscapes and urban landscape settings. Its fern-like foliage adds a unique texture to the landscape while offering a dappled shade underneath its spreading branches. This information has been gathered from the personal observations of the author, living in Massachusetts, Zone 6, and information provided by J. Frank Schmidt & Son nursery.
Botanical Name: Gleditsia triacanthos inermis ‘Draves’
Trade Name: Street Keeper® Honeylocust
Plant Patent: # 21698
Parentage: Discovered near Buffalo, NY by Tom Draves
Family: Fabaceae
Year of Introduction: 2009
Height: 40' – 45'
Spread: 15' – 20'
Form: Narrow, strongly upright, tightly pyramidal
Bloom Period: Spring
Flower: Usually male flowers only, but female flowers on occasion
Fruit: Infrequent long brown seed pods, nearly seedless
Summer Foliage: Dark green, fine textured
Autumn Foliage: Golden yellow in fall
Winter Color: Dark gray bark provides winter interest
Bark: Dark gray to black, thornless
Habitat: Species found in Southeast US from Pennsylvania to Texas and Nebraska
Culture: Moist well drained soil, full sun
Hardiness Zone: 5 – 7 (some reports indicate a tolerance to Zone 2)
Growth Rate: Moderate, 45 feet in 50 years
Pest Problems: Moderate resistance to disease, excellent resistance to pests and easily able to withstand injuries
Storm Resistance: Good except some ice damage susceptibility if not properly pruned
Salt Resistance: Good
Planting: Transplants easily bare root and B&B (somewhat shallow rooted)
Pruning: This tree is more uniform than other Gleditsia cultivars, so it requires little pruning
Propagating: Budded on to species understock
Design Uses: Excellent specimen, good street tree, excellent in lawns and gardens because it casts a very light shadow and has low maintenance needs
Companions: Use with all types of perennials
Awards: Best Tree in 2011 at the Far West Show, Best Plant at the GrootGreenPlus 2012 show in Holland
Other Comments: An ideal tree for parking lots, city streets, parks, and lawns, this cultivar boasts the tight, narrow form that has long been lacking in urban tolerant honeylocust. The ascending branch structure gives Street Keeper® a canopy that is only half as wide as other cultivars.
Fact Sheet: 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 .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 .5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, Aerial Lift 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 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.
Benefits of Trees
Edited by Len Phillips
Most often we plant trees to provide shade and beautify our landscapes. These are great benefits but trees also provide other less obvious benefits. Below are lists of benefits of trees that have been gathered from numerous sources on the Internet. Let me know if you have others.
Benefits to air quality
Edited by Len Phillips
Most often we plant trees to provide shade and beautify our landscapes. These are great benefits but trees also provide other less obvious benefits. Below are lists of benefits of trees that have been gathered from numerous sources on the Internet. Let me know if you have others.
Benefits to air quality
- Tree
planting remains one of the most cost-effective methods for controlling global
warming and decreasing levels of atmospheric carbon dioxide. A tree's ability to absorb carbon is one of
their most valuable properties to tackle climate change.
- Trees are often referred to as the
“lungs of the planet” because of the oxygen they provide to other living things.
Benefits during storms
- Trees
buffer stormwater, rain, and hail with their leaves, trunk, and branches, and
prevent erosion with their roots.
- Trees
in the right location can act as barriers against tidal waves.
- For
every 5% of tree cover in a community, stormwater run-off is reduced by 2%.
- Research
suggests that the effect of trees on wind speeds can extend up to ten times
beyond their own height.
Benefit from cooling
and heating
- The annual mean air temperature of a
city with 1 million people or more can be 1.8 to 5.4°F (1 to 3°C) warmer than
the surrounding area with trees.
- Trees
provide shade and wind-breaking qualities that benefit everyone.
- Planting trees reduces the “heat island
effect” by creating
shade and reducing ambient temperatures through the transpiration of water.
- One
mature tree in the right location, can produce the same cooling effect as 10
room-sized air conditioners in summer.
This can reduce local energy consumption by as much as 10% – 30%. A mature tree in the right location, can save
20% – 50% of the energy used for heating in winter.
Monetary benefit of
trees
- Realtors believe that mature trees have
a strong or moderate impact on the sale potential of homes listed for under
$150,000; on homes over $250,000, this perception becomes a fact.
- The 60 million street trees in the U.S.
have an average value of $525 per tree.
Human health benefit
- The
positive impact on human health from trees is 10% higher in areas with green
space than those areas without trees.
- Every
10% increase in green space can postpone health complaints and health related
issues such as hypertension and stress-related conditions by up to 5 years.
- Trees
can have a therapeutic effect for individuals suffering from Attention Deficit
and Hyperactivity Disorder (ADHD), improving both their attention levels and
social functioning.
- Trees
have a calming effect on the physical and psychological well being of the local
population. This includes lower blood
pressures and cardiovascular diseases, and respiratory diseases.
- Mothers
living near trees have babies with higher birth weights.
- Students
with regular access to green spaces performed better in tests, enhanced
learning skills, social functioning, an increased learning performance, better
test scores, and higher levels of graduation.
- Several
studies have found that access to nature yields better
cognitive functioning, more self-discipline, and greater mental health
overall.
- Adults
living near trees have more patience, more enthusiasm, better health, higher
productivity, and better job satisfaction.
- Hospital
patients who can see trees out their windows are hospitalized 8% fewer days
than their counterparts with no view of landscaping.
- Trees
have been shown to help reduce incidences of skin cancer and other ailments by
filtering polluted air, reducing smog formation, providing shade from solar
radiation, and creating an attractive, calming setting.
- Frequent
exposure to trees can increase a person's life expectancy by five years.
Human community
benefit
- Mature
trees and green spaces help to reduce crime levels and police calls in urban
areas by as much as 7%.
- Apartment
blocks surrounded by mature trees experienced an incredible 52% fewer reported
crimes than those without any
greenery.
- Trees
and green spaces foster community cohesion by creating a sense of place, a
local identity and a system of landmarks.
- Urban
trees provide a range of environmental benefits for the human populations of
towns and cities.
- Urban
trees can help to reduce noise pollution and urban wind tunnel effects by
creating barriers and baffles.
- Tree
areas can provide space for leisure and community activities, helping residents
to take pride in the attractiveness of their location.
Benefit to wildlife
- Established trees create an ecosystem
that provides habitat, nesting, and food for birds and other animals.
- Tree
planting helps to create new habitats for our native fauna.
- Wildlife
habitats support the incredible variety of living things on the planet and is
known as biodiversity.
Safe driving benefit
- Roadside
planting encourages careful driving and can effect drivers’ perceptions of the
speed at which they are traveling and cause them to slow down.
- Roadside
planting can be used to improve pedestrian safety by creating a barrier between
roads and sidewalks.
- Traveling
through tree lined streets may have a calming effect on drivers that results in
fewer incidences of ‘road rage’.
Property value
benefit
- Trees
and green spaces improve property prices by as much as 15%.
- Every
$1 spent on tree planting could save $7 of expenditure in other areas.
- Healthy
urban trees can help to maintain biodiversity by providing natural habitats for
birds, squirrels and other fauna.
- Trees
are capable of removing and storing harmful pollutants that have become
associated with poor urban air and soil quality. These include: sulfur dioxide,
nitrogen oxides and particulates, carbon monoxide, cadmium, nickel, and
lead.
- Properties
in tree lined streets are consistently valued between 5% and 15% higher than
identical properties on roads without trees.
- Trees
can be a stimulus to economic development, attracting new business and
tourism. Commercial retail areas near
trees are more attractive to shoppers, apartments rent more quickly, tenants
stay longer, and space in a wooded setting is more valuable to sell or
rent. Consumers spend up to 13% more at shops near green
landscapes.
- A minimum of 1,060 cu ft (30 cu meters)
of potential rooting volume soil is required to give most tree species any
viable chance of establishing successfully. (20' x 20' x 32” deep)(6m x 6m x
80cm)
Employment benefit
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 .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 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.
- According
to the U.S. National Forest Service,
recreation visitor spending
in National Forests amounted to nearly $11 billion in 2012. All that economic activity sustains about
190,000 full and part-time jobs.
- The
number of foresters and arborists in private companies, in the U.S., exceeds
100,000 people.
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 .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 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.
New Trees for the City
By Len Phillips
Many new trees are introduced by nurseries every year that have been bred for urban tolerance, so municipal arborists should learn more about them, keep themselves up-to-date, and do some experimenting to check them out. It doesn’t hurt to have a plant list that contains 50% of your tried and true species and 50% new species or cultivars to try out. It may be worthwhile to conduct some trials on your own city streets even if you only plant six new trees. I can personally attest to the fact that I found some great new trees for my city that replaced some of my tried and true. Of course I have also had a few failures that I will not plant again and one of my favorite new trees is now out of production and no longer available because it became invasive in other locations.
This article first appeared in Online Seminars May/June 2007. It included the following 17 trees: Autumn Blaze® Maple, Red November™ Maple, Autumn Flame® Red Maple, Brandywine Red Maple, Sun Valley Red Maple, Crescendo™ Sugar Maple, John Pair Sugar Maple, Autumn Splendor Sugar Maple, Georgia Gem® Ash, Golden Colonnade™ Ginkgo, Presidential Gold™ Ginkgo, Adirondack Crabapple, Purple Prince Crabapple, Yarwood Planetree, Accolade® Elm, Triumph™ Elm, and Musashino Columnar Zelkova.
In 2011, this list was revised and 30 new trees bred for tolerance to urban conditions were described. The list included: Metro Gold Maple, Celebration® Maple, Redpointe™ Red Maple, Autumn Fest® Maple, Belle Tower™ Sugar Maple, Flashfire® Sugar Maple, Northern Flare® Maple, Crimson Sunset® Maple, Emerald Avenue® Hornbeam, Prairie Sentinel® Hackberry, Venus® Dogwood, Northern Acclaim® Honeylocust, Espresso™ Kentucky Coffeetree, Wedding Bells Silverbell, Slender Silhouette Sweetgum, Emerald City® Tuliptree, Royal Raindrops® Crabapple, Red Rage® Tupelo, Eye Stopper™ Cork Tree, Exclamation™ Planetree, Heritage® Oak, Urban Pinnacle® Oak, Beijing Gold® Tree Lilac, Harvest Gold Linden, Jefferson Elm, New Harmony Elm, Emerald Sunshine® Elm, Everclear® Elm, Wireless® Zelkova, and City Sprite® Zelkova.
What follows below is a list of 23 trees that have been introduced in the past 4 years and were selected for their tolerance to heat, drought, and life in the city. The trees listed above were not removed because they are no longer suitable for life in the city. They are simply no longer new introductions but you should keep them on your tree list if they have worked out well for you. I have added links to fact sheets where you may find some great photos of these trees.
Highland Park Maple – Acer grandidentatum x A.saccharum 'hipzam' – Zone: 4 - 8; Height: 35’; Spread: 22’; Shape: Pyramidal; Foliage: Dark green; Fall Color: Red.
Intermediate in size, the branches on Highland Park maple create a tightly upright and pyramidal form. It has thick leaves that are tatter resistant and turn bright red in autumn. Faster growing and more upright than the typical bigtooth maple parent, Highland Park is smaller and more heat resistant than the sugar maple parent. Fact Sheet
Armstrong Gold Maple – Acer rubrum 'JFS-KW78' Zone: 4 - 8; Height: 40’; Spread: 12’; Shape: Narrow, tightly fastigiate; Foliage: Medium green; Fall Color: Golden to orange.
Selected from an evaluation of hundreds of seedlings of ‘Armstrong’ maple, this cultivar improves greatly on the parent. It has brighter foliage color, greater foliage density and a compact, less leggy growth habit. This J. Frank Schmidt & Son introduction has an improved columnar form that makes it very desirable for narrow street planting sites. Fact Sheet
Sugar Cone Maple – Acer saccharum 'Sugar Cone' – Zone: 4 - 8; Height: 25'; Spread: 13'; Shape: Compact dwarf pyramid; Foliage: Dark Green; Fall Color: Orange-red.
Dense, compact, and pyramidal, this perfectly named maple is a dwarf sugar maple that looks like an upside down ice cream cone. It stays small and tight and will not outgrow its planting location. It is ideal for planting under overhead utility lines. Fact Sheet
Urban Sunset Maple – Acer truncatum x platanoides 'JFS-KW187' – Zone: 4b - 8; Height: 35’; Spread: 20’; Shape: Narrow pyramidal to upright oval; Foliage: Dark green, glossy; Fall Color: Deep red.
Compact, upright, and narrow, Urban Sunset grows well and develops a naturally uniform canopy with minimal pruning. Easy to grow and relatively problem free, this new introduction produces few seeds and develops into an ideal street tree. Fact Sheet
Renaissance Oasis Birch – Betula papyrifera 'Oenci' – Zone: 3 - 7; Height: 50’; Spread: 30’; Shape: Broadly pyramidal to oval; Foliage: Dark green; Fall Color: Yellow; Insect Resistance: Resistant to bronze birch borer.
Improved drought and pH tolerance are attributes of Renaissance Oasis that originated from the longtime breeding program of Wisconsin nurseryman Tom Pinney, Jr. The mahogany-accented exfoliating bark reveals very attractive bright white bark at an earlier age than is typical of the species. Fact Sheet
Merlot Redbud – Cercis canadensis 'Merlot' – Zone: 6 - 9; Height: 18’; Spread: 20’; Shape: Upright spreading, rounded; Foliage: Glossy, deep purple becoming bronze purple in summer; Fall Color: Yellow; Flower: Magenta rose.
Merlot redbud has a compact form and glossier, more heat resistant leaves than those of Forest Pansy which suggests it will have better performance in warm climates. This tree was selected from the second generation of a cross of ‘Texas White’ x ‘Forest Pansy’ redbuds by Dennis Werner of North Carolina State University. Fact Sheet
The Rising Sun Redbud – Cercis canadensis 'JN2' – PP #21451 – Zone: 5 - 9; Height: 16' | Spread: 20'; Shape: Spreading, rounded; Foliage: Yellow, with orange new growth; Fall Color: Yellow; Flower: Magenta rose.
Rising Sun's springtime show of magenta flowers clustered along bare branches gives way to apricot orange new leaves and yellow summer foliage. This tree also has drought and heat resistance that prevents the leaves from burning in the hot summer sun. Smooth, tan bark adds winter interest. Fact Sheet
Golden Glory Cornelian Cherry – Cornus mas 'Golden Glory' – Zone: 4 - 9; Height: 22’; Spread: 18’; Shape: Broadly oval; Foliage: Glossy, dark green; Fall Color: lavender to reddish purple; Flower: Small, bright yellow flowers cover over the whole tree in early spring; Fruit: Golden yellow, glossy, oblong, 5⁄8" in diameter.
Golden Glory has a more upright growth habit, a glossier leaf surface, and brighter yellow flowers than the species. This improved cultivar makes a more uniform and better looking specimen. Fact Sheet
Emerald Pointe Hardy Rubber Tree – Eucommia ulmoides 'Empozam' – Zone: 5 - 8; Height: 40'; Spread: 15'; Shape: Upright narrow oval; Foliage: Dark green, textured leaf surface; Fall Color: Yellow; Fruit: Seedless.
Emerald Pointe was selected for its upright, ascending branches that form a columnar to narrow oval canopy. The leaves are smaller, darker green, and more heavily textured than the species. Emerald Pointe makes an excellent, narrow street tree of unique appearance. Fact Sheet
Mancana Ash – Fraxinus mandshurica 'Mancana' – Zone: 2 – 8, tolerates -40° F; Height: 40’ - 50'; Spread: 25’ - 30'; Shape: Oval to round, strong central leader with upward-arching branches; Foliage: Attractive compound leaves, chartreuse to medium green; Fall Color: Bright yellow, leaves all drop in unison; Flower: Insignificant with a low production of seed; Fruit: Considered seedless.
Mancana ash has a color of yellow bark on new wood that provides winter interest and contrasts with the gray brown lenticels and narrow ridges of the tree's older bark. This tree does well in a wide range of soil types and moisture levels and has excellent resistance to urban pollution. Most importantly, this tree is highly resistant to Emerald Ash Borer and has no other pest problems, plus it is disliked by deer. Mancana does especially well in winter with heavy snow and most ice storms. Fact Sheet
Coral Sun Goldenrain Tree – Koelreuteria paniculata 'Coral Sun' – Zone: 6 - 9; Height: 20'; Spread: 20'; Shape: Rounded; Foliage: Emerges coral pink, maturing to medium green; Fall Color: Golden yellow; Flower: Yellow.
Fern-like compound leaflets on Coral Sun Goldenrain Tree emerge bright coral and gradually mature to medium green. Their striking contrast against bright coral pink stems delivers a new color combination to a tried and true, street-tough urban tree. This cultivar is suitable for growing under overhead utility lines. Fact Sheet
Summerburst Goldenrain Tree – Koelreuteria paniculata 'JFS-Sunleaf' – Zone: 5 - 9; Height: 30'; Spread: 30'; Shape: Rounded; Foliage: Pinnately compound, glossy dark green; Fall Color: Yellow; Flower: Bright yellow, in large clusters.
Summerburst Goldenrain Tree has lantern-like seed capsules that are blushed with pink and last for most of the late summer and early autumn. Summerburst has foliage that holds up nicely in summer heat. Its leaves are darker green, smoother and more glossy than typical of the species. Fact Sheet
Afterburner Tupelo – Nyssa sylvatica 'David Odom' – Zone: 5 - 9; Height: 35’; Spread: 20’; Shape: Upright pyramidal to oval; Foliage: Bright green, glossy; Fall Color: Bright red; Fruit: Blue-black, 3⁄8" in diameter.
The symmetrical, uniform and upright branch structure, and straight central leader make Afterburner Tupelo easier to grow and better suited than seedlings of the species for use as a street tree. High gloss foliage shines through the summer and then turns bright red in fall, burning brightly after most native tupelo have defoliated. Fact Sheet
Western Sun Pistache – Pistacia chinensis 'Pair's Choice' – Zone: 6 - 9; Height: 30’; Spread: 30’; Shape: Upright spreading to rounded; Foliage: Dark green, pinnately compound; Fall Color: Orange to red; Fruit: None.
Western Sun Pistache has a robust growth habit that produces a sturdy trunk with stout, ascending branches to provide good clearance for pedestrians and street traffic. This male selection is seedless and has a bold appearance and bright fall color. Fact Sheet
Tower Poplar – Populus x canescens – Zone: 2b - 9; Height: 50'; Spread: 14'; Shape: Narrowly columnar;
Foliage: Medium green; Fall Color: Yellow.
Fast growing, drought tolerant, and very cold hardy, Tower Poplar's tightly columnar hybrid has improved disease and insect resistance. Excellent for windbreaks and screens, it is urban tolerant, and a good replacement for Lombardy Poplar. Fact Sheet
Javelin Pear – Pyrus 'NCPX1' – Zone: 5 - 10; Height: 35’; Spread: 10’; Shape: Fastigiate, tightly columnar;
Foliage: Purple to bronze green; Fall Color: Purple to maroon; Flower: Pink buds open to white flowers.
The tightest and most columnar pear known at this time, Javelin stays narrow as it matures. This tree's unique foliage leafs out purple and matures to bronze green in the heat of summer. Javelin was developed at North Carolina State University and is a fireblight resistant pear. Designers say that Javelin creates a landscape exclamation point and is also excellent for use on narrow streets. Fact Sheet
Beacon Oak – Quercus bicolor 'Bonnie and Mike' – Zone: 4 - 8; Height: 40'; Spread: 15'; Shape: Narrowly columnar; Foliage: Green; Fall Color: Yellow.
Tightly columnar and urban adaptable, Beacon oak was discovered by famed plantsman Dr. Michael Dirr. The stout upright branching structure and dense green foliage make this an ideal street tree that provides a strong visual statement. Beacon also has nice autumn color. Fact Sheet
Cobblestone Oak – Quercus macrocarpa 'JFS-KW14' – Zone: 3 - 8; Height: 55’; Spread: 45’; Shape: Broadly oval; Foliage: Dark green; Fall Color: Yellow.
Cobblestone oak has a traditional form of bur oak with very corky bark and unusually corky branches. It has an “ancient tree” look at a young age. Cobblestone's handsome foliage is dark green and the tree was selected for mildew and anthracnose resistance. Fact Sheet
Streetspire Oak – Quercus robur x alba 'JFS-KW1QX' – Zone: 4 - 8; Height: 45'; Spread: 14'; Shape: Narrow, columnar; Foliage: Dark green; Fall Color: Rusty red.
The dark green leaves of the narrowly columnar Streetspire oak are mildew resistant. Turning red in autumn, the leaves fall to reveal stiffly upright branches. While similar to Crimson Spire™ oak, Streetspire does not hold any brown foliage through the winter. Its wide crotch angles and short upsweeping branches create a storm resistant structure. Fact Sheet
Skinny Genes Oak – Quercus robur x alba 'JFS-KW2QX' – Zone: 4 - 8; Height: 45’; Spread: 10’; Shape: Columnar, tightly fastigiate; Foliage: Dark green, glossy; Fall Color: Yellow to tawny yellow.
Skinny Genes oak has a columnar and fastigiate form. This hybrid of English x White Oak is extremely narrow. The glossy, very dark green foliage is mildew resistant and clean through the summer months before turning yellow in autumn. A living exclamation point, Skinny Genes was selected from second-generation seedlings of Crimson Spire™. Fact Sheet
Forest Knight Oak – Quercus robur x alba 'Tabor' – PP #21382 – Zone: 4 - 8; Height: 50'; Spread: 40'; Shape: Broadly oval; Foliage: Dark green, glossy; Fall Color: Orange-red.
Sturdy, symmetrical, and broadly oval, Forest Knight develops into an excellent street tree. It has good form and strong branching that combined with mildew resistant foliage and orange-red fall color, make this tree an excellent choice for street tree plantings. Fact Sheet
Kindred Spirit Oak – Quercus robur x bicolor 'Nadler' – Zone: 4 - 8; Height: 30’; Spread: 6’; Shape: Tightly columnar; Foliage: Medium green; Fall Color: Yellow to yellow-brown.
Among the narrowest and tightest of columnar trees, Kindred Spirit's growth habit, mildew and drought resistance, and tolerance of urban soils make this hybrid of English and swamp white oak ideal for narrow city streets. The foliage is moderately glossy. Fact Sheet
Prairie Expedition Elm – Ulmus americana 'Lewis & Clark' – Zone: 2b - 9; Height: 55'; Spread: 60'; Shape: Broad, rounded to spreading vase; Foliage: Dark green; Fall Color: Yellow; Disease Tolerance: Dutch Elm Disease resistant.
Extremely cold hardy, the Prairie Expedition Elm is a tough American elm native that descends from a lone survivor of Dutch Elm Disease found near Fargo, ND. Fast growth of the broadly spreading, vase shaped canopy delivers quick shade in cold prairies and harsh urban environments. Fact Sheet
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 .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 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
Many new trees are introduced by nurseries every year that have been bred for urban tolerance, so municipal arborists should learn more about them, keep themselves up-to-date, and do some experimenting to check them out. It doesn’t hurt to have a plant list that contains 50% of your tried and true species and 50% new species or cultivars to try out. It may be worthwhile to conduct some trials on your own city streets even if you only plant six new trees. I can personally attest to the fact that I found some great new trees for my city that replaced some of my tried and true. Of course I have also had a few failures that I will not plant again and one of my favorite new trees is now out of production and no longer available because it became invasive in other locations.
This article first appeared in Online Seminars May/June 2007. It included the following 17 trees: Autumn Blaze® Maple, Red November™ Maple, Autumn Flame® Red Maple, Brandywine Red Maple, Sun Valley Red Maple, Crescendo™ Sugar Maple, John Pair Sugar Maple, Autumn Splendor Sugar Maple, Georgia Gem® Ash, Golden Colonnade™ Ginkgo, Presidential Gold™ Ginkgo, Adirondack Crabapple, Purple Prince Crabapple, Yarwood Planetree, Accolade® Elm, Triumph™ Elm, and Musashino Columnar Zelkova.
In 2011, this list was revised and 30 new trees bred for tolerance to urban conditions were described. The list included: Metro Gold Maple, Celebration® Maple, Redpointe™ Red Maple, Autumn Fest® Maple, Belle Tower™ Sugar Maple, Flashfire® Sugar Maple, Northern Flare® Maple, Crimson Sunset® Maple, Emerald Avenue® Hornbeam, Prairie Sentinel® Hackberry, Venus® Dogwood, Northern Acclaim® Honeylocust, Espresso™ Kentucky Coffeetree, Wedding Bells Silverbell, Slender Silhouette Sweetgum, Emerald City® Tuliptree, Royal Raindrops® Crabapple, Red Rage® Tupelo, Eye Stopper™ Cork Tree, Exclamation™ Planetree, Heritage® Oak, Urban Pinnacle® Oak, Beijing Gold® Tree Lilac, Harvest Gold Linden, Jefferson Elm, New Harmony Elm, Emerald Sunshine® Elm, Everclear® Elm, Wireless® Zelkova, and City Sprite® Zelkova.
What follows below is a list of 23 trees that have been introduced in the past 4 years and were selected for their tolerance to heat, drought, and life in the city. The trees listed above were not removed because they are no longer suitable for life in the city. They are simply no longer new introductions but you should keep them on your tree list if they have worked out well for you. I have added links to fact sheets where you may find some great photos of these trees.
Highland Park Maple – Acer grandidentatum x A.saccharum 'hipzam' – Zone: 4 - 8; Height: 35’; Spread: 22’; Shape: Pyramidal; Foliage: Dark green; Fall Color: Red.
Intermediate in size, the branches on Highland Park maple create a tightly upright and pyramidal form. It has thick leaves that are tatter resistant and turn bright red in autumn. Faster growing and more upright than the typical bigtooth maple parent, Highland Park is smaller and more heat resistant than the sugar maple parent. Fact Sheet
Armstrong Gold Maple – Acer rubrum 'JFS-KW78' Zone: 4 - 8; Height: 40’; Spread: 12’; Shape: Narrow, tightly fastigiate; Foliage: Medium green; Fall Color: Golden to orange.
Selected from an evaluation of hundreds of seedlings of ‘Armstrong’ maple, this cultivar improves greatly on the parent. It has brighter foliage color, greater foliage density and a compact, less leggy growth habit. This J. Frank Schmidt & Son introduction has an improved columnar form that makes it very desirable for narrow street planting sites. Fact Sheet
Sugar Cone Maple – Acer saccharum 'Sugar Cone' – Zone: 4 - 8; Height: 25'; Spread: 13'; Shape: Compact dwarf pyramid; Foliage: Dark Green; Fall Color: Orange-red.
Dense, compact, and pyramidal, this perfectly named maple is a dwarf sugar maple that looks like an upside down ice cream cone. It stays small and tight and will not outgrow its planting location. It is ideal for planting under overhead utility lines. Fact Sheet
Urban Sunset Maple – Acer truncatum x platanoides 'JFS-KW187' – Zone: 4b - 8; Height: 35’; Spread: 20’; Shape: Narrow pyramidal to upright oval; Foliage: Dark green, glossy; Fall Color: Deep red.
Compact, upright, and narrow, Urban Sunset grows well and develops a naturally uniform canopy with minimal pruning. Easy to grow and relatively problem free, this new introduction produces few seeds and develops into an ideal street tree. Fact Sheet
Renaissance Oasis Birch – Betula papyrifera 'Oenci' – Zone: 3 - 7; Height: 50’; Spread: 30’; Shape: Broadly pyramidal to oval; Foliage: Dark green; Fall Color: Yellow; Insect Resistance: Resistant to bronze birch borer.
Improved drought and pH tolerance are attributes of Renaissance Oasis that originated from the longtime breeding program of Wisconsin nurseryman Tom Pinney, Jr. The mahogany-accented exfoliating bark reveals very attractive bright white bark at an earlier age than is typical of the species. Fact Sheet
Merlot Redbud – Cercis canadensis 'Merlot' – Zone: 6 - 9; Height: 18’; Spread: 20’; Shape: Upright spreading, rounded; Foliage: Glossy, deep purple becoming bronze purple in summer; Fall Color: Yellow; Flower: Magenta rose.
Merlot redbud has a compact form and glossier, more heat resistant leaves than those of Forest Pansy which suggests it will have better performance in warm climates. This tree was selected from the second generation of a cross of ‘Texas White’ x ‘Forest Pansy’ redbuds by Dennis Werner of North Carolina State University. Fact Sheet
The Rising Sun Redbud – Cercis canadensis 'JN2' – PP #21451 – Zone: 5 - 9; Height: 16' | Spread: 20'; Shape: Spreading, rounded; Foliage: Yellow, with orange new growth; Fall Color: Yellow; Flower: Magenta rose.
Rising Sun's springtime show of magenta flowers clustered along bare branches gives way to apricot orange new leaves and yellow summer foliage. This tree also has drought and heat resistance that prevents the leaves from burning in the hot summer sun. Smooth, tan bark adds winter interest. Fact Sheet
Golden Glory Cornelian Cherry – Cornus mas 'Golden Glory' – Zone: 4 - 9; Height: 22’; Spread: 18’; Shape: Broadly oval; Foliage: Glossy, dark green; Fall Color: lavender to reddish purple; Flower: Small, bright yellow flowers cover over the whole tree in early spring; Fruit: Golden yellow, glossy, oblong, 5⁄8" in diameter.
Golden Glory has a more upright growth habit, a glossier leaf surface, and brighter yellow flowers than the species. This improved cultivar makes a more uniform and better looking specimen. Fact Sheet
Emerald Pointe Hardy Rubber Tree – Eucommia ulmoides 'Empozam' – Zone: 5 - 8; Height: 40'; Spread: 15'; Shape: Upright narrow oval; Foliage: Dark green, textured leaf surface; Fall Color: Yellow; Fruit: Seedless.
Emerald Pointe was selected for its upright, ascending branches that form a columnar to narrow oval canopy. The leaves are smaller, darker green, and more heavily textured than the species. Emerald Pointe makes an excellent, narrow street tree of unique appearance. Fact Sheet
Mancana Ash – Fraxinus mandshurica 'Mancana' – Zone: 2 – 8, tolerates -40° F; Height: 40’ - 50'; Spread: 25’ - 30'; Shape: Oval to round, strong central leader with upward-arching branches; Foliage: Attractive compound leaves, chartreuse to medium green; Fall Color: Bright yellow, leaves all drop in unison; Flower: Insignificant with a low production of seed; Fruit: Considered seedless.
Mancana ash has a color of yellow bark on new wood that provides winter interest and contrasts with the gray brown lenticels and narrow ridges of the tree's older bark. This tree does well in a wide range of soil types and moisture levels and has excellent resistance to urban pollution. Most importantly, this tree is highly resistant to Emerald Ash Borer and has no other pest problems, plus it is disliked by deer. Mancana does especially well in winter with heavy snow and most ice storms. Fact Sheet
Coral Sun Goldenrain Tree – Koelreuteria paniculata 'Coral Sun' – Zone: 6 - 9; Height: 20'; Spread: 20'; Shape: Rounded; Foliage: Emerges coral pink, maturing to medium green; Fall Color: Golden yellow; Flower: Yellow.
Fern-like compound leaflets on Coral Sun Goldenrain Tree emerge bright coral and gradually mature to medium green. Their striking contrast against bright coral pink stems delivers a new color combination to a tried and true, street-tough urban tree. This cultivar is suitable for growing under overhead utility lines. Fact Sheet
Summerburst Goldenrain Tree – Koelreuteria paniculata 'JFS-Sunleaf' – Zone: 5 - 9; Height: 30'; Spread: 30'; Shape: Rounded; Foliage: Pinnately compound, glossy dark green; Fall Color: Yellow; Flower: Bright yellow, in large clusters.
Summerburst Goldenrain Tree has lantern-like seed capsules that are blushed with pink and last for most of the late summer and early autumn. Summerburst has foliage that holds up nicely in summer heat. Its leaves are darker green, smoother and more glossy than typical of the species. Fact Sheet
Afterburner Tupelo – Nyssa sylvatica 'David Odom' – Zone: 5 - 9; Height: 35’; Spread: 20’; Shape: Upright pyramidal to oval; Foliage: Bright green, glossy; Fall Color: Bright red; Fruit: Blue-black, 3⁄8" in diameter.
The symmetrical, uniform and upright branch structure, and straight central leader make Afterburner Tupelo easier to grow and better suited than seedlings of the species for use as a street tree. High gloss foliage shines through the summer and then turns bright red in fall, burning brightly after most native tupelo have defoliated. Fact Sheet
Western Sun Pistache – Pistacia chinensis 'Pair's Choice' – Zone: 6 - 9; Height: 30’; Spread: 30’; Shape: Upright spreading to rounded; Foliage: Dark green, pinnately compound; Fall Color: Orange to red; Fruit: None.
Western Sun Pistache has a robust growth habit that produces a sturdy trunk with stout, ascending branches to provide good clearance for pedestrians and street traffic. This male selection is seedless and has a bold appearance and bright fall color. Fact Sheet
Tower Poplar – Populus x canescens – Zone: 2b - 9; Height: 50'; Spread: 14'; Shape: Narrowly columnar;
Foliage: Medium green; Fall Color: Yellow.
Fast growing, drought tolerant, and very cold hardy, Tower Poplar's tightly columnar hybrid has improved disease and insect resistance. Excellent for windbreaks and screens, it is urban tolerant, and a good replacement for Lombardy Poplar. Fact Sheet
Javelin Pear – Pyrus 'NCPX1' – Zone: 5 - 10; Height: 35’; Spread: 10’; Shape: Fastigiate, tightly columnar;
Foliage: Purple to bronze green; Fall Color: Purple to maroon; Flower: Pink buds open to white flowers.
The tightest and most columnar pear known at this time, Javelin stays narrow as it matures. This tree's unique foliage leafs out purple and matures to bronze green in the heat of summer. Javelin was developed at North Carolina State University and is a fireblight resistant pear. Designers say that Javelin creates a landscape exclamation point and is also excellent for use on narrow streets. Fact Sheet
Beacon Oak – Quercus bicolor 'Bonnie and Mike' – Zone: 4 - 8; Height: 40'; Spread: 15'; Shape: Narrowly columnar; Foliage: Green; Fall Color: Yellow.
Tightly columnar and urban adaptable, Beacon oak was discovered by famed plantsman Dr. Michael Dirr. The stout upright branching structure and dense green foliage make this an ideal street tree that provides a strong visual statement. Beacon also has nice autumn color. Fact Sheet
Cobblestone Oak – Quercus macrocarpa 'JFS-KW14' – Zone: 3 - 8; Height: 55’; Spread: 45’; Shape: Broadly oval; Foliage: Dark green; Fall Color: Yellow.
Cobblestone oak has a traditional form of bur oak with very corky bark and unusually corky branches. It has an “ancient tree” look at a young age. Cobblestone's handsome foliage is dark green and the tree was selected for mildew and anthracnose resistance. Fact Sheet
Streetspire Oak – Quercus robur x alba 'JFS-KW1QX' – Zone: 4 - 8; Height: 45'; Spread: 14'; Shape: Narrow, columnar; Foliage: Dark green; Fall Color: Rusty red.
The dark green leaves of the narrowly columnar Streetspire oak are mildew resistant. Turning red in autumn, the leaves fall to reveal stiffly upright branches. While similar to Crimson Spire™ oak, Streetspire does not hold any brown foliage through the winter. Its wide crotch angles and short upsweeping branches create a storm resistant structure. Fact Sheet
Skinny Genes Oak – Quercus robur x alba 'JFS-KW2QX' – Zone: 4 - 8; Height: 45’; Spread: 10’; Shape: Columnar, tightly fastigiate; Foliage: Dark green, glossy; Fall Color: Yellow to tawny yellow.
Skinny Genes oak has a columnar and fastigiate form. This hybrid of English x White Oak is extremely narrow. The glossy, very dark green foliage is mildew resistant and clean through the summer months before turning yellow in autumn. A living exclamation point, Skinny Genes was selected from second-generation seedlings of Crimson Spire™. Fact Sheet
Forest Knight Oak – Quercus robur x alba 'Tabor' – PP #21382 – Zone: 4 - 8; Height: 50'; Spread: 40'; Shape: Broadly oval; Foliage: Dark green, glossy; Fall Color: Orange-red.
Sturdy, symmetrical, and broadly oval, Forest Knight develops into an excellent street tree. It has good form and strong branching that combined with mildew resistant foliage and orange-red fall color, make this tree an excellent choice for street tree plantings. Fact Sheet
Kindred Spirit Oak – Quercus robur x bicolor 'Nadler' – Zone: 4 - 8; Height: 30’; Spread: 6’; Shape: Tightly columnar; Foliage: Medium green; Fall Color: Yellow to yellow-brown.
Among the narrowest and tightest of columnar trees, Kindred Spirit's growth habit, mildew and drought resistance, and tolerance of urban soils make this hybrid of English and swamp white oak ideal for narrow city streets. The foliage is moderately glossy. Fact Sheet
Prairie Expedition Elm – Ulmus americana 'Lewis & Clark' – Zone: 2b - 9; Height: 55'; Spread: 60'; Shape: Broad, rounded to spreading vase; Foliage: Dark green; Fall Color: Yellow; Disease Tolerance: Dutch Elm Disease resistant.
Extremely cold hardy, the Prairie Expedition Elm is a tough American elm native that descends from a lone survivor of Dutch Elm Disease found near Fargo, ND. Fast growth of the broadly spreading, vase shaped canopy delivers quick shade in cold prairies and harsh urban environments. Fact Sheet
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 .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 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.
Dealing with Anthracnose
Edited by Len Phillips
Anthracnose is a term applied to a group of foliage diseases that affect most hardwood tree species throughout the United States. Anthracnose diseases result in leaf spots, defoliation, blights, cankers, or dieback depending on the trees or shrubs infected.
Spring Symptoms
Anthracnose is most prevalent and destructive in early spring when cool, moist weather conditions favor disease development. The disease is most common when new shoot and leaf growth are combined with temperatures ranging from 50-68°F (10-20°C) and spring rain. Anthracnose can also reoccur in the summer when cool, wet weather is paired with tender leaf growth. Blight and defoliation usually occur when leaves are small and succulent.
Leaf spotting and defoliation have very little effect on the health of the tree. However, several consecutive years of defoliation will severely weaken trees, making them susceptible to invasion by opportunistic pests like boring insects and secondary disease causing organisms such as canker and root decay fungi resulting in more significant damage.
Spreading Spores
Anthracnose is caused by several genera of closely related fungi. The pathogens overwinter in twigs, buds, fruit, fallen leaves, or petioles, depending on which hosts and pathogens are involved. The disease cycle begins in spring, coinciding with bud-break, when spores produced by anthracnose fungi are dispersed to newly forming leaves, short distances by splashing water or spread long distances by wind. Under cool, moist conditions, spores germinate and infect susceptible plant tissue and begin their destructive activity. Shortly after lesions develop, “summer spores” are produced on the diseased plant tissue. These summer spores are spread to healthy tissue where they cause new infections. As long as moist weather conditions prevail, summer spores are produced from lesions on diseased plant parts. These spores are responsible for infections that occur in late spring and summer.
Exception Species
On some tree species, the anthracnose fungi invade twigs from infected leaves. The pathogen may continue to grow in the twigs during the autumn after the leaves are cast, and in the spring prior to bud-break. Subsequently, infected twigs and buds may be killed during the dormant season.
Crowns of severely diseased trees appear thin and scrubby. Often, the foliage is tufted on ends of branches, while the center of the tree is defoliated. Trees defoliated by anthracnose usually produce a second set of leaves in late spring or summer.
Hosts
Foliar symptoms of anthracnose vary considerably among host species. Below is a list of trees and the anthracnose species that attack each tree.
Tree Fungal Pathogen
Ash (Fraxinus) Discula, Fraxinea
Birch (Betula) Cryptocline betularum, Discula betulina
Black Walnut, Butternut (Juglans) Marssoniella juglandis
Buckeye (Aesculus) Colletotrichum gloeosporioides
Elm (Ulmus) Stegophora ulmea
Hornbeam (Carpinus) Monostichella robergei
Maple (Acer) Aureobasidium apocryptum, Discula campestris, Discula umbrinella, Colletotrichum gloeosporioides
Oak (Quercus) Discula quercina
For ash, maple, and oak trees, young leaves and shoots are highly susceptible to infection from the anthracnose fungi, but mature fully expanded leaves are largely resistant. Mature leaves of these trees only become infected through minor wounds like damage from insect pests. As a result, once the weather becomes dry and the leaves mature, disease infected growth will end and the tree will replace the lost leaves with a new flush of growth. In contrast, on trees like walnut and hornbeam, anthracnose can continue to progress through the summer months.
On some tree species, including sycamore, white oak, and maple, buds and succulent new shoots may be killed as a result of anthracnose. Cankers may also appear on twigs and small branches resulting in twig distortion and dieback.
Cultural Control
Sanitation practices, which eliminate sources of the overwintering fungi, will provide some degree of control against anthracnose. Diseased leaves should be collected and destroyed in the fall, and diseased twigs and branches should be pruned out and destroyed to whatever degree possible. Consider using soil drenches and trunk sprays with a 50-50 mixture of Agri-fos and water. For trunk sprays only, use Pentrabark, a bark penetrating adjuvant. Usually one treatment, early in the spring, will provide yearlong protection especially on dogwoods.
Periodic pruning will allow optimum light and air penetrations of the crown, which will inhibit disease development by allowing more rapid drying of plant tissue following rains. Periodic fertilization will maintain tree vigor and help offset the deleterious effects of any premature defoliation from anthracnose.
Chemical Control
Properly timed fungicide applications will help control anthracnose. Fungicides are applied at periodic intervals during the spring in order to protect developing plant tissue from infection. Once infection occurs, however, chemical sprays are ineffective in preventing further disease development. The effectiveness of chemical control is dependent on spring weather conditions, the proximity of untreated trees to sprayed trees, and the thoroughness of the sanitation program. Generally, more frequent applications of fungicides are necessary to obtain a high degree of control during cool, moist springs. With Sycamores there is an option to inject fungicide into the tree providing multiple years of protection. Consult the local state for the proper fungicide recommendations, rates, and timings for control of anthracnose on specific tree species.
Sources
Edited by Len Phillips
Anthracnose is a term applied to a group of foliage diseases that affect most hardwood tree species throughout the United States. Anthracnose diseases result in leaf spots, defoliation, blights, cankers, or dieback depending on the trees or shrubs infected.
Spring Symptoms
Anthracnose is most prevalent and destructive in early spring when cool, moist weather conditions favor disease development. The disease is most common when new shoot and leaf growth are combined with temperatures ranging from 50-68°F (10-20°C) and spring rain. Anthracnose can also reoccur in the summer when cool, wet weather is paired with tender leaf growth. Blight and defoliation usually occur when leaves are small and succulent.
Leaf spotting and defoliation have very little effect on the health of the tree. However, several consecutive years of defoliation will severely weaken trees, making them susceptible to invasion by opportunistic pests like boring insects and secondary disease causing organisms such as canker and root decay fungi resulting in more significant damage.
Spreading Spores
Anthracnose is caused by several genera of closely related fungi. The pathogens overwinter in twigs, buds, fruit, fallen leaves, or petioles, depending on which hosts and pathogens are involved. The disease cycle begins in spring, coinciding with bud-break, when spores produced by anthracnose fungi are dispersed to newly forming leaves, short distances by splashing water or spread long distances by wind. Under cool, moist conditions, spores germinate and infect susceptible plant tissue and begin their destructive activity. Shortly after lesions develop, “summer spores” are produced on the diseased plant tissue. These summer spores are spread to healthy tissue where they cause new infections. As long as moist weather conditions prevail, summer spores are produced from lesions on diseased plant parts. These spores are responsible for infections that occur in late spring and summer.
Exception Species
On some tree species, the anthracnose fungi invade twigs from infected leaves. The pathogen may continue to grow in the twigs during the autumn after the leaves are cast, and in the spring prior to bud-break. Subsequently, infected twigs and buds may be killed during the dormant season.
Crowns of severely diseased trees appear thin and scrubby. Often, the foliage is tufted on ends of branches, while the center of the tree is defoliated. Trees defoliated by anthracnose usually produce a second set of leaves in late spring or summer.
Hosts
Foliar symptoms of anthracnose vary considerably among host species. Below is a list of trees and the anthracnose species that attack each tree.
Tree Fungal Pathogen
Ash (Fraxinus) Discula, Fraxinea
Birch (Betula) Cryptocline betularum, Discula betulina
Black Walnut, Butternut (Juglans) Marssoniella juglandis
Buckeye (Aesculus) Colletotrichum gloeosporioides
Elm (Ulmus) Stegophora ulmea
Hornbeam (Carpinus) Monostichella robergei
Maple (Acer) Aureobasidium apocryptum, Discula campestris, Discula umbrinella, Colletotrichum gloeosporioides
Oak (Quercus) Discula quercina
For ash, maple, and oak trees, young leaves and shoots are highly susceptible to infection from the anthracnose fungi, but mature fully expanded leaves are largely resistant. Mature leaves of these trees only become infected through minor wounds like damage from insect pests. As a result, once the weather becomes dry and the leaves mature, disease infected growth will end and the tree will replace the lost leaves with a new flush of growth. In contrast, on trees like walnut and hornbeam, anthracnose can continue to progress through the summer months.
On some tree species, including sycamore, white oak, and maple, buds and succulent new shoots may be killed as a result of anthracnose. Cankers may also appear on twigs and small branches resulting in twig distortion and dieback.
Cultural Control
Sanitation practices, which eliminate sources of the overwintering fungi, will provide some degree of control against anthracnose. Diseased leaves should be collected and destroyed in the fall, and diseased twigs and branches should be pruned out and destroyed to whatever degree possible. Consider using soil drenches and trunk sprays with a 50-50 mixture of Agri-fos and water. For trunk sprays only, use Pentrabark, a bark penetrating adjuvant. Usually one treatment, early in the spring, will provide yearlong protection especially on dogwoods.
Periodic pruning will allow optimum light and air penetrations of the crown, which will inhibit disease development by allowing more rapid drying of plant tissue following rains. Periodic fertilization will maintain tree vigor and help offset the deleterious effects of any premature defoliation from anthracnose.
Chemical Control
Properly timed fungicide applications will help control anthracnose. Fungicides are applied at periodic intervals during the spring in order to protect developing plant tissue from infection. Once infection occurs, however, chemical sprays are ineffective in preventing further disease development. The effectiveness of chemical control is dependent on spring weather conditions, the proximity of untreated trees to sprayed trees, and the thoroughness of the sanitation program. Generally, more frequent applications of fungicides are necessary to obtain a high degree of control during cool, moist springs. With Sycamores there is an option to inject fungicide into the tree providing multiple years of protection. Consult the local state for the proper fungicide recommendations, rates, and timings for control of anthracnose on specific tree species.
Sources
- Fraedrich, Bruce R., “Anthracnose of Shade Trees”, Bartlett Tree
Experts
- Koetter, Rebecca, and Michelle Grabowski,
"Anthracnose", University of Minnesota Extension, 2015.
The mention of product names is for the reader's information only. Do not consider them an indorsement by Online Seminars.
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 .5 CEUs toward Certified Arborist, Utility Specialist, 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 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.
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 .5 CEUs toward Certified Arborist, Utility Specialist, 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 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 of
Flowering Cherry Trees
By Len Phillips
Flowering cherry trees are a long time favorite that does well in the city, once they become established. Most of the species and cultivars transplant with ease. The description that follows provides a summary of similarities that all the species and cultivars possess. The bottom half of this article describes the author's opinion of the best of the flowering cherry cultivars for growing in the city. This information has been gathered from personal observations of the author, living in Massachusetts, Zone 6, and information provided by J. Frank Schmidt & Son.
Bloom Period: Spring
Fruit: Small, color varies with cultivar
Bark: Often smooth and reddish
Hardiness Zone: Varies according to the cultivar
Growth Rate: Medium to fast
Pest Resistance: Seldom infected with foliage diseases or insects
Salt Resistance: Good to excellent
Planting: Easy to transplant bare root and B&B, suitable for planting in CU-Structural Soil
Pruning: Prune for clearance only
Design Uses: Excellent for street trees and trees in small yards, good as a specimen or in groupings
Akebono Cherry – Prunus x yedoensis ‘Akebono’ – Zone: 5-9; Height: 25'; Spread: 25'; Shape: Upright, spreading; Foliage: Medium green; Fall Color: Yellowish; Flower: Delicate pink; Fruit: occasional shiny black fruits.
Clouds of airy pink blossoms crowd the upright spreading branches of Akebono cherry. The blooms have a stronger pink tint than the better-known Yoshino Cherry. Fact Sheet
Amanogawa Cherry – Prunus serrulata ‘Amanogawa’ – Zone: 5-9; Height: 20’; Spread: 6’; Shape: Columnar,
fastigiate branching; Foliage: Green; Fall Color: Bronze; Flower: Pale pink, semi-double.
Very narrow and tightly upright in growth, Amanogawa cherry forms a column of light pink flowers in the spring. Sometimes this tree will produce small black fruits. Fact Sheet
Canada Red Improved Chokecherry – Prunus virginiana ‘Canada Red’ – Zone: 2-6; Height: 25’; Spread: 20’;
Shape: Upright spreading, rounded; Foliage: Leaves emerge green, turn purple in summer; Fall Color: Red to reddish purple; Flower: Small white, in long clusters; Fruits: red, becoming dark purple.
A very cold hardy tree, Canada Red Improved is used for its foliage which changes from green in spring to dark purple as the weather warms, then intensifies to reddish in autumn. Fact Sheet
First Blush™ Cherry – Prunus ‘JFS-KW14’ – Zone: 5-9; Height: 25'; Spread: 12'; Shape: Upright narrow oval;
Foliage: Dark green; Fall Color: Orange to orange red; Flower: Pink, double, fragrant .
Double pink flowers smother the branches of this very narrow, upright cherry in early spring. The floral display from First Blush gives way to dark green, finely textured, disease resistant leaves that turn bright orange to orange red in autumn. Fact Sheet
Kwanzan Cherry – Prunus serrulata ‘Kwanzan’ – Zone: 5-9; Height: 30’; Spread: 20’; Shape: Stiffly vase shaped; Foliage: Dark green; Fall Color: Bronze-orange to orange-red; Flower: Double, rosy pink in clusters;
Fruit: Seedless.
Kwanzan cherry has large pink flowers that make it the showiest of all the cherries in spring and it remains the most hardy and popular double flowering cherry available today. Fact Sheet
Merlot® Birdcherry – Prunus padus ‘Drietree’ – Zone: 3-7; Height: 30'; Spread: 18'; Shape: Upright oval;
Foliage: Leaves emerge green, turn purple in summer; Fall Color: Red to reddish purple; Flower: White, fragrant, in 4" long drooping clusters.
Strongly upright with straight central leader, Merlot® maintains a symmetrical, upright oval shape. Its form makes it easier to manage and its foliage is deeper purple than similar cultivars. Fact Sheet
Pink Flair® Cherry – Prunus sargentii ‘JFS-KW58’ – Zone: 3b-7; Height: 25'; Spread: 15'; Shape: Upright
narrow vase; Foliage: Dark green; Fall Color: Orange-red; Flower: Single pink, in clusters; Fruit: Purple black drupe which ripen in summer.
Narrow and upright in form, but compact in height, Pink Flair flowering cherry is well suited for urban landscapes. It avoids frost damage by flowering a week or two later than is typical of the species and has proven to be the hardiest of the flowering cherries. Fall color is consistently bright orange-red, and its handsome bark and upright symmetrical form provide winter appeal. Fact Sheet
Royal Burgundy Cherry – Prunus serrulata ‘Royal Burgundy’ – PP# 6520 – Zone: 5-9; Height: 20'; Spread: 15'; Shape: Broadly vase shaped; Foliage: Deep purple; Fall Color: Bronze-purple; Flower: Double, magenta-pink; Fruit: Seedless.
Royal Burgundy is a purple leaf form of Kwanzan Cherry. Slightly slower growing than Kwanzan, the flowers of Royal Burgundy are a darker tint and its foliage is unique among the cherries. Fact Sheet
Sargent Cherry – Prunus sargentii – Zone: 4-7; Height: 30'; Spread: 30'; Shape: Upright, spreading branches, rounded crown; Foliage: Shiny dark green; Fall Color: Bronze orange to orange-red; Flower: Single pink, in clusters; Fruit: Purple black drupe which ripen in summer.
Sargent displays some of the best fall color to be found among the cherries. It has nice polished mahogany colored bark and is hardier than other Japanese cherries. Fact Sheet
Snow Goose Cherry – Prunus ‘Snow Goose’ – Zone: 5-8; Height: 20’; Spread: 20’; Shape: Upright when young, becoming wider with age; Foliage: Bright green; Fall Color: Orange; Flower: Pure white, single.
Snow Goose cherry has pure white flowers that bloom before its clean, bright green leaves unfold. This cherry is resistant to common cherry foliage diseases and the form of this strongly upright tree widens considerably with age. Fact Sheet
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 .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 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
Flowering cherry trees are a long time favorite that does well in the city, once they become established. Most of the species and cultivars transplant with ease. The description that follows provides a summary of similarities that all the species and cultivars possess. The bottom half of this article describes the author's opinion of the best of the flowering cherry cultivars for growing in the city. This information has been gathered from personal observations of the author, living in Massachusetts, Zone 6, and information provided by J. Frank Schmidt & Son.
Bloom Period: Spring
Fruit: Small, color varies with cultivar
Bark: Often smooth and reddish
Hardiness Zone: Varies according to the cultivar
Growth Rate: Medium to fast
Pest Resistance: Seldom infected with foliage diseases or insects
Salt Resistance: Good to excellent
Planting: Easy to transplant bare root and B&B, suitable for planting in CU-Structural Soil
Pruning: Prune for clearance only
Design Uses: Excellent for street trees and trees in small yards, good as a specimen or in groupings
Akebono Cherry – Prunus x yedoensis ‘Akebono’ – Zone: 5-9; Height: 25'; Spread: 25'; Shape: Upright, spreading; Foliage: Medium green; Fall Color: Yellowish; Flower: Delicate pink; Fruit: occasional shiny black fruits.
Clouds of airy pink blossoms crowd the upright spreading branches of Akebono cherry. The blooms have a stronger pink tint than the better-known Yoshino Cherry. Fact Sheet
Amanogawa Cherry – Prunus serrulata ‘Amanogawa’ – Zone: 5-9; Height: 20’; Spread: 6’; Shape: Columnar,
fastigiate branching; Foliage: Green; Fall Color: Bronze; Flower: Pale pink, semi-double.
Very narrow and tightly upright in growth, Amanogawa cherry forms a column of light pink flowers in the spring. Sometimes this tree will produce small black fruits. Fact Sheet
Canada Red Improved Chokecherry – Prunus virginiana ‘Canada Red’ – Zone: 2-6; Height: 25’; Spread: 20’;
Shape: Upright spreading, rounded; Foliage: Leaves emerge green, turn purple in summer; Fall Color: Red to reddish purple; Flower: Small white, in long clusters; Fruits: red, becoming dark purple.
A very cold hardy tree, Canada Red Improved is used for its foliage which changes from green in spring to dark purple as the weather warms, then intensifies to reddish in autumn. Fact Sheet
First Blush™ Cherry – Prunus ‘JFS-KW14’ – Zone: 5-9; Height: 25'; Spread: 12'; Shape: Upright narrow oval;
Foliage: Dark green; Fall Color: Orange to orange red; Flower: Pink, double, fragrant .
Double pink flowers smother the branches of this very narrow, upright cherry in early spring. The floral display from First Blush gives way to dark green, finely textured, disease resistant leaves that turn bright orange to orange red in autumn. Fact Sheet
Kwanzan Cherry – Prunus serrulata ‘Kwanzan’ – Zone: 5-9; Height: 30’; Spread: 20’; Shape: Stiffly vase shaped; Foliage: Dark green; Fall Color: Bronze-orange to orange-red; Flower: Double, rosy pink in clusters;
Fruit: Seedless.
Kwanzan cherry has large pink flowers that make it the showiest of all the cherries in spring and it remains the most hardy and popular double flowering cherry available today. Fact Sheet
Merlot® Birdcherry – Prunus padus ‘Drietree’ – Zone: 3-7; Height: 30'; Spread: 18'; Shape: Upright oval;
Foliage: Leaves emerge green, turn purple in summer; Fall Color: Red to reddish purple; Flower: White, fragrant, in 4" long drooping clusters.
Strongly upright with straight central leader, Merlot® maintains a symmetrical, upright oval shape. Its form makes it easier to manage and its foliage is deeper purple than similar cultivars. Fact Sheet
Pink Flair® Cherry – Prunus sargentii ‘JFS-KW58’ – Zone: 3b-7; Height: 25'; Spread: 15'; Shape: Upright
narrow vase; Foliage: Dark green; Fall Color: Orange-red; Flower: Single pink, in clusters; Fruit: Purple black drupe which ripen in summer.
Narrow and upright in form, but compact in height, Pink Flair flowering cherry is well suited for urban landscapes. It avoids frost damage by flowering a week or two later than is typical of the species and has proven to be the hardiest of the flowering cherries. Fall color is consistently bright orange-red, and its handsome bark and upright symmetrical form provide winter appeal. Fact Sheet
Royal Burgundy Cherry – Prunus serrulata ‘Royal Burgundy’ – PP# 6520 – Zone: 5-9; Height: 20'; Spread: 15'; Shape: Broadly vase shaped; Foliage: Deep purple; Fall Color: Bronze-purple; Flower: Double, magenta-pink; Fruit: Seedless.
Royal Burgundy is a purple leaf form of Kwanzan Cherry. Slightly slower growing than Kwanzan, the flowers of Royal Burgundy are a darker tint and its foliage is unique among the cherries. Fact Sheet
Sargent Cherry – Prunus sargentii – Zone: 4-7; Height: 30'; Spread: 30'; Shape: Upright, spreading branches, rounded crown; Foliage: Shiny dark green; Fall Color: Bronze orange to orange-red; Flower: Single pink, in clusters; Fruit: Purple black drupe which ripen in summer.
Sargent displays some of the best fall color to be found among the cherries. It has nice polished mahogany colored bark and is hardier than other Japanese cherries. Fact Sheet
Snow Goose Cherry – Prunus ‘Snow Goose’ – Zone: 5-8; Height: 20’; Spread: 20’; Shape: Upright when young, becoming wider with age; Foliage: Bright green; Fall Color: Orange; Flower: Pure white, single.
Snow Goose cherry has pure white flowers that bloom before its clean, bright green leaves unfold. This cherry is resistant to common cherry foliage diseases and the form of this strongly upright tree widens considerably with age. Fact Sheet
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 .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 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.
Dealing with
Poor Soils
By Larry Simpson
The scientific term “mycorrhiza” literally translated from Greek and Latin means “fungus root”. It is an appropriate description for this very special symbiotic tree/root relationship that dates back millions of years and actually played a key role in allowing plants to become established on terrestrial habitats. Mycorrhizal fungi persist today in over 90% of the world’s tree species. Through a beneficial symbiosis, host trees are accorded far better uptake of nutrients and water from the soil. In return, the tree “feeds” sugars and other products of photosynthesis to the fungi, which are unable to synthesize their own nourishment.
Since World War II, agronomy technology has focused primarily on the development of chemical and mechanical approaches to improving tree performance. Nutrient needs have been addressed using synthetic fertilizers. Weed suppression has been accomplished with herbicides. Tree diseases are now controlled using an array of chemical pesticides. Scientists now recognize that mycorrhizal fungi are a key to optimum root efficiency and that tree roots in natural habitats are actually a complex mixture of both fungi and tree organisms.
Parts of the mycorrhizal fungus consists of microscopic filaments called hyphae. The individual hyphae are approximately 1/25th the diameter of a human hair and can grow up to 18-24 inches (50-60 cm) in length. These strands originate from within the root cells of the host tree, spreading and branching into the surrounding soil, while greatly increasing the surface area of the root system.
How They Work
The effect of a tree/fungus association on the root system of a tree can be dramatic. Under this relationship, most of the absorbing area of the root system actually becomes fungal hyphae. Hyphae are far thinner than roots or root hairs and are able to penetrate the tiniest pores and fissures in the soil. When the hyphae touch another root, whether from the same tree or another tree, they begin to colonize that root, which starts to grow more hyphae. Before long, the numbers of hyphae on a root system can be vast. The resulting nutrient uptake efficiency of a tree is increased considerably. Research confirms that mycorrhizae are especially important in mobilizing phosphorus, nitrogen, zinc, iron, calcium, magnesium, manganese, sulfur, and other tightly bound soil nutrients. The hyphae produce enzymes that can release nutrients from recalcitrant chemical bonds, then transport them in available forms back to the tree roots. The host tree’s uptake and utilization of fertilizers also becomes more efficient, often leading to significant savings in fertilizer costs.
The hyphae also absorb water during moist periods, then retain and slowly release it to the tree during periods of drought. Tree systems in natural areas generally achieve levels of drought tolerance far exceeding those found in urban areas partially due to the enormous web of mycorrhizal hyphae which act like a giant sponge to protect the tree communities from extreme soil moisture deficits. The declining availability of water and its ever-increasing cost are formidable issues facing today’s arborist. Mycorrhizal fungi can be a powerful tool to enhance water-use efficiency.
The fungus/root relationship also plays a definitive role in the host tree’s natural defense against fungal root diseases such as phytophthora, fusarium, phythium, rhizoctonia, and verticillium. Mycorrhizal fungi produce and release suppressive antibiotic exudates that inhibit infection by these and other fungal root pathogens. Furthermore, researchers have found that that mycorrhizae further defend root systems by forming a thin, leathery protective layer of chitin (the same tough material as in insect shells) over the outside of root tissue to deter pathogen infection.
Introducing Mycorrhizae
Many activities on the land are known to suppress the biological activity in soils, including the construction of buildings, sidewalks, and streets. Soil fungicide use, chemical fertilizer applications, compaction, and soil erosion are also factors that may contribute adversely to populations of beneficial mycorrhizal fungi. Soil testing worldwide indicates that many intensively managed urban areas lack adequate populations of mycorrhizal fungi.
Fortunately mycorrhizal inoculants are now available which allow arborists to easily and inexpensively treat urban trees. The application of a quality inoculum is required only once in the life of the tree. Treatment of young trees is quite economical and inoculating bare root trees at planting time has become a common practice among many city foresters. The relatively recent development of liquid or soluble powder inoculants makes it easy to spray or root-dip the young trees shortly before planting.
Established trees may also be successfully treated, although the cost is somewhat greater because more inoculum is required to treat the larger root mass. However, given the long period of returned benefits, many arborists find such treatment cost effective. To treat established trees, a liquid inoculum is sprayed onto the soil under the tree canopy and over those areas with abundant feeder roots. Rainfall and irrigation water are particularly effective and will carry the dormant mycorrhizal spores throughout the soil profile until they contact living roots. This contact stimulates the spores to begin the colonization process and eventually the hyphae grow and spread throughout the entire root system. Note that the inoculum must contact the soil, so foliar applications will not work.
Enhanced nutrient uptake, improved moisture efficiency, and fungal root disease suppression are among the primary advantages mycorrhizae can contribute to tree management operations. By improving tree growth and reducing costs, these fungi offer natural and powerful solutions to some of an arborists most persistent and vexing challenges.
Larry Simpson is with Mycorrhizal Applications, Inc.
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 .5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, Aerial Lift 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 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 Larry Simpson
The scientific term “mycorrhiza” literally translated from Greek and Latin means “fungus root”. It is an appropriate description for this very special symbiotic tree/root relationship that dates back millions of years and actually played a key role in allowing plants to become established on terrestrial habitats. Mycorrhizal fungi persist today in over 90% of the world’s tree species. Through a beneficial symbiosis, host trees are accorded far better uptake of nutrients and water from the soil. In return, the tree “feeds” sugars and other products of photosynthesis to the fungi, which are unable to synthesize their own nourishment.
Since World War II, agronomy technology has focused primarily on the development of chemical and mechanical approaches to improving tree performance. Nutrient needs have been addressed using synthetic fertilizers. Weed suppression has been accomplished with herbicides. Tree diseases are now controlled using an array of chemical pesticides. Scientists now recognize that mycorrhizal fungi are a key to optimum root efficiency and that tree roots in natural habitats are actually a complex mixture of both fungi and tree organisms.
Parts of the mycorrhizal fungus consists of microscopic filaments called hyphae. The individual hyphae are approximately 1/25th the diameter of a human hair and can grow up to 18-24 inches (50-60 cm) in length. These strands originate from within the root cells of the host tree, spreading and branching into the surrounding soil, while greatly increasing the surface area of the root system.
How They Work
The effect of a tree/fungus association on the root system of a tree can be dramatic. Under this relationship, most of the absorbing area of the root system actually becomes fungal hyphae. Hyphae are far thinner than roots or root hairs and are able to penetrate the tiniest pores and fissures in the soil. When the hyphae touch another root, whether from the same tree or another tree, they begin to colonize that root, which starts to grow more hyphae. Before long, the numbers of hyphae on a root system can be vast. The resulting nutrient uptake efficiency of a tree is increased considerably. Research confirms that mycorrhizae are especially important in mobilizing phosphorus, nitrogen, zinc, iron, calcium, magnesium, manganese, sulfur, and other tightly bound soil nutrients. The hyphae produce enzymes that can release nutrients from recalcitrant chemical bonds, then transport them in available forms back to the tree roots. The host tree’s uptake and utilization of fertilizers also becomes more efficient, often leading to significant savings in fertilizer costs.
The hyphae also absorb water during moist periods, then retain and slowly release it to the tree during periods of drought. Tree systems in natural areas generally achieve levels of drought tolerance far exceeding those found in urban areas partially due to the enormous web of mycorrhizal hyphae which act like a giant sponge to protect the tree communities from extreme soil moisture deficits. The declining availability of water and its ever-increasing cost are formidable issues facing today’s arborist. Mycorrhizal fungi can be a powerful tool to enhance water-use efficiency.
The fungus/root relationship also plays a definitive role in the host tree’s natural defense against fungal root diseases such as phytophthora, fusarium, phythium, rhizoctonia, and verticillium. Mycorrhizal fungi produce and release suppressive antibiotic exudates that inhibit infection by these and other fungal root pathogens. Furthermore, researchers have found that that mycorrhizae further defend root systems by forming a thin, leathery protective layer of chitin (the same tough material as in insect shells) over the outside of root tissue to deter pathogen infection.
Introducing Mycorrhizae
Many activities on the land are known to suppress the biological activity in soils, including the construction of buildings, sidewalks, and streets. Soil fungicide use, chemical fertilizer applications, compaction, and soil erosion are also factors that may contribute adversely to populations of beneficial mycorrhizal fungi. Soil testing worldwide indicates that many intensively managed urban areas lack adequate populations of mycorrhizal fungi.
Fortunately mycorrhizal inoculants are now available which allow arborists to easily and inexpensively treat urban trees. The application of a quality inoculum is required only once in the life of the tree. Treatment of young trees is quite economical and inoculating bare root trees at planting time has become a common practice among many city foresters. The relatively recent development of liquid or soluble powder inoculants makes it easy to spray or root-dip the young trees shortly before planting.
Established trees may also be successfully treated, although the cost is somewhat greater because more inoculum is required to treat the larger root mass. However, given the long period of returned benefits, many arborists find such treatment cost effective. To treat established trees, a liquid inoculum is sprayed onto the soil under the tree canopy and over those areas with abundant feeder roots. Rainfall and irrigation water are particularly effective and will carry the dormant mycorrhizal spores throughout the soil profile until they contact living roots. This contact stimulates the spores to begin the colonization process and eventually the hyphae grow and spread throughout the entire root system. Note that the inoculum must contact the soil, so foliar applications will not work.
Enhanced nutrient uptake, improved moisture efficiency, and fungal root disease suppression are among the primary advantages mycorrhizae can contribute to tree management operations. By improving tree growth and reducing costs, these fungi offer natural and powerful solutions to some of an arborists most persistent and vexing challenges.
Larry Simpson is with Mycorrhizal Applications, Inc.
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 .5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, Aerial Lift 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 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.