Archive #53 from Online Seminars for Municipal Arborists
November/December 2013
Sections
Tree of the Seminar
By Len Phillips
Unlike most saucer magnolias, Galaxy Magnolia has lavender to pink and purple flowers that open late enough to avoid late spring frost damage. The following information has been gathered from personal observations of the author, living in Massachusetts, Zone 6, and information provided by J. Frank Schmidt & Son.
Botanical Name: Magnolia ‘Galaxy’
Trade Name: Galaxy Magnolia
Parentage: M. liliflorax M. sprengeri ‘Diva’selected and released at the U.S. National Arboretum by Dr. Frank Santamour
Introduction: 1963
Height: 30' -- 50'
Spread: 10' -- 15'
Form: Tree form and shrub form available, upright habit with straight central leader, pyramidal to oval form
Bloom Period: April, before leaves but after spring frost
Flower: 3"-- 6" diameter reddish to purple, to pink, fragrant
Fruit: Seldom produces the 6” long dark pod that is typical of the species
Summer Foliage: Dark green in summer, thick when grown in full sun, large leaves 4"-- 7" long
Autumn Foliage: Yellow brown in fall
Winter Color: Brown bark and the occasional seed pod provide winter interest
Bark: Brown
Habitat: M. lilifloraand M. sprengeri are both native of China
Culture: Full sun, rich, moist, acid soil
Hardiness Zone: 5-- 9
Growth Rate: Fast, full size in 30 years
Pest Problems: Minor problems
Storm Resistance: Good
Salt Resistance: Good
Planting: Fleshy roots, need deep soil, transplant B & B or container, slow to recover after planting
Pruning: Prune damaged branches at planting and 3 years later to mature form
Propagating: Hardwood cuttings in winter
Design Uses: Nice specimen, very effective with a dark background, excellent for residential landscapes, small tree for use in gardens and along city streets
Companions: Use with Boltonia, Aster, Moonbeam Coreopsis, & Baby’s Breath
Other Comments: Best grown in cold climates with northern exposure to protect blooms, heavy bloomer starting at a young age, thick when full grown, Dr. Santamour promoted this cultivar as "a street tree magnolia", because it is so tough in the urban environment.
Photo and 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 .5 CEUs for every 5 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. If you are also a Certified Forester, we will report your passing test scores to SAF for no additional cost. Tests with passing scores may be submitted only once to each organization.
Members of ISA may apply the .5 CEUs toward Certified Arborist or BCMA science credits.
Members of SAF can earn 0.5 hour Cat. 1-CT credits for every five passing test scores. SAF requires five passing test scores before reporting.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA and MTOA members may submit your ISA certification record to these organizations and receive credits one for one.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment 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.
All test scores are sent to gibneyCE.com automatically when you press ‘next’ after taking the test and reviewing your answers. You will see a sending responses message after which you will be returned to our website. It is important to go through this process for your score to be recorded properly. All passing test scores are then 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 earned 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 responses message.
Psithurism
Edited by Len Phillips
We can't see wind, only the things it moves. Likewise, we can't hear wind unless it's flowing past something that makes it vibrate. This causes it to adopt various sonic guises depending on what it interacts with. Taking a walk through a pine grove provides some of the most common and admired ways for wind to make itself heard. The sound of wind in the trees is very restorative and a mysterious voice from which the forest speaks to us, and that to lie or sit in the forest for an hour at a time listening to the wind is an experience worth going far to seek. The sound of wind in the trees and rustling of leaves has been termed psithurism (sith-err-iz-um). The sonic qualities of psithurism seem to smudge the border between music and noise. Psithurism has fascinated poets and writers for generations. What follows are some examples of the romantic side of psithurism.
The American poet Henry Wadsworth Longfellow(1807-1882) described the sound in “A Day of Sunshine”:
“I hear the wind among the trees
Playing celestial symphonies;
I see the branches downward bent,
Like keys of some great instrument.”
The type of leaf, the season and the species of tree all work together to create a unique sound,or as John
Muir put it: “Winds are advertisements of what they touch”. He described how, in the wind, each tree expressed itself in its own way, “singing its own song, and making its own peculiar gestures”. Of all the tree species the sounds of the pine seems to have captured the imagination of naturalists more than any other.
Muir suggests pines are the best interpreters of the winds. “They are mighty waving golden-rods, ever in tune, singing and writing wind music all their long century lives." (A Wind Storm in the Forests of the Yuba, 1878)
Henry David Thoreau also had an affinity for the wind through the pines: “The white pines in the horizon, either single trees or whole wood, are particularly interesting. The wind is making passes over them, magnetizing and electrifying them… This is the brightening and awakening of the pines… As if in this wind-storm of March a certain electricity was passing from heaven to earth through the pines and calling them to life”. (Journal of Henry David Thoreau 1855-1861)
Eastern thinkers also noted the distinctiveness of pines. Shunryu Suzuki (1904-1971), a Zen monk and teacher, describes with typical equity, psithurism and the mind: “When we hear the sound of the pine trees on a windy day, perhaps the wind is just blowing, and the pine tree is just standing in the wind. That is all that they are doing. But the people who listen to the wind in the tree will write a poem, or will feel something unusual. That is, I think, the way everything is.”
Finally, perhaps the earliest and loveliest writing on this subject is by Liu Chi (1311-1375), an important scholar under the Yuan and the Ming Dynasties, who wrote that: “Among plants and trees, those with large leaves have a muffled sound; those with dry leaves have a sorrowful sound; those with frail leaves have a weak and unmelodic sound. For this reason, nothing is better suited to wind than the pine.”
Liu Chi continues to say, “Now, the pine as a species has a stiff trunk and curled branches, its leaves are thin, and its twigs are long. It is gnarled yet noble, unconstrained and overspreading, entangled and intricate. So when wind passes through it, it is neither obstructed nor agitated. Wind flows through smoothly with a natural sound. Listening to it can relieve anxiety and humiliation, wash away confusion and impurity, expand the spirit and lighten the heart, make one feel peaceful and contemplative, cause one to wander free and easy through the skies and travel along with the force of Creation. It is well suited to gentlemen who seek pleasure in mountains and forests, delighting in them and unable to abandon them.... Gazing at the pines soothed my eyes; listening to the pines soothed my ears. I escaped from my duties and with this leisure time wandered free and easy here and there without any worldly concerns to perplex the mind. I can feel happy here and pass the entire day this way.” “If you like the outdoors and wish to enjoy psithurism every day, don't live in the
city.”
Source
- Winson, Adam, Arboriculturist, Blog titled “Psithurism”, January 2013.
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 .5 CEUs for every 5 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. If you are also a Certified Forester, we will report your passing test scores to SAF for no additional cost. Tests with passing scores may be submitted only once to each organization.
Members of ISA may apply the .5 CEUs toward Certified Arborist or BCMA science credits.
Members of SAF can earn 0.5 hour Cat. 1-CT credits for every five passing test scores. SAF requires five passing test scores before reporting.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA and MTOA members may submit your ISA certification record to these organizations and receive credits one for one.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment 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.
All test scores are sent to gibneyCE.com automatically when you press ‘next’ after taking the test and reviewing your answers. You will see a sending responses message after which you will be returned to our website. It is important to go through this process for your score to be recorded properly. All passing test scores are then 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 earned 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 responses message.
Protecting Trees During Construction
Edited by Len Phillips
Shade trees have an extensive root system that is required to maintain the health of the tree and trees add to the value of property. Therefore, during construction, efforts should be made to protect and preserve established, healthy shade trees and their root systems. Any construction work in the area near trees, should be done with extreme care. The majority of roots are located within the top 12 inches (30 cm) of soil and extends past the dripline of the tree. The dripline makes a circle around the tree and must be considered a protected root zone.
Saving a Tree
The following items must be considered to decide whether it is better to save the tree and work around it, or remove the tree and replace it with a smaller, younger tree, after the construction is complete.
- Age: Younger trees will survive soil and grade changes better than older, more mature trees.
- Disturbance Sensitivity: Trees vary in sensitivity when the soil and their roots are cut or disturbed.
- Soil Compaction: Trees vary in sensitivity, but generally become stressed due to the soil around their roots being compacted.
- Severity of Change: The amount of grade change or root loss is a major factor to consider.
- Tree Health: If trees are already stressed the likelihood of surviving a major change in root loss or grade change is small.
Preventing Injury
Preventing damage is less costly than correcting it. Few developers and builders are aware of the way tree roots grow and what is needed to protect them. Before construction begins, the arborist must meet with the planner to decide which trees can be saved and what design modifications must be taken to help preserve the trees that are to remain. Next, install highly-visible barricades and signs around the trees and root zone areas to be protected. The optimal size of barricaded areas varies according to tree species, size, and construction project. For example:
- For recently planted trees (one to four years), the area to be protected should be within the dripline.
- For minimal protection of trees older than four years, barricades should extend beyond the dripline.
- For each inch of the tree’s trunk's diameter, the protection area should extend one foot of radius.
- For additional protection, a temporary layer of wood chips, 4 to 6 inches (10 – 15 cm) deep, should be placed around each tree prior to placement of the barricades.
- Examine trees and barricades at least once a week during the entire construction time frame; more often during the active construction period.
Types of tree injury caused by mechanized equipment include:
- Bark removal or "skinning" of the trunk can be caused by any type of equipment.
This can easily kill the tree if the damage is extensive and it is not treated
or repaired within a very few minutes of the injury. - Breakage of branches may make the tree unsightly and removing too many leaves will cause stress and future decline of the tree.
- Surface grading removes surface vegetation and the topsoil that contains a tree's roots.
- Trenching for utilities can also cause substantial root damage and should be done far away from existing trees. In new developments, this can be done easily. Where the trench must pass under or near a tree, substantial injury can be avoided by using a power auger to bore a tunnel under the roots. If trenching is unavoidable, place the trench as far from the trunk as possible (minimum 8 feet) (2 m), while cutting as few roots as possible. Cleanly prune cut roots and refill trenches as soon as possible to prevent excessive moisture loss. Wounds make the tree highly susceptible to root pathogens and decay fungi. Decline and death can result if more than 40% of the roots are damaged or killed. Stressed trees are also more susceptible to insect attacks such as from bark beetles and borers.
Avoid Soil Compaction
After a tree is established, any activity that changes the soil condition is extremely detrimental to its health. Construction traffic compacts soil most severely near the surface, where the majority of tree roots are growing. Soil compaction decreases soil permeability, reduces the amount of pore space, and interferes with essential gas exchange as well as surface and subsurface drainage. When root growth is restricted by compacted soils, less nutrients and water are available for plant growth which results in reduced tree vigor and possible death. Decline and dieback may gradually appear over a period of years because of soil compaction.
It is much easier to avoid soil compaction than to correct it. Keep construction traffic and material storage away from tree root areas and out of the barricaded areas. The 4 to 6 inch (10 – 15 cm) layer of wood chips around all protected trees as mentioned above will help reduce compaction from vehicles that inadvertently cross the barricades.
Digging Trenches
Trenches should only be dug on one side of the tree. To find the minimum distance from the tree trunk that the trench can be dug, determine the diameter of trunk at breast height (dbh) by measuring the diameter or width of the tree trunk. Multiply the dbh in inches by one foot (30 cm) to get minimum distance from tree for there to be a trench. Keep in mind this is the minimum distance and it is always best for the health of the tree to maximize this distance to beyond the dripline.
Some recent research has indicated that if the trench is going to remove more than one quarter of the tree's roots, the best place to locate a trench is directly under the tree trunk. This will minimize root loss provided
the excavating equipment starts one foot on either side of the trunk and the tunnel at the bottom of the trench, under the tree trunk is hand dug to allow the pipe to run directly under the tree.
Augering
When augering for fence posts, signs, etc., use the same distance calculation as was used for digging trenches. This should be a minimum distance. If possible, extend this outward a few feet or better still, outside the dripline.
General Rules for Cutting Roots
- Water tree a few days before construction activities to soak the soil and hydrate the tree roots, but not within two days before construction begins.
- If soil is wet, any weight will compact the soil pores which will cause more stress on the tree's roots.
- Make sure cuts to the roots are done with hand tools that will make clean, quick cuts. Do not use large equipment like backhoes and bulldozers to tear the roots off the tree.
- Do not disturb roots any more than necessary. Twenty percent of the tree's roots can be cut before any signs of stress will appear. Keep in mind that tree roots do extend outside of the protected root zone and beyond the dripline.
- Make sure cut roots are covered with soil and wood chips as soon as possible after the pipe is laid. If roots are going to be exposed for more than an hour, cover the roots with a damp cloth. Be sure to keep cloth moist until soil and mulch can be used for permanent cover.
- Water the tree thoroughly when job is done. This means wetting the top 12 inches (30 cm) of soil within the entire tree dripline.
- Put a permanent 3 foot (1m) (minimum) diameter ring of mulch around base of tree. Mulch 3 – 5 inches (8 – 12 cm) deep but keep the mulch 6 inches (15 cm) away from trunk. Wood chips, shredded bark or leaves, and ground corn cobs are examples of good products that can be used for mulch. Most types of mulch break down in time, so it is necessary to replenish the mulch from year to year.
Grade Cuts
If more than 12 inches (30 cm) of soil is to be removed from an area containing tree roots, build a retaining wall to reduce the amount of grade change within the protected root zone. Also, if needed, create steps of grade changes.
After building the retaining wall, back fill with soil, and mulch the soil surface around the tree. Also, do not remove soil within 3 feet (1 m) of the trunk. If these rules will not work, remove tree and plant a new one once
the grade change has been made.
Filling Grade
Before raising the grade within the protected root zone, consider soil compaction. No more than 24 inches (65 cm) of soil should be added within the protected root zone. When adding soil to increase the grade within the
protected root zone, never allow the excess soil to touch the trunk or base of the tree. This will cause rot, which can kill the tree no matter how healthy it is.
To keep soil away from the base of the tree, build a retaining wall around and 3 feet (1 m) away from the trunk. When adding soil, it is advisable to lay drainage pipes in a radial pattern to provide air flow from the wall and the lower half of new fill soil should be a mix of coarse sand and shredded bark.
If the fill is going to be deeper than suggested above, build the retaining wall on or outside the dripline. Back-filling should be done as mentioned above, with the lower half the depth being a mix of coarse sand and shredded bark. Aeration is necessary when adding large amounts of fill.
Adding or Removing Soil on One Side of the Tree
If it is necessary to cut or fill on only one side of the tree, use the same methods mentioned above. Still do not work closer than 3 feet (1 m) from the trunk of the tree.
Aeration
Aerate within the protected root zone before and after grade changes. Starting 3 feet (1 m) from the base of the tree, drill 2-inch (5 cm) diameter holes into the soil about 1 to 1-1/2 feet (30 – 50 cm) deep. Drill the holes in a circle 3 feet (1 m) away from the trunk, spacing them two feet (60 cm) apart, and then go out 5 feet (1.5 m) and drill again in a circle. Continue every 2 feet (60 cm) within the protected root zone. Use the porous soil mentioned above to fill the holes.
Under the Canopy
- Do not add more than 6" (15 cm) total of soil and/or mulch.
- Keep mulch 6” (15 cm) away from base of tree.
- Never till soil under canopy.
- Do not overwork the soil under the tree.
- Work soil with hands and hand tools only, no large equipment.
- Preserve ground covers and/or mulch around the tree that protect its roots and the soil from compaction and maintain soil moisture.
- Do not plant anything within 3 feet (1 m) of the tree trunk that will compete with the tree for moisture and nutrients, such as another tree or large shrubs. Ground covers, perennials, and small shrubs can be beneficial to the tree. They act as a barrier to soil compaction and improving moisture content by shielding the soil from direct sun exposure.
- Avoid planting anything that will be more than one-third the mature height of the tree.
- Avoid cutting roots from one inch (2 cm) diameter and up. If roots are encountered, move planting hole over until you can dig without encountering large roots.
Tips for Tree Care Before and After
The best time to prepare a tree for construction activities, within the root zone, is a year before the work begins. Trees store water and nutrients for times of need. These times can be the spring growth surge, during droughts, after a hailstorm, etc. So extra stores of water and nutrients will create a healthier, stronger tree and will increase survival following the stress of damaging work. Trees should be watered a few days before work is to begin and again as soon as possible after the work is done. Watering should be done thoroughly and deeply. Finally, remember to contact the local utility companies to find out where it is safe to dig before digging.
Sources
- Bracewell, Sara K. “Protecting Existing Trees During Construction”, University of Minnesota, Department of Horticultural Science, 2006.
- Coder, Dr. Kim D., “Tree Conservation during Site Development”, Warnell School of Forestry & Natural Resources, University of Georgia, 2010.
- Dennis, C., and W.R. Jacobi, “Protecting Trees During Construction”, Colorado State University Extension, April 2013.
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 .5 CEUs for every 5 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. If you are also a Certified Forester, we will report your passing test scores to SAF for no additional cost. Tests with passing scores may be submitted only once to each organization.
Members of ISA may apply the .5 CEUs toward Certified Arborist, Tree Worker Specialist, Utility Specialist, Municipal Specialist, or BCMA practice credits.
Members of SAF can earn 0.5 hour Cat. 1-CT credits for every five passing test scores. SAF requires five passing test scores before reporting.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA and MTOA members may submit your ISA certification record to these organizations and receive credits one for one.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment 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.
All test scores are sent to gibneyCE.com automatically when you press ‘next’ after taking the test and reviewing your answers. You will see a sending responses message after which you will be returned to our website. It is important to go through this process for your score to be recorded properly. All passing test scores are then 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 earned 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 responses message.
Cultivars of Tupelo
By Len Phillips
Tupelo or Black Gum has rich, green, glossy foliage that ignites with brilliant autumn tones of scarlet to maroon, yellow, and orange. Fissured gray bark provides winter interest. Adaptable to urban conditions including compacted and poorly drained soils and occasional drought. The following comments pertain to all of the cultivars mentioned below.
Botanical Name: Nyssa sylvatica
Common Name: Tupelo, Black Gum,or Sour Gum
Family: Nyssaceae
Form: Pyramidal shape in youth, horizontal branches with age, highly variable
Bloom Period: Spring, at leaf break
Flower: Small, 2 – 4 flowers per cluster, not attractive
Fruit: Pendulous, black drupe, ½" long, eaten by birds and mammals in fall, some cultivars are seedless
Summer Foliage: Dark green, glossy
Autumn Foliage: Varies according to the cultivar
Winter Color: Fruits persist until November, dark scaly bark
Bark: Dark gray to black, thick blocks
Habitat: Northeast US and Canada, south to Florida and Texas
Culture: Moist, well drained, acid soil, will tolerate dry shallow soil
Growth Rate: Slow to medium, 12' after 15 years
Pest Problems: Nothing serious, butsusceptible to fusarium, Phytophthora root rot, rust, and verticillium
Storm Resistance: Good
Salt Resistance: Good
Planting: Difficultto transplant, best as B&B in early spring or in containers if small
Pruning: Prune only in the fall
Design Uses: Excellent specimen for homes, streets with limited pollution, good in naturalized setting
Companions: Use with fernsand evergreen groundcover
Other Comments: One of the most beautiful trees in the fall
Fact Sheet: J. Frank Schmidt & Son
Of the approximately 12 known cultivars, only the following are currently available at selected nurseries. Searching may be required to find the cultivar you want.
Afterburner® Tupelo Nyssa sylvatica‘David Odom’– Zone: 5 – 9, height: 35’, spread: 20’, shape: upright pyramidal to oval, fall color: bright red. The symmetrical, uniform branch structure and straight central
leader make this cultivar both easier to grow and more beautiful in the landscape. The high gloss foliage shines through the summer and then turns bright red in fall, still burning brightly after most seedling tupelo have defoliated. Fact Sheet
Autumn CascadesTupelo Nyssa sylvatica' Autumn Cascades' – Zone: 4 – 9, height: 20' – 25’, spread: 10' – 12’, shape: pendulous, foliage: large, glossy, healthy looking, dark green leaves, fall color: yellow and scarlet. Autumn Cascades is a strong growing Australian selection of Black Gum with a distinct weeping, pendulous habit. Autumn Cascades forms a magnificent specimen tree especially suitable for restricted spaces. Specialty nurseries are beginning to produce this new, strongly weeping form that shows good fall color. Once accepted by horticulturists, this plant may become a worthy addition to a list of weeping tree selections.
Gum Drop® Tupelo Nyssa sylvatica‘JFS-PN Legacy1’– Zone: 5 – 9, height: 30', spread: 20', shape: upright oval, fall color: bright red, fruit: seedless, foliage: glossy dark green. Bright red autumn leaves and upright
form distinguish this outstanding tupelo selected from the fields of Princeton Nursery. Improved density and slightly compact branching are reasons to choose it over the highly variable trees grown from seed. Fact Sheet
Miss Scarlet Tupelo Nyssa sylvatica 'Miss Scarlet' – Zone: 4 – 9, height: 50’, spread: 30’, shape: oval, spreading with a high canopy, foliage: deep green, fall color: red, orange or multicolored. This is a selection notable for its quality foliage and abundant production of bluish fruit. This tree will live more than 150 years
Red Rage® Tupelo Nyssa sylvatica ‘Haymanred’– Zone: 5 – 9, height: 35', spread: 20', shape: broadly pyramidal, fall color: bright red, fruit: seedless. Discovered by plantsman Mike Hayman in southern Indiana, Red Rage® features deep green, high gloss summer foliage that resists leaf spot, then turns bright red with the onset of fall weather. Fact Sheet
Red Red Wine Tupelo(also listed as 'Red Wine') Nyssa sylvatica 'Red Red Wine' – This new cultivar from Australia is not commonly available and is reportedly notable for the red coloring of the new growth, which becomes more subdued with age. Look for it in selected nurseries in a few years.
Wildfire Tupelo ‘Wildfire’– Zone: 6 – 10, height: 40’, spread: 25’, shape: broadly pyramidal to oval, foliage: red new growth, fall color: yellow-orange to purplish. This tupelo offers an extra season of brightly colored foliage. Spring brings a surprising flush of deep red new growth, which continues as long as new leaves emerge. Summer foliage is green, changing in autumn to tints of orange-yellow and purplish red. 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 .5 CEUs for every 5 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. If you are also a Certified Forester, we will report your passing test scores to SAF for no additional cost. Tests with passing scores may be submitted only once to each organization.
Members of ISA may apply the .5 CEUs toward Certified Arborist or BCMA science credits.
Members of SAF can earn 0.5 hour Cat. 1-CT credits for every five passing test scores. SAF requires five passing test scores before reporting.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA and MTOA members may submit your ISA certification record to these organizations and receive credits one for one.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment 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.
All test scores are sent to gibneyCE.com automatically when you press ‘next’ after taking the test and reviewing your answers. You will see a sending responses message after which you will be returned to our website. It is important to go through this process for your score to be recorded properly. All passing test scores are then 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 earned 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 responses message.
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Perfecting the Christmas Tree
Edited by Len Phillips
Fraser fir is the most popular Christmas tree in the United States. Their conical shape, superb needle retention, and sturdy boughs make them perfect for keeping both Christmas ornaments and tree bits off the floor. A Christmas tree spends six to ten years in the field before it is cut, and the trees are not usually planted in tree plantations until they are seedlings of at least two or three years of age. It turns out those early years of the tree’s life are its most difficult years.
Phytophthora
The Fraser fir (Abies fraseriis) is considered by many to be an ideal Christmas tree, but it is also in need of major improvements. The Department of Forestry and Environmental Resources at North Carolina State University, (NCSU) is the leading research team on dealing with Fraser fir. They are trying to make them even better by helping growers fight a worsening root fungus problem and to grow these fir trees more quickly as well as stronger and hardier. Fraser firs have no immunity againstPhytophthoraroot rot, a genus of damaging molds that cause plant roots to rot. Its Greek name means “plant destroyer,” and it can decimate crops and almost any other type of plant. For example, a Phytophthoraspecies caused the potato blight that sparked the Great Irish Famine in the mid 1800's.
To find a cure for Phytophthoraroot rot, the researchers grew Fraser fir seedlings in a greenhouse and they inoculate them with Phytophthora root rot to test their resistance, but they all died. When they tested a very genetically diverse population of Fraser fir, they all died as well. Finally, they tested 32 of the world’s fir species, and found a Japanese tree called the Momi fir that strongly resists Phytophthoraroot rot invasion, but the Momi fir makes a terrible looking and performing Christmas tree. So to make resistant trees, NCSU researchers are performing a bit of vegetation manipulation.
Grafting
Grafting is a common horticultural technique to essentially clone different plants, but in this case it’s making chimeric trees. The research team took Momi fir seedlings and cut off the tree part. Then, they grafted Fraser fir branches into the Momi fir seedling root systems by taking a grafting knife and making a vertical slit down the center. The team inserted the Fraser seedling onto the Momi root system. The newly grafted tree is wrapped in special rubber bands and covered in wax to keep it from drying out. Then the cambium between the bark and the wood can merge. The two species grow together and form one functioning tree. At last a nice looking Christmas tree resistant to Phytophthora root rot has been developed.
However, this grafting process is expensive and time-consuming. Tree growers would prefer seedlings that already have Phytophthoraroot-rot resistance, and maintain the ideal needle retention and the pretty conical shape of Fraser firs. This requires genetic engineering to develop a hybrid with all the right features to make it an ideal Christmas tree.
Genetic Engineering
When the NCSU team was testing seedlings for Phytophthoraroot-rot resistance, they went to Turkey and gathered cones from Nordmann fir trees. Seedlings from these fir trees were inoculated with Phytophthora
root-rot and the seedlings were grown in a greenhouse. Some of them can resist Phytophthora because the
activation of certain genes provide Phytophthoraresistance. This means that growers can select Nordmann fir trees that are naturally resistant to root rot, and breed them.
NCSU is not making genetically engineered Christmas trees yet. Before they can do that however, NCSU and other researchers must try to determine the genetic codes for the tree's ideal traits, from tree and cone shape to root-rot resistance, and find the genetic markers for these sequences so they can be further studied with the goal of creating a Phytophthoraroot-rot resistant Fraser fir. They are doing the DNA sequencing to understand the DNA of Fraser fir and in the long term, this may lead to a genetically engineered Christmas tree for the future. But there is still more knowledge and techniques that need to be developed before the ideal tree will be available to the industry.
The major barrier is time. To see how well Fraser fir grows, you need to wait 10 to 12 years to see if what you are growing is the Christmas tree you want. Once a good tree is found, it has to be crossed with other good trees, but it takes firs another 10 to 12 years before they become reproductively mature and able to accept crosses between a couple of Phytophthoraroot-rot resistant Fraser firs.
In the meantime, the grafted trees are now big business in North Carolina, which is home to 2,500 tree growers producing 5 to 6 million Christmas trees a year. Fraser firs are native to Appalachia, especially the craggy peaks of western North Carolina above 3,000 feet (1,000 m) in elevation. This chilly, rainy environment may have something to do with the quick closure of the trees’ stomata and small respiratory holes on the needles,. Fraser firs have adapted to live in very wet environments and once they are cut, they do not dry out like other firs and pines which is another key feature that makes them an ideal Christmas tree.
But still, every tree is unique, both in its individual history and circumstances. This is why the researchers are looking at needle retention on Phytophthora root-rot resistant Fraser firs and trying to understand how it can be manipulated through genetics. The Christmas trees of the future will be hybrids or different plant species grafted with parts borrowed and bred from the hardiest and most “Christmassy” species. Hopefully future trees will also be more reliable.
Sources:
- Boyle, Rebecca, “How Genetics Is Perfecting The Christmas Tree”, Wikimedia Commons, December, 2012.
- “How Science is Perfecting Real Christmas Trees”, Popular Science, December 2012.
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 .5 CEUs for every 5 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. If you are also a Certified Forester, we will report your passing test scores to SAF for no additional cost. Tests with passing scores may be submitted only once to each organization.
Members of ISA may apply the .5 CEUs toward Certified Arborist or BCMA science credits.
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California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
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Research Briefs 53
Edited by Len Phillips
The Relationship Between Trees and Human Health
Geoffrey H. Donovan, PhD, et. al.
A natural experiment was used to test whether a major change to the natural environment, (the loss of 100 million trees to the emerald ash borer) has influenced human mortality related to cardiovascular and lower respiratory diseases.
There is increasing evidence from multiple scientific studies that exposure to the natural environment can improve human health. Specifically, the natural environment has been shown to decrease stress, increase physical activity, and improve air quality. A recent study was made to quantify the public health effects when the emerald ash borer, Agrilus planipennis, killed tens of millions of ash (Fraxinus) trees in the region around Michigan and Ohio, US. The goal of the study was to determine the effects the loss of trees had on the local human populations. Across the 15 states in the study area, the borer was associated with an above average level of 6,113 deaths related to illness of the lower respiratory system, and 15,080 cardiovascular-related deaths. These two types of health issues were chosen because they are the first and third most common
causes of death in the U.S., and there are plausible mechanisms linking these types of deaths with trees.
The borer had a greater effect in counties whose median household income was above average. There are several possible interpretations for these results. People in wealthier counties may have greater access to ash trees, so the death of these trees has a greater impact on them. Also, urban areas within wealthier counties have more trees, or better maintain them. It also is possible that trees provide different benefits in wealthier areas. For example, the proximity to urban parks increased the sales price of homes in wealthier neighborhoods, whereas, in poor neighborhoods, houses close to parks sold for less. The parks may attract criminal behavior in poorer neighborhoods, so residents are not able to benefit from the park as much as people living in a wealthier neighborhood. In addition, risk factors such as air quality, which trees can mediate, may be different in wealthier counties.
American Journal of Preventive MedicineFebruary 2013 44(2)
Trees Call for Help
Gabe Popkin
When drought hits, trees can suffer and start a process called cavitation that makes high-pitched sounds within the tree. Scientists have recently found the key to understanding these sounds as cries for help. Because trees make many noises, scientists had not been able to discern which sounds are most worrisome. In the lab, a team of French scientists determined the ultrasonic noise is made by bubbles forming inside water-stressed trees. This discovery could help scientists figure out when trees are parched and need emergency watering,
Listening to Trees
To figure out how to listen to trees, the French scientists drew on their knowledge of how trees take in water which is essentially similar to drinking from a really long straw. The xylem relies on the attractive forces between water molecules as well as those between water and plant cells to lift liquid to the highest leaves and branches.
Because trees are so tall, the liquid in the xylem can be under intense pressure. The pressure is many times that of the atmosphere around us, but the attractive forces between neighboring water molecules keep the water column intact.
Cavitation
Imagine using a straw to slurp the last few drops from the bottom of your glass: You have to increase the pressure even more. In drought-stricken trees, this increased pressure can cause the water column to break, allowing dissolved air to form bubbles that block water flow. This process is called cavitation and while trees can withstand some, too much can be deadly.
Scientists have known for decades that microphones can pick up the noises that cavitations make. Because they could not see inside the tree, they were not certain of the origins of these sounds, which could have resulted from wood creaking or breaking or xylem cells collapsing.
To answer the question, scientists experimented and found that around half the sounds they picked up were associated with cavitation. The rest were from other processes, such as bubbles invading neighboring cells. Most important, the sound waves from each type of event made a distinct pattern. The scientists are
currently cataloging each event and the sound that goes with it.
Helping Thirsty Trees
These findings could lead to the design of a hand-held device that allows people to diagnose drought stressed trees using only microphones. Such a device may be particularly important if droughts become more common and more severe, as many global warming models predict they will. In fact, a recent study suggested that trees in many places, from tropical rain forests in South America to arid woodlands in western U.S. already live on the edge, meaning their cavitation rate is almost as high as a tree can sustain. In the near future, a device that can be attached to a tree would constantly listen for sounds of thirst. At the right moment, the device would trigger an emergency-watering system to provide relief to the tree.
National Geographic News, April 15, 2013
World's Big Trees Are Dying
The largest living organisms on the planet, the big, old trees that harbor and sustain countless birds and other wildlife, are dying. A report by three of the world's leading ecologists warns of an alarming increase in death rates among trees 100-300 years old in many of the world's forests, woodlands, savannahs, farming areas, and even in cities.
Looking around the world, the scientists found similar trends at all latitudes, in California's Yosemite National Park, on the African savannahs, in the rainforests of Brazil, the temperate forests of Europe and the boreal forests of the far north. Losses of large trees were also pronounced in agricultural landscapes and even cities, where people make efforts to preserve them.
Research is urgently needed to identify the causes of rapid losses of large old trees and strategies for improved management. Without policy changes, large old trees will diminish or disappear in many ecosystems, leading to losses of their associated biota and ecosystem functions.
The researchers liken the global loss of big trees to the tragedy that has already befallen the world's largest mammals, such as elephants, rhinos, tigers and whales, cautioning that almost nowhere do conservation programs have the time-frames lasting centuries, which are needed to assure the survival of old trees. They call for an urgent world-wide investigation to assess the extent of big tree loss, and to identify areas where big trees have a better chance of survival.
ScienceDailyDec. 6, 2012
New Landsat Imagery Sees Insect Outbreaks From Space
A new way of studying and visualizing Earth science data from a NASA and U.S. Geological Survey satellite
program is resulting in, for the first time, the ability to tease out the small events that can cause big changes in an ecosystem. Called LandTrendr, this computer program is able to find patterns previously buried within vast amounts of scientific data. Still in development, it has already led to seeing for the first time in satellite imagery an obscured, slow-moving decline and recovery of trees in Pacific Northwest forests. Comparing satellite data to ground data, scientists uncovered the cause to be insects. The unexpected disturbance pattern showed a long slow decline of tree health over years followed by slow regrowth. The data embedded in images are a scientific record of the Earth's surface that goes back 40 years. With the four-decade record, they can compare images between years and see how the land changes with time.
The ability to scroll backward and forward through time and a new technique for creating single visualizations out of millions of bits of data from hundreds of Landsat images has revealed not just the patchwork of fire scars and clear cuts but also the slow and subtle changes that take place over many years, including pulses of insect outbreaks.
Phys Org News January 15, 2013
Fungus Network Role in Plant Communication
Zdenka Babikova et. al.
Researchers devised an experiment to isolate the effects of mycorrhizae as a kind of information network among trees. The team concerned themselves with aphids, tiny insects that feed on and damage trees. The team grew sets of five trees, allowing three in each group to develop mycorrhizal networks, and preventing the mycorrhizae network growth in the other two. As the researchers allowed single trees in the sets to be infested with aphids, they found that if the infested tree was connected to another by the mycorrhizae, the un-infested tree began to mount its chemical defense. Those unconnected by the networks appeared not to receive the signal of attack and showed no chemical response.
The results clearly showed that trees can communicate the onset of an attack from aphids by making use of the underground network of mycorrhizae fungi. Researchers are also aware of instances of tree communication through the air, in which chemicals emitted by a damaged tree can be picked up by a neighbor.
The finding could be used in many crops that suffer aphid damage, by arranging for a particular, "sacrificial" plant to be more susceptible to aphid infestation, so that when aphids threaten, the network provides advance notice for the rest of the crop.
Ecology Letters MAY 9, 2013
Pollutants Rising Too Fast
Steven Mufson
Emissions of carbon dioxide from energy use rose 1.4% in 2012, setting a record and putting the planet on course for temperature increases well above the international climate goals. A report from the International Energy Agency said continuing that pace could mean a temperature increase over pre-industrial times of as much as 9°F(5° C). The energy sector accounts for more than two thirds of greenhouse gas emissions, so energy has a crucial role to play in tackling climate change. Aggressive energy-efficiency measures must
be carried out by 2015 to keep alive any hope of limiting climate change to 3.6°F(2° C).
The U.S. was one of the relatively bright spots in the report. U.S. emissions dropped 200 million tons, or 3.8%, in part due to a switch in power generation from coal to gas. U.S. emissions fell for the fourth time in the past five years, to a level last seen in the 1990's. Other factors in the U.S. decline were a mild winter, declining demand for gasoline and diesel fuels, and the increasing use of renewable energy.
Europe's emissions declined by 50 million tons, or 1.4%. But emissions rose 3.8% in China, the top carbon polluter. Yet that was one of the slowest increases in the past decade, and half of the 2011 rate increase. The level of carbon dioxide emissions per unit of electricity generation has fallen about 17% in China. However China remains the largest contributor of carbon dioxide into the atmosphere, with about a quarter of the global emissions.
Japan's emissions jumped 5.8% as it imported and burned large amounts of liquefied natural gas and coal to
compensate for the loss of nuclear plants idled since the tsunami damaged them and turned the population against the nuclear energy source. Emissions also climbed in developing countries outside the Organization of Economic Cooperation and Development, especially in the oil-rich Middle East, where fuel prices are
heavily subsidized.
Climate change is slipping down in the political agenda in many countries even though the scientific evidence about climate change continues to mount. The report mapped a way for countries and companies to contain increases in global temperatures. It urged them to implement energy-efficiency measures; limit the output of inefficient coal plants; mandate that all future coal plants be highly efficient; reduce the release of methane
in oil and gas operations; and phase out fossil-fuel subsidies.
Global climate talks are aimed at keeping the temperature rise below 3.6°F (2° C), compared with pre-industrial levels. The agency found that the world is on track for an increase of 6.5°F to 9.5°F (3.6° to 5.3°C), compared with pre-industrial levels. Climate negotiators meeting in Germany were haggling over a pact that is supposed to be adopted by 2015. The main sticking point is how to divide the burden between developed and developing countries. Industrialized countries want emerging economies such as China, India, and Brazil to take on bigger responsibilities. The report said developing countries account for 60% of emissions from energy, up from 45% in 2000.
Washington Post June 10, 2013
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 .5 CEUs for every 5 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. If you are also a Certified Forester, we will report your passing test scores to SAF for no additional cost. Tests with passing scores may be submitted only once to each organization.
Members of ISA may apply the .5 CEUs toward Certified Arborist or BCMA science credits.
Members of SAF can earn 0.5 hour Cat. 1-CT credits for every five passing test scores. SAF requires five passing test scores before reporting.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA and MTOA members may submit your ISA certification record to these organizations and receive credits one for one.
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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.
All test scores are sent to gibneyCE.com automatically when you press ‘next’ after taking the test and reviewing your answers. You will see a sending responses message after which you will be returned to our website. It is important to go through this process for your score to be recorded properly. All passing test scores are then 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 earned CEU credits on their website
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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 responses message.