Seminar #70 from Online Seminars for Municipal Arborists – September / October 2016
Sections Go directly to the section by clicking on the title below
Sections Go directly to the section by clicking on the title below
Note: Click on green text in each section for more information.
Trees in Rehabilitated Urban Soil
Edited by Len Phillips
During the change from rural to urban land uses, soils are degraded by compaction to facilitate building construction. The excellent soil for construction, but poor quality soil for trees, becomes a significant limiting factor for a city's tree survival and growth. The soil degradation includes vegetation and topsoil removal along with regrading and compaction to meet engineering standards for stable construction of buildings and infrastructure such as streets, sidewalks, and utilities. The soil is also altered by the removal of organic matter.
Municipal arborists have invented a lot of different ways to encourage the growth of tree roots in this terrible urban soil. One of these techniques is called soil rehabilitation.
Soil Rehabilitation
Soil rehabilitation is a newly refined technique designed to improve the quality of urban soil. While soil rehabilitation has the potential to improve soil quality in a limited area, the long-term effectiveness and consequences for tree growth is poorly documented. Soil rehabilitation has been refined and recently reported by Susan Day and her team at Virginia Tech. For the past several years, these researchers have been working on several alternative methods to developed a soil rehabilitation method that can help fix the compacted soils left behind after land development and building construction.
The objectives of this research was:
· to evaluate whether compaction can be reduced over the long-term in soil damaged by typical land development practices,
· to assess whether soil rehabilitation aids in new tree establishment,
· to quantify potential gains in tree growth and canopy cover resulting from soil rehabilitation.
With these objectives in mind, the team began growing trees in four different experimental soil treatments. They were:
Undisturbed Land – consisting of agricultural land with no pre-treatment. These plots were protected from traffic and trees were planted in the conventional method. There was no compacted soil to deal with and these trees were expected to grow very well.
Typical Practice – consisting of 4 inches (10 cm) of topsoil on the surface over compacted sub-soil. This treatment represents the typical practice employed by contractors to bring a building site to finished grade and prepare it for landscaping with the 4 inches of topsoil. These trees were not expected to do well.
Enhanced Topsoil – required improving the typical practice requiring the topsoil to be rototilled approximately 4 – 6 inches (12–15 cm) deep to eliminate the interface with compacted subgrade. Contractors sometimes employ this treatment to reduce the abrupt soil interface that can result when laying topsoil over a compacted subgrade. Because this tillage had only a temporary effect on tree growth, the tree roots can not grow deeper than the 4-6 inches soil that was tilled, so the trees are not expected to do well.
Soil Profile Rebuilding – this method used leaf compost and a backhoe with a tined bucket to physically break up the compacted soil and incorporate compost deep into the soil. In this procedure, the soil was lifted with the backhoe bucket to approximately 3 – 6 feet (1–2 m) and the soil was allowed to fall back to ground, serving to mix the two components and break up the soil clods. This process, called “subsoiling” was selected because the soil can be utilized in physically constrained urban sites. Efforts are required to clearly communicate to the equipment operator that this rebuilding method is to be applied to the entire soil area, not just where trees are to be planted. When the excavation is done and the compost is mixed in, four inches (12 cm) of topsoil is applied and rototilled to a depth of six to eight inches (15 to 20 cm), followed by planting the tree, which is expected to do very well.
Follow Up
The team evaluated growth, canopy development, and physiological response of several tree species over the first six years on the experimental soil treatments described above. The five tree species being evaluated were: red maple (Acer rubrum), swamp white oak (Quercus bicolor), bur oak (Quercus macocarpa), elm (Ulmus ‘Morton’ (Accolade), and cherry (Prunus ‘First Lady’).
After one year, the preliminary results showed that the soil profile rebuilding method was the clear winner of the four soil treatments, so the researchers decided to expand the soil profile rebuilding effort to locations along selected streets in Arlington. Virginia. The researchers planted three additional tree species in streetside plantings with and without soil profile rebuilding. The trees in this separate locations included: ginkgo (Ginkgo biloba), katsura (Cercidiphylum japonicum), and scarlet oak (Quercus coccinea).
Results
Soil profile rebuilding decreases soil compaction, encourages root growth, increases carbon sequestration, and increases the rate at which water moves through the soil, thereby improving storm-water capture. Using this method, trees grew more rapidly and soil depths immediately below the surface, 6 to 12 inches, (15–30 cm) had a reduced soil bulk density. The trunk cross-sectional area and canopy area of the trees in the soil profile rebuilding treatment matched or surpassed the trees planted in the undisturbed land. This method set the stage for long-term improvement of soil quality and improved the potential as a tool for stormwater mitigation. This method accelerates establishment and growth of urban trees planted in compacted urban soils indicating that the below-ground environment is a key component of this method. It is also a useful tool for designers seeking SITES® (Sustainable Sites Initiative) accreditation from the U.S. Green Building Council.
At the end of the study, the soil in each of the plots was analyzed for their physical and chemical characteristics. Samples were taken and measured for total carbon, aggregate stability, bulk density, and aggregate-associated carbon. Particle size distribution was analyzed from a representative of the range of soils included in the study. The trees were only very lightly pruned to enhance each tree's structure as needed.
The tree height and trunk diameter were measured with micro calipers in two perpendicular directions. Using the measurements, the trunk cross-sectional area was calculated. Canopy projection area was determined by measuring canopy spread in two perpendicular directions using the farthest reaching branch in each direction. Chlorophyll fluorescence and chlorophyll content index for all the species in this study were measured at regular intervals and at the same time as all the other measurements were taken.
Soil and Tree Characteristics
The soil pH at all the sites in this soil treatment experiment ranged from 5.1 to 5.8 except in soil profile rebuilding plots, which were slightly higher (6.3 – 7.1) presumably due to the addition of compost (pH 7.4). During the soil analysis, no compost was observed at soil depths below 14 inches (35 cm). The total soil organic carbon levels were not statistically different between the soil profile rebuilding plots and the control plots.
Tree survival was 100% with the exception of one red maple that was destroyed during a severe wind storm. After six growing seasons, trunk cross-sectional area had increased more rapidly in trees planted in the soil profile rebuilding plots for all species except Q. bicolor. Canopy projection area followed a similar pattern, although there was more variability and differences could not always be attributed to treatments. After one growing season, trees planted in soil profile rebuilding plots had a 77% greater average increase in cross-sectional area than the same species of trees in the control plots.
In the study, species considered slower to establish (Q. bicolor and Q. macrocarpa) did not begin to display treatment differences until after two or three growing seasons, while more rapidly establishing species began to demonstrate different growth rates after one growing season. Overall, soil profile rebuilding speeds growth and canopy development of planted trees which grew better, compared to conventional practices.
Source
· Layman, Rachel M., Susan D. Day, et.al., “Below ground matters: Urban soil rehabilitation increases tree canopy and speeds establishment”, Urban Forestry & Urban Greening, Volume 16, 2016.
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 Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
During the change from rural to urban land uses, soils are degraded by compaction to facilitate building construction. The excellent soil for construction, but poor quality soil for trees, becomes a significant limiting factor for a city's tree survival and growth. The soil degradation includes vegetation and topsoil removal along with regrading and compaction to meet engineering standards for stable construction of buildings and infrastructure such as streets, sidewalks, and utilities. The soil is also altered by the removal of organic matter.
Municipal arborists have invented a lot of different ways to encourage the growth of tree roots in this terrible urban soil. One of these techniques is called soil rehabilitation.
Soil Rehabilitation
Soil rehabilitation is a newly refined technique designed to improve the quality of urban soil. While soil rehabilitation has the potential to improve soil quality in a limited area, the long-term effectiveness and consequences for tree growth is poorly documented. Soil rehabilitation has been refined and recently reported by Susan Day and her team at Virginia Tech. For the past several years, these researchers have been working on several alternative methods to developed a soil rehabilitation method that can help fix the compacted soils left behind after land development and building construction.
The objectives of this research was:
· to evaluate whether compaction can be reduced over the long-term in soil damaged by typical land development practices,
· to assess whether soil rehabilitation aids in new tree establishment,
· to quantify potential gains in tree growth and canopy cover resulting from soil rehabilitation.
With these objectives in mind, the team began growing trees in four different experimental soil treatments. They were:
Undisturbed Land – consisting of agricultural land with no pre-treatment. These plots were protected from traffic and trees were planted in the conventional method. There was no compacted soil to deal with and these trees were expected to grow very well.
Typical Practice – consisting of 4 inches (10 cm) of topsoil on the surface over compacted sub-soil. This treatment represents the typical practice employed by contractors to bring a building site to finished grade and prepare it for landscaping with the 4 inches of topsoil. These trees were not expected to do well.
Enhanced Topsoil – required improving the typical practice requiring the topsoil to be rototilled approximately 4 – 6 inches (12–15 cm) deep to eliminate the interface with compacted subgrade. Contractors sometimes employ this treatment to reduce the abrupt soil interface that can result when laying topsoil over a compacted subgrade. Because this tillage had only a temporary effect on tree growth, the tree roots can not grow deeper than the 4-6 inches soil that was tilled, so the trees are not expected to do well.
Soil Profile Rebuilding – this method used leaf compost and a backhoe with a tined bucket to physically break up the compacted soil and incorporate compost deep into the soil. In this procedure, the soil was lifted with the backhoe bucket to approximately 3 – 6 feet (1–2 m) and the soil was allowed to fall back to ground, serving to mix the two components and break up the soil clods. This process, called “subsoiling” was selected because the soil can be utilized in physically constrained urban sites. Efforts are required to clearly communicate to the equipment operator that this rebuilding method is to be applied to the entire soil area, not just where trees are to be planted. When the excavation is done and the compost is mixed in, four inches (12 cm) of topsoil is applied and rototilled to a depth of six to eight inches (15 to 20 cm), followed by planting the tree, which is expected to do very well.
Follow Up
The team evaluated growth, canopy development, and physiological response of several tree species over the first six years on the experimental soil treatments described above. The five tree species being evaluated were: red maple (Acer rubrum), swamp white oak (Quercus bicolor), bur oak (Quercus macocarpa), elm (Ulmus ‘Morton’ (Accolade), and cherry (Prunus ‘First Lady’).
After one year, the preliminary results showed that the soil profile rebuilding method was the clear winner of the four soil treatments, so the researchers decided to expand the soil profile rebuilding effort to locations along selected streets in Arlington. Virginia. The researchers planted three additional tree species in streetside plantings with and without soil profile rebuilding. The trees in this separate locations included: ginkgo (Ginkgo biloba), katsura (Cercidiphylum japonicum), and scarlet oak (Quercus coccinea).
Results
Soil profile rebuilding decreases soil compaction, encourages root growth, increases carbon sequestration, and increases the rate at which water moves through the soil, thereby improving storm-water capture. Using this method, trees grew more rapidly and soil depths immediately below the surface, 6 to 12 inches, (15–30 cm) had a reduced soil bulk density. The trunk cross-sectional area and canopy area of the trees in the soil profile rebuilding treatment matched or surpassed the trees planted in the undisturbed land. This method set the stage for long-term improvement of soil quality and improved the potential as a tool for stormwater mitigation. This method accelerates establishment and growth of urban trees planted in compacted urban soils indicating that the below-ground environment is a key component of this method. It is also a useful tool for designers seeking SITES® (Sustainable Sites Initiative) accreditation from the U.S. Green Building Council.
At the end of the study, the soil in each of the plots was analyzed for their physical and chemical characteristics. Samples were taken and measured for total carbon, aggregate stability, bulk density, and aggregate-associated carbon. Particle size distribution was analyzed from a representative of the range of soils included in the study. The trees were only very lightly pruned to enhance each tree's structure as needed.
The tree height and trunk diameter were measured with micro calipers in two perpendicular directions. Using the measurements, the trunk cross-sectional area was calculated. Canopy projection area was determined by measuring canopy spread in two perpendicular directions using the farthest reaching branch in each direction. Chlorophyll fluorescence and chlorophyll content index for all the species in this study were measured at regular intervals and at the same time as all the other measurements were taken.
Soil and Tree Characteristics
The soil pH at all the sites in this soil treatment experiment ranged from 5.1 to 5.8 except in soil profile rebuilding plots, which were slightly higher (6.3 – 7.1) presumably due to the addition of compost (pH 7.4). During the soil analysis, no compost was observed at soil depths below 14 inches (35 cm). The total soil organic carbon levels were not statistically different between the soil profile rebuilding plots and the control plots.
Tree survival was 100% with the exception of one red maple that was destroyed during a severe wind storm. After six growing seasons, trunk cross-sectional area had increased more rapidly in trees planted in the soil profile rebuilding plots for all species except Q. bicolor. Canopy projection area followed a similar pattern, although there was more variability and differences could not always be attributed to treatments. After one growing season, trees planted in soil profile rebuilding plots had a 77% greater average increase in cross-sectional area than the same species of trees in the control plots.
In the study, species considered slower to establish (Q. bicolor and Q. macrocarpa) did not begin to display treatment differences until after two or three growing seasons, while more rapidly establishing species began to demonstrate different growth rates after one growing season. Overall, soil profile rebuilding speeds growth and canopy development of planted trees which grew better, compared to conventional practices.
Source
· Layman, Rachel M., Susan D. Day, et.al., “Below ground matters: Urban soil rehabilitation increases tree canopy and speeds establishment”, Urban Forestry & Urban Greening, Volume 16, 2016.
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 Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Staking New Trees
By Len Phillips
In the last Seminar, research was presented that described nine types of new, commercially available tree staking systems. The conclusion was that above ground guying, while very common, can cause additional stress and the potential failure of the tree. Instead, a strong consideration must be given to installing below grade stabilization systems that anchor the root ball firmly to the soil, and are the better option for the tree's recovery from the transplanting process. Below-grade stabilization meets the safety, aesthetics, and “what’s best for the tree” concerns.
In the previous Seminar, the following below ground methods were discussed: 2 x 2, the dowels, Terra Toggle, and the Tree Staple. What follows are four other, commercially available options, that meet the requirement of anchoring the ball firmly to the soil at the bottom of the planting pit.
UPI Manufacturing Tree Stabilizer Kits
UPI Manufacturing produces Tree Stabilizer Kits that come packaged with all the components necessary to stabilize a newly planted tree, below grade. These kits stabilize the root ball, while allowing movement to the canopy. These kits fit any caliper tree and come with instructions and three 1½ in x 20 in (4x50 cm) perforated tubes. The kit also includes 3 – two-year – time release fertilizer tablets, a 6 feet (2 meters) long harness strap, as well as cam buckles and hooks that are used to connect the harness to the tubes.
The perforated tubes are installed by inserting a steel stake inside each tube and driving the stake and tube 20 inches (50 cm) into the ground, just beyond the root ball. Then the steel stake is removed, leaving the tube in the ground, the process is repeated until all three tubes are in the ground, equal distance around the root ball. When the tubes are in the ground, the tree is planted and the harness straps are installed between the tubes and over the root system.
The tubes provide a way for water, the fertilizer tablets, and oxygen to penetrate the top 20” of soil around the tree’s roots for the life of the kit. Once established (or after 8 to 12 months), the harness straps may be removed for use elsewhere, while the tubes remain in the ground and continue to provide a simple way to provide water, oxygen, and the dissolved fertilizer to the roots for years to come. This product installation requires two people at least ten minutes to install.
Root Anchor™ Tree Staking
The Root Anchor™ underground tree stakes are manufactured by Tree Stake Solutions. The Root Anchor™ is a tree root stabilizing system that involves centering a “cage” (or open metal ring) over the surface of the root ball, after the tree is planted.
The three, flat-topped stakes are driven outside the root ball and through the cage, deep into undisturbed earth below the root ball. The flat-topped stakes hold the cage tight to the root ball top and the solid bottom of the planting hole. The stable root ball allows young roots to develop in a suitable environment, while holding the transplanted tree upright during high winds. This product can be installed in the time it takes to lay the cage over the root ball and drive the tree stakes into the ground.
The system is intended to remain for as long as it takes for the metal cage to decompose, although it may be removed when the tree is established or a year after planting. Removing the cage will prevent long term problems, such as if the tree dies and a stump grinder might become damaged by the buried metal.
Duckbill® Anchors
Duckbill anchors are manufactured by Foresight Products and can be used with all types of guy systems, but the company has developed a “Root Ball Kit” that is specifically designed to hold the tree’s root ball firmly in planting hole.
The kit is based on driving three duckbill anchors below the root ball hole. The anchors are attached by cables that terminate in eyelets, and are driven into the ground via a steel rod and hammer. Once anchored, the rod is removed and the cable pulled to set the duckbill firmly in the soil. The tree is then planted in the hole. Next, a strap is run through the first eyelet, over the root ball to the next eyelet and after that, to the third eyelet and back toward the first. The strap is pulled snug between the first and third eyelet. Finally, the ratchet supplied in the kit is used to tighten the strap and firmly secure the root ball to the soil.
The manufacturer says it is an effective, lightweight and economical anchoring application for large or small trees. This product takes two people several minutes to drive the 3 long stakes and duckbills into the ground and install the strap through the three eyelets around the tree. There is no recommendation regarding removal of this system after the tree is established.
Tomahawk Tree Stabilization
The Tomahawk Tree Stabilization system is manufactured by Border Concepts Inc. This system is similar to the Tree Staple, except the horizontal bar extends beyond the prongs and the prongs are hollow to permit watering and fertilizing through the metal tube. The horizontal bars are notched for extra guying in extremely windy sites. Observing a video of the installation, it appears that driving the prongs into the root ball, requires 2 minutes with a sledge hammer. Removing the Tomahawk system after the tree roots have begun to grow, or 6 months, is optional.
Review
When making a decision as to which option to use, here is a review of the below grade stabilization options presented in the last Seminar.
2 x 2 Staple
The first system was called 2 x 2 Staple because it was made from 2 x 2 lumber with one long piece crossing over the root ball and screwed or nailed to two shorter pieces driven into solid ground on either side of the root ball. They look like wood staple and a pair of these staples is driven into either side of the tree trunk. There is no need to remove this home-made system after the tree is established. See Photo
Dowels
The dowel system consists of three long wooden dowels or re-bar driven through the root ball. The wood dowels will decompose in a couple of years, but the re-bars, should probably be removed if there is a chance the tree might die and the stump might be removed by grinding.
Terra Toggle™
The Terra Toggle™ consists of polypropylene strapping holding a piece of lumber and the root ball firmly to the ground with anchors. This system is similar to the 2 x 2 and is installed after the tree is set in the planting pit but before any backfill is added to the hole. This system does not need to be removed after the tree becomes established.
Tree Staple™
The Tree Staple™ consists of a long metal prong that provides vertical support and serves as an anchor to the firm soil below the root ball. The shorter prong restricts twisting of the root ball movement and firmly locks the root ball in-place. The cross member stretches across a portion of the root ball, applying downward pressure. One person using a sledge hammer can install this system in about a minute.
Conclusion
All of these options secure new plantings by the root-ball that provides notable cost savings through quick and easy installation and the optional need for removal. The only disadvantage is that if the tree dies and the stump needs to be removed, any metal from the stabilizing system should be removed prior to the stump grinding.
Sources:
- Focus Section, “Tree Staking Options”, Landscape Architect and Specifier News, April 2015.
- UPI Manufacturing website
- Root Anchor™ website
- Duckbill® website
- Tomahawk Tree Stabilization website
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .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 practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Len Phillips
In the last Seminar, research was presented that described nine types of new, commercially available tree staking systems. The conclusion was that above ground guying, while very common, can cause additional stress and the potential failure of the tree. Instead, a strong consideration must be given to installing below grade stabilization systems that anchor the root ball firmly to the soil, and are the better option for the tree's recovery from the transplanting process. Below-grade stabilization meets the safety, aesthetics, and “what’s best for the tree” concerns.
In the previous Seminar, the following below ground methods were discussed: 2 x 2, the dowels, Terra Toggle, and the Tree Staple. What follows are four other, commercially available options, that meet the requirement of anchoring the ball firmly to the soil at the bottom of the planting pit.
UPI Manufacturing Tree Stabilizer Kits
UPI Manufacturing produces Tree Stabilizer Kits that come packaged with all the components necessary to stabilize a newly planted tree, below grade. These kits stabilize the root ball, while allowing movement to the canopy. These kits fit any caliper tree and come with instructions and three 1½ in x 20 in (4x50 cm) perforated tubes. The kit also includes 3 – two-year – time release fertilizer tablets, a 6 feet (2 meters) long harness strap, as well as cam buckles and hooks that are used to connect the harness to the tubes.
The perforated tubes are installed by inserting a steel stake inside each tube and driving the stake and tube 20 inches (50 cm) into the ground, just beyond the root ball. Then the steel stake is removed, leaving the tube in the ground, the process is repeated until all three tubes are in the ground, equal distance around the root ball. When the tubes are in the ground, the tree is planted and the harness straps are installed between the tubes and over the root system.
The tubes provide a way for water, the fertilizer tablets, and oxygen to penetrate the top 20” of soil around the tree’s roots for the life of the kit. Once established (or after 8 to 12 months), the harness straps may be removed for use elsewhere, while the tubes remain in the ground and continue to provide a simple way to provide water, oxygen, and the dissolved fertilizer to the roots for years to come. This product installation requires two people at least ten minutes to install.
Root Anchor™ Tree Staking
The Root Anchor™ underground tree stakes are manufactured by Tree Stake Solutions. The Root Anchor™ is a tree root stabilizing system that involves centering a “cage” (or open metal ring) over the surface of the root ball, after the tree is planted.
The three, flat-topped stakes are driven outside the root ball and through the cage, deep into undisturbed earth below the root ball. The flat-topped stakes hold the cage tight to the root ball top and the solid bottom of the planting hole. The stable root ball allows young roots to develop in a suitable environment, while holding the transplanted tree upright during high winds. This product can be installed in the time it takes to lay the cage over the root ball and drive the tree stakes into the ground.
The system is intended to remain for as long as it takes for the metal cage to decompose, although it may be removed when the tree is established or a year after planting. Removing the cage will prevent long term problems, such as if the tree dies and a stump grinder might become damaged by the buried metal.
Duckbill® Anchors
Duckbill anchors are manufactured by Foresight Products and can be used with all types of guy systems, but the company has developed a “Root Ball Kit” that is specifically designed to hold the tree’s root ball firmly in planting hole.
The kit is based on driving three duckbill anchors below the root ball hole. The anchors are attached by cables that terminate in eyelets, and are driven into the ground via a steel rod and hammer. Once anchored, the rod is removed and the cable pulled to set the duckbill firmly in the soil. The tree is then planted in the hole. Next, a strap is run through the first eyelet, over the root ball to the next eyelet and after that, to the third eyelet and back toward the first. The strap is pulled snug between the first and third eyelet. Finally, the ratchet supplied in the kit is used to tighten the strap and firmly secure the root ball to the soil.
The manufacturer says it is an effective, lightweight and economical anchoring application for large or small trees. This product takes two people several minutes to drive the 3 long stakes and duckbills into the ground and install the strap through the three eyelets around the tree. There is no recommendation regarding removal of this system after the tree is established.
Tomahawk Tree Stabilization
The Tomahawk Tree Stabilization system is manufactured by Border Concepts Inc. This system is similar to the Tree Staple, except the horizontal bar extends beyond the prongs and the prongs are hollow to permit watering and fertilizing through the metal tube. The horizontal bars are notched for extra guying in extremely windy sites. Observing a video of the installation, it appears that driving the prongs into the root ball, requires 2 minutes with a sledge hammer. Removing the Tomahawk system after the tree roots have begun to grow, or 6 months, is optional.
Review
When making a decision as to which option to use, here is a review of the below grade stabilization options presented in the last Seminar.
2 x 2 Staple
The first system was called 2 x 2 Staple because it was made from 2 x 2 lumber with one long piece crossing over the root ball and screwed or nailed to two shorter pieces driven into solid ground on either side of the root ball. They look like wood staple and a pair of these staples is driven into either side of the tree trunk. There is no need to remove this home-made system after the tree is established. See Photo
Dowels
The dowel system consists of three long wooden dowels or re-bar driven through the root ball. The wood dowels will decompose in a couple of years, but the re-bars, should probably be removed if there is a chance the tree might die and the stump might be removed by grinding.
Terra Toggle™
The Terra Toggle™ consists of polypropylene strapping holding a piece of lumber and the root ball firmly to the ground with anchors. This system is similar to the 2 x 2 and is installed after the tree is set in the planting pit but before any backfill is added to the hole. This system does not need to be removed after the tree becomes established.
Tree Staple™
The Tree Staple™ consists of a long metal prong that provides vertical support and serves as an anchor to the firm soil below the root ball. The shorter prong restricts twisting of the root ball movement and firmly locks the root ball in-place. The cross member stretches across a portion of the root ball, applying downward pressure. One person using a sledge hammer can install this system in about a minute.
Conclusion
All of these options secure new plantings by the root-ball that provides notable cost savings through quick and easy installation and the optional need for removal. The only disadvantage is that if the tree dies and the stump needs to be removed, any metal from the stabilizing system should be removed prior to the stump grinding.
Sources:
- Focus Section, “Tree Staking Options”, Landscape Architect and Specifier News, April 2015.
- UPI Manufacturing website
- Root Anchor™ website
- Duckbill® website
- Tomahawk Tree Stabilization website
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .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 practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Tree of the Seminar #70
By Len Phillips
A vigorous small tree with upright branching, MaacNificent® Maackia forms a beautiful, symmetrical vase shaped specimen. Spike-like racemes of white flowers decorate the tree in early summer. The green foliage shows silvery pubescence in spring.
Trade Name: MaacNificent® Maackia
Botanical Name: Maackia amurensis ‘JFS-Schichtel1’
Family: Fabaceae
Parentage: A native of Manchuria, introduced in 1864; this cultivar was released in 2012
Height: 30'
Spread: 20' – 30'
Form: Upright branching, forming a vase-shaped crown
Flower: White in early summer, upright racemes of pea-like flowers smell like mowed grass
Fruit: A flat pod, 2 to 3’’ long, 1/3’’ wide
Foliage: Alternate, compound, leaflets are arranged opposite on the stem and 2-3½’’ long
Spring Color: Pale yellowish-green stems and young leaves
Summer Foliage: Green with silvery tint
Autumn Foliage: Leaves turn yellow in the fall
Winter Color: Handsome bark and form in winter
Bark: Peeling with maturity, rich shinny brown
Habitat: Grows well just about everywhere
Culture: Performs best in well-drained soils, will not tolerate extreme acid or alkaline conditions.
Hardiness Zone: 3 – 8
Growth Rate: Slow growing, but faster than the species
Pest Resistance: Free of major pest problems
Storm Resistance: Good
Salt Resistance: Good
Planting: Easy to transplant bare root, B&B, or container
Pruning: Prune for structure two years after planting Propagating: Cuttings or buds grafted to seedling rootstock
Design Uses: Excellent for smaller locations
Companions: Best in a perennial garden
Site Requirements: Full sun to partial shade
Other Comments: A member of the pea family, it is able to fix its own nitrogen to assist in its growth.
Photo
Sources
This information has been gathered from personal observations of the author, living in Massachusetts, Zone 6 and information provided by 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, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Len Phillips
A vigorous small tree with upright branching, MaacNificent® Maackia forms a beautiful, symmetrical vase shaped specimen. Spike-like racemes of white flowers decorate the tree in early summer. The green foliage shows silvery pubescence in spring.
Trade Name: MaacNificent® Maackia
Botanical Name: Maackia amurensis ‘JFS-Schichtel1’
Family: Fabaceae
Parentage: A native of Manchuria, introduced in 1864; this cultivar was released in 2012
Height: 30'
Spread: 20' – 30'
Form: Upright branching, forming a vase-shaped crown
Flower: White in early summer, upright racemes of pea-like flowers smell like mowed grass
Fruit: A flat pod, 2 to 3’’ long, 1/3’’ wide
Foliage: Alternate, compound, leaflets are arranged opposite on the stem and 2-3½’’ long
Spring Color: Pale yellowish-green stems and young leaves
Summer Foliage: Green with silvery tint
Autumn Foliage: Leaves turn yellow in the fall
Winter Color: Handsome bark and form in winter
Bark: Peeling with maturity, rich shinny brown
Habitat: Grows well just about everywhere
Culture: Performs best in well-drained soils, will not tolerate extreme acid or alkaline conditions.
Hardiness Zone: 3 – 8
Growth Rate: Slow growing, but faster than the species
Pest Resistance: Free of major pest problems
Storm Resistance: Good
Salt Resistance: Good
Planting: Easy to transplant bare root, B&B, or container
Pruning: Prune for structure two years after planting Propagating: Cuttings or buds grafted to seedling rootstock
Design Uses: Excellent for smaller locations
Companions: Best in a perennial garden
Site Requirements: Full sun to partial shade
Other Comments: A member of the pea family, it is able to fix its own nitrogen to assist in its growth.
Photo
Sources
This information has been gathered from personal observations of the author, living in Massachusetts, Zone 6 and information provided by 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, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Squirrel Damage to Trees
by Steve Gardner
Squirrel's have been seen stripping the bark off a tree that could possibly cause tree death. A secondary issue of importance are the pathogens that may be active in the area and invade the tree. Typically the damage occurs in the spring during squirrel nest construction period and in the fall during the gathering of nuts and seeds.
Damage to Tree Bark
Fox squirrels (Sciurus niger), gray squirrels (Sciurus carolinensis), tassel-eared squirrels (Sciurus aberti) and red squirrels (Tamiasciurus hudsonicus) may cause damage to tree bark that can be quite severe. Fox squirrels exist in the middle portion of the continental U.S.; gray squirrels exist in the Eastern portion of the U.S.; and red squirrels are found all over the U.S. Tassel-eared squirrels are found in the Rocky Mountain region.
Types of Trees Stripped
Deciduous trees with smooth bark sustain the most damage, but other trees can be targeted. Red squirrels like to clip branches off maples (particularly sugar maples) to get at the sweet sap. Other squirrel-damaged trees include: Atlas cedar (Cedrus), other maples (Acer), ash (Fraxinus), autumn olives (Elaeagnus), baldcypress (Taxodium), willow (Salix), elm (Ulmus), ginkgo (Ginkgo), hackberry (Celtis), honeysuckle (Lonicera), honeylocust (Gleditsia), lilac (Syringa), little-leaf linden (Tilia cordata), mulberry tree (Morus), oak (Quercus), pecan (Carya), pines (Pinus), poplar (Populus), tulip poplar (Liriodendron), redwood (Sequoia), Russian olive (Elaeagnus), and sycamore (Platanus).
Identification of Bark Stripping
Typically, bark strips are ½ inch (1.2 cm) wide and 3 – 6 inches (7-15 cm) long. Other small limbs and branches of 1 – 2 feet (30-60 cm) in length and ¼ – ½ inch (0.6-1.2 cm) diameter, are clipped and dropped to the ground. Squirrels prefer to strip branches that are horizontal, but they have been known to strip trunks as well. The damage can be extensive. Bark stripping usually occurs in late winter through to spring.
Why Squirrels Strip Bark
There are several theories:
· Pregnant females often do not eat just prior to giving birth. Researchers think the bark stripping may be the female's way of responding to a pain of hunger or birthing.
· Squirrels are searching for certain nutrients found by eating the inner bark layer.
· Squirrels may strip bark simply because they enjoy doing it.
· Occasionally, squirrels will gnaw on structures, decks, porches, fences, and other objects that do not provide nutrition, moisture, or housing needs. It is believed that this type of damage is a byproduct of territorial marking.
· Tassel-eared squirrels use the twigs to feed on the nutrients found in the cambium layers of pine and firs.
Prevent Bark Stripping
Squirrels typically strip bark during winter and spring. Twig clipping occurs most frequently in spring and early fall. Fortunately, trees can sustain the loss of bark from up to 50% of the trunk’s circumference and foliage losses of up to 30% without significant impacts.
Landowners can prevent damage to trees by installing metal collars around the tree trunk. If a physical barrier, such as metal flashing is not an option, then commercial repellents can be effective. Petroleum-based repellents can also help discourage squirrel access to trees and branches. However, this repellent requires protection to the tree from a petroleum-based repellent. This can be accomplished by applying a plastic barrier between the tree surface and the repellent as described on the label instructions. Repeat as necessary. If the impact to trees or structures is significant, consider removing the offending squirrels by cage, trapping, or shooting, where permitted by local ordinance.
Habitat Modification
With isolated trees or groups of trees, wrap tree trunks with 24 inches (60 cm) (or greater) aluminum flashing at least 6 feet (2 m) off ground to prevent the squirrel from climbing the tree. Place ¼ inch (0.6 cm) wedge between tree and flashing to prevent mold development. Another option is wrapping 3 rows of porcupine wire spaced with tines 2 inches (5 cm) apart around the trunk to prevent the squirrel from climbing up the tree. Be sure the porcupine wire is at least 8 feet (2½ m) off the ground to prevent people from accidentally becoming impaled. Another option is to remove or modify all bird feeders nearby.
Repellents
Taste repellents can be effective to stop squirrel gnawing on a particular spot. Read the label to be sure the tree will not be harmed. This option has limited value and must be reapplied after rain storms.
Repair Bark Stripping
If an area of bark is stripped off a tree by a squirrel or by any other means and the wound is very fresh, try to staple the bark back in place or tie in place with string being careful not to further damage the cambial or living tissues. Then cover all the seams with grafting wax. This often works to restore the bark, but timing is critical.
If the bark has dried out and the wound is more than a couple of hours old, use a very shape knife to cut the bark back to where it is attached to the wood below and leave it alone. If the tree is otherwise healthy, it will begin healing itself by producing callus tissue that will roll over the open, stripped area in the next few years. Trees have better defensive mechanisms than most people realize. The wound should not be treated with paint, emulsions, or wound dressings because these coatings trap moisture against the bark and wood, encouraging decay.
Historically, it was sometimes recommended to scribe a wound on a tree or cut the bark around the wound to achieve an elliptical shape, but this is no longer recommended and it is better to minimize the amount of healthy tissue removed.
Sources
· American Tree Service Supply blog posted by Steve Gardner on March 15, 2014.
· Internet Center for Wildlife Damage Management, “Squirrel Damage Management”, University of Nebraska-Lincoln, 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, or BCMA practice 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 Steve Gardner
Squirrel's have been seen stripping the bark off a tree that could possibly cause tree death. A secondary issue of importance are the pathogens that may be active in the area and invade the tree. Typically the damage occurs in the spring during squirrel nest construction period and in the fall during the gathering of nuts and seeds.
Damage to Tree Bark
Fox squirrels (Sciurus niger), gray squirrels (Sciurus carolinensis), tassel-eared squirrels (Sciurus aberti) and red squirrels (Tamiasciurus hudsonicus) may cause damage to tree bark that can be quite severe. Fox squirrels exist in the middle portion of the continental U.S.; gray squirrels exist in the Eastern portion of the U.S.; and red squirrels are found all over the U.S. Tassel-eared squirrels are found in the Rocky Mountain region.
Types of Trees Stripped
Deciduous trees with smooth bark sustain the most damage, but other trees can be targeted. Red squirrels like to clip branches off maples (particularly sugar maples) to get at the sweet sap. Other squirrel-damaged trees include: Atlas cedar (Cedrus), other maples (Acer), ash (Fraxinus), autumn olives (Elaeagnus), baldcypress (Taxodium), willow (Salix), elm (Ulmus), ginkgo (Ginkgo), hackberry (Celtis), honeysuckle (Lonicera), honeylocust (Gleditsia), lilac (Syringa), little-leaf linden (Tilia cordata), mulberry tree (Morus), oak (Quercus), pecan (Carya), pines (Pinus), poplar (Populus), tulip poplar (Liriodendron), redwood (Sequoia), Russian olive (Elaeagnus), and sycamore (Platanus).
Identification of Bark Stripping
Typically, bark strips are ½ inch (1.2 cm) wide and 3 – 6 inches (7-15 cm) long. Other small limbs and branches of 1 – 2 feet (30-60 cm) in length and ¼ – ½ inch (0.6-1.2 cm) diameter, are clipped and dropped to the ground. Squirrels prefer to strip branches that are horizontal, but they have been known to strip trunks as well. The damage can be extensive. Bark stripping usually occurs in late winter through to spring.
Why Squirrels Strip Bark
There are several theories:
· Pregnant females often do not eat just prior to giving birth. Researchers think the bark stripping may be the female's way of responding to a pain of hunger or birthing.
· Squirrels are searching for certain nutrients found by eating the inner bark layer.
· Squirrels may strip bark simply because they enjoy doing it.
· Occasionally, squirrels will gnaw on structures, decks, porches, fences, and other objects that do not provide nutrition, moisture, or housing needs. It is believed that this type of damage is a byproduct of territorial marking.
· Tassel-eared squirrels use the twigs to feed on the nutrients found in the cambium layers of pine and firs.
Prevent Bark Stripping
Squirrels typically strip bark during winter and spring. Twig clipping occurs most frequently in spring and early fall. Fortunately, trees can sustain the loss of bark from up to 50% of the trunk’s circumference and foliage losses of up to 30% without significant impacts.
Landowners can prevent damage to trees by installing metal collars around the tree trunk. If a physical barrier, such as metal flashing is not an option, then commercial repellents can be effective. Petroleum-based repellents can also help discourage squirrel access to trees and branches. However, this repellent requires protection to the tree from a petroleum-based repellent. This can be accomplished by applying a plastic barrier between the tree surface and the repellent as described on the label instructions. Repeat as necessary. If the impact to trees or structures is significant, consider removing the offending squirrels by cage, trapping, or shooting, where permitted by local ordinance.
Habitat Modification
With isolated trees or groups of trees, wrap tree trunks with 24 inches (60 cm) (or greater) aluminum flashing at least 6 feet (2 m) off ground to prevent the squirrel from climbing the tree. Place ¼ inch (0.6 cm) wedge between tree and flashing to prevent mold development. Another option is wrapping 3 rows of porcupine wire spaced with tines 2 inches (5 cm) apart around the trunk to prevent the squirrel from climbing up the tree. Be sure the porcupine wire is at least 8 feet (2½ m) off the ground to prevent people from accidentally becoming impaled. Another option is to remove or modify all bird feeders nearby.
Repellents
Taste repellents can be effective to stop squirrel gnawing on a particular spot. Read the label to be sure the tree will not be harmed. This option has limited value and must be reapplied after rain storms.
Repair Bark Stripping
If an area of bark is stripped off a tree by a squirrel or by any other means and the wound is very fresh, try to staple the bark back in place or tie in place with string being careful not to further damage the cambial or living tissues. Then cover all the seams with grafting wax. This often works to restore the bark, but timing is critical.
If the bark has dried out and the wound is more than a couple of hours old, use a very shape knife to cut the bark back to where it is attached to the wood below and leave it alone. If the tree is otherwise healthy, it will begin healing itself by producing callus tissue that will roll over the open, stripped area in the next few years. Trees have better defensive mechanisms than most people realize. The wound should not be treated with paint, emulsions, or wound dressings because these coatings trap moisture against the bark and wood, encouraging decay.
Historically, it was sometimes recommended to scribe a wound on a tree or cut the bark around the wound to achieve an elliptical shape, but this is no longer recommended and it is better to minimize the amount of healthy tissue removed.
Sources
· American Tree Service Supply blog posted by Steve Gardner on March 15, 2014.
· Internet Center for Wildlife Damage Management, “Squirrel Damage Management”, University of Nebraska-Lincoln, 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, or BCMA practice 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.
Mycorrhizal Inoculants – Useful or Useless?
By Peter Thurman and Len Phillips
In the natural environment, mycorrhizal fungi are found associated with the roots of most woody plants. They are a group of fungi that live in a symbiotic or mutually beneficial relationship with plants, by wrapping around or penetrating plant roots and then proliferating through the soil beyond the host plant’s roots - effectively extending the root system volume of the host plant's roots by hundreds of times. These fungi release enzymes which help break down nutrients into forms more easily utilized by the plant. Many researchers and arborists consider that, while this group of fungi is very important, maybe even vital, in natural conditions, there is a significant risk that they are often depleted by cultivation, chemical use, compaction, and topsoil erosion.
The Positives
Think of mycorrhizal fungi as a vast network of very fine tree roots. Although not plant roots, they behave in ways similar to them. They burrow into nooks and crannies between soil particles and collect water and nutrients for their hosts. In return, the photosynthetic process of the host trees send sugars to the fungi as food.
The uniqueness of mycorrhizal fungi lies in their ability to readily absorb elements such as phosphates, manganese, copper, and zinc dissolved in water, for use by a plant. Mycorrhizal fungi form when some fungi infect young, emerging non-woody roots. They do this in several different ways. They expand the absorbing surface as the hyphae reach out and as they grow into the soil. They also have chitin in their boundaries which is very adept at absorbing large molecules such as the phosphate molecule.
Natural phosphate in the soil and applied phosphate fertilizer particles are tightly bound to the soil particles, making it unavailable to trees. A small percentage of bound phosphate will gradually be converted into available forms, but this does not happen quickly or efficiently. At least 25% of the phosphate in soils never becomes available, making it crucial to get the most efficient use of fertilizer phosphate. Mycorrhizal fungi inoculants help to release some of the phosphate making it more available for the host plant to use.
Given this important symbiotic association, it is natural to think that it would be beneficial to add more mycorrhizal fungi to the soil.
One positive note is that once mycorrhizal fungi have attached to the rhizosphere, it stays and grows with the host as long as conditions remain suitable. However, some researchers have found that you must inoculate the plant's roots with mycorrhizal fungi. You cannot inoculate the soil with these fungi.
Nurseries will sometimes add mycorrhizal fungi to the soil around their trees and use this fact as part of their marketing strategy. Such products give 'added-value' when their product is sold, but its effectiveness is not proven.
The Problems
We can now buy mycorrhizal fungi inoculants in packets when we purchase a tree, shrub or rose bush. Many of the mycorrhizal fungi inoculant mixes are sold as very host-specific but this may not be true because the inoculant usually consists of only 2 or 3 types of fungi. It turns out that there are hundreds if not thousands of different kinds of mycorrhizal fungi in the soil where a tree may be planted and some of these mycorrhizal fungi are very specific to certain types of plants especially when it comes to trees. The manufacturer hopes that, with a large number of spores, maybe some will be responsive. Conversely, other products are sold as a do-all, fix-all cocktail, suggesting that it is suitable for a very wide range of species, but in essence, may not be true.
There is no doubt that mycorrhizae are very important, if not vital, to plants growing in the natural environment but can they be successfully ‘dropped in’ to man-made landscapes? The trouble is, we don’t know. Do they, will they ‘work’ in such scenarios – whatever the mix being offered?
Put simply, inoculants are commercial products that lack scientific trials and proof of effectiveness. There are thousands of scientific papers on mycorrhizae and commercial inoculants but most have been written by people with a vested interest in the product – such as scientists who work for the commercial manufacturer.
Furthermore, we, the authors, have failed to find any papers on successful, well-designed trials that have been peer reviewed and replicated by independent scholars or organizations that would not benefit financially from positive results. The results of one paper by independent researchers (Ferrini & Fini 2011) were only marginally positive and certainly not convincing enough to support the use of mycorrhizal inoculants.
It is very difficult to determine if an inoculant is of high quality. Some manufacturers count 'propagules' instead of 'spores.' Propagules can include root fragments and other inert materials, so the spore count might actually be much lower. Furthermore, these very specific species almost certainly are from an area that is foreign to the soil where a tree is to be planted. It is even possible that these foreign species will inhibit the growth of the native species but there is often no way of knowing the mycorrhizal species in the product because the information on the packaging can be vague or confusing. In addition, it is never a good idea to import foreign species of any kind into a planting site.
How do you know your trees will benefit from the 2 or 3 types of fungi you buy? There is no way to know that the product contains active fungi. They could all be dead. Manufactured mycorrhizal fungi inoculants are heat sensitive. If the container is left in a building or a transport truck too long, the sustained high temperatures kill the fungi.
All the positive research appears to have been done in a climate controlled site and for enhancing crop production and containerized nursery stock. While it is well known that mycorrhizal fungi are a vital part of native woodland ecosystems, it is not known if they will survive in a tree pit in a city. This is likely to be the case in many urban situations such as streets and plazas but also in highly managed landscape conditions such as domestic garden lawns, public gardens, and the manicured parts of golf courses.
If it’s not dead on arrival, mycorrhizal fungi may decline or be killed by such diverse things as fertilizer, chemical spillage, soil compaction, excess animal urine, or low humus soil conditions. When applied at the time of planting young trees or as a soil inoculant around mature trees, the trees may or may not be in a condition to exploit any benefits. Creating a good environment around a new or stressed tree by mulching may perhaps attract local mycorrhizal fungi spores into the humus so the inoculant will be a waste of time and money.
Sterile potting soil used in containers has no natural fungi. Studies have shown that adding mycorrhizal fungi to this type of environment can have some positive short term results. Keep in mind that the main value of the fungi is to help provide trees with water and nutrients. However, in a potted situation, many nurseries over water and over fertilize, negating the benefit of the fungi. If the trees are going to receive water and fertilizer regularly, adding mycorrhizal fungi is likely to be pointless.
So, mycorrhizal fungi inoculant may not be useful in an urban tree planting situation. Arborists should take this into consideration when specifying the use of inoculants when planting trees in their cities. Perhaps a shovel-full of soil dug from around the roots of an existing healthy specimen nearby, of similar species as that being planted, is just as good, if not better than an inoculant.
Also, perhaps it is worth considering that creating a mycorrhizal-friendly environment around trees by mulching the surface, adding rich humus and creating non-compacted, unpolluted soil conditions, the mycorrhizae spores may just turn up, survive and happily proliferate naturally. That is certainly what they are finding at the Royal Botanic Gardens Kew in England after some experimentation (Kirkham 2016).
A recent British Standard: BS 8545 compiled in 2014 concluded that: “The benefits of mycorrhizal associations are well documented and include a tree’s fertility requirement, its ability to absorb minerals and nitrogen from the soil, its rooting habit, and the amount of available fertility in the soil. However, there is little literature to support the value of adding commercial mycorrhizal cocktails to the backfill soil used for young tree planting”.
We, the authors, would be the first to endorse these products if convinced by peer reviewed or bona fide scientific proof that they ‘work’. Meanwhile we worry that they are nothing but snake oil.
References
· Appleton, Bonnie, et al “Mycorrhizal Fungal Inoculation of Established Street Trees ”, Journal of Arboriculture, 29(2) 107-111. March 2003.
· British Standard 8545, “Trees: from nursery to independence in the landscape – Recommendations”, 2014.
· Carlson, Julie et al, “Can Mycorrhizae Improve Tree Establishment in the Landscape?” Proceedings SNA Research Conference. 45:411-413.(2000)
· Ferrini, F. A. Fini et al, “Effect of fertilization and mycorrhizal inoculation in the nursery on post-transplant growth and physiology in three ornamental woody species”. Acta Horticulturae, 2016.
· Gilman, Edward, ”Effect of Nursery Production Method, Irrigation, and Inoculation with Mycorrhizae-Forming Fungi on Establishment of Quercus Virginiana”, Journal of Arboriculture, 27:30-38. Jan. 2001.
· Shigo, Alex, “Dictionary”, Keslick & Son Modern Arboriculture, 2008.
· Kirkham, T, Head of Arboretum, Gardens & Horticultural Services at RBG Kew – personal communication, July 2016.
Peter Thurman is an Arboricultural, Horticultural and Environmental Consultant and Landscape Designer based in East Sussex, England.
Len Phillips is Founder of Online Seminars for Municipal Arborists.
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 practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Peter Thurman and Len Phillips
In the natural environment, mycorrhizal fungi are found associated with the roots of most woody plants. They are a group of fungi that live in a symbiotic or mutually beneficial relationship with plants, by wrapping around or penetrating plant roots and then proliferating through the soil beyond the host plant’s roots - effectively extending the root system volume of the host plant's roots by hundreds of times. These fungi release enzymes which help break down nutrients into forms more easily utilized by the plant. Many researchers and arborists consider that, while this group of fungi is very important, maybe even vital, in natural conditions, there is a significant risk that they are often depleted by cultivation, chemical use, compaction, and topsoil erosion.
The Positives
Think of mycorrhizal fungi as a vast network of very fine tree roots. Although not plant roots, they behave in ways similar to them. They burrow into nooks and crannies between soil particles and collect water and nutrients for their hosts. In return, the photosynthetic process of the host trees send sugars to the fungi as food.
The uniqueness of mycorrhizal fungi lies in their ability to readily absorb elements such as phosphates, manganese, copper, and zinc dissolved in water, for use by a plant. Mycorrhizal fungi form when some fungi infect young, emerging non-woody roots. They do this in several different ways. They expand the absorbing surface as the hyphae reach out and as they grow into the soil. They also have chitin in their boundaries which is very adept at absorbing large molecules such as the phosphate molecule.
Natural phosphate in the soil and applied phosphate fertilizer particles are tightly bound to the soil particles, making it unavailable to trees. A small percentage of bound phosphate will gradually be converted into available forms, but this does not happen quickly or efficiently. At least 25% of the phosphate in soils never becomes available, making it crucial to get the most efficient use of fertilizer phosphate. Mycorrhizal fungi inoculants help to release some of the phosphate making it more available for the host plant to use.
Given this important symbiotic association, it is natural to think that it would be beneficial to add more mycorrhizal fungi to the soil.
One positive note is that once mycorrhizal fungi have attached to the rhizosphere, it stays and grows with the host as long as conditions remain suitable. However, some researchers have found that you must inoculate the plant's roots with mycorrhizal fungi. You cannot inoculate the soil with these fungi.
Nurseries will sometimes add mycorrhizal fungi to the soil around their trees and use this fact as part of their marketing strategy. Such products give 'added-value' when their product is sold, but its effectiveness is not proven.
The Problems
We can now buy mycorrhizal fungi inoculants in packets when we purchase a tree, shrub or rose bush. Many of the mycorrhizal fungi inoculant mixes are sold as very host-specific but this may not be true because the inoculant usually consists of only 2 or 3 types of fungi. It turns out that there are hundreds if not thousands of different kinds of mycorrhizal fungi in the soil where a tree may be planted and some of these mycorrhizal fungi are very specific to certain types of plants especially when it comes to trees. The manufacturer hopes that, with a large number of spores, maybe some will be responsive. Conversely, other products are sold as a do-all, fix-all cocktail, suggesting that it is suitable for a very wide range of species, but in essence, may not be true.
There is no doubt that mycorrhizae are very important, if not vital, to plants growing in the natural environment but can they be successfully ‘dropped in’ to man-made landscapes? The trouble is, we don’t know. Do they, will they ‘work’ in such scenarios – whatever the mix being offered?
Put simply, inoculants are commercial products that lack scientific trials and proof of effectiveness. There are thousands of scientific papers on mycorrhizae and commercial inoculants but most have been written by people with a vested interest in the product – such as scientists who work for the commercial manufacturer.
Furthermore, we, the authors, have failed to find any papers on successful, well-designed trials that have been peer reviewed and replicated by independent scholars or organizations that would not benefit financially from positive results. The results of one paper by independent researchers (Ferrini & Fini 2011) were only marginally positive and certainly not convincing enough to support the use of mycorrhizal inoculants.
It is very difficult to determine if an inoculant is of high quality. Some manufacturers count 'propagules' instead of 'spores.' Propagules can include root fragments and other inert materials, so the spore count might actually be much lower. Furthermore, these very specific species almost certainly are from an area that is foreign to the soil where a tree is to be planted. It is even possible that these foreign species will inhibit the growth of the native species but there is often no way of knowing the mycorrhizal species in the product because the information on the packaging can be vague or confusing. In addition, it is never a good idea to import foreign species of any kind into a planting site.
How do you know your trees will benefit from the 2 or 3 types of fungi you buy? There is no way to know that the product contains active fungi. They could all be dead. Manufactured mycorrhizal fungi inoculants are heat sensitive. If the container is left in a building or a transport truck too long, the sustained high temperatures kill the fungi.
All the positive research appears to have been done in a climate controlled site and for enhancing crop production and containerized nursery stock. While it is well known that mycorrhizal fungi are a vital part of native woodland ecosystems, it is not known if they will survive in a tree pit in a city. This is likely to be the case in many urban situations such as streets and plazas but also in highly managed landscape conditions such as domestic garden lawns, public gardens, and the manicured parts of golf courses.
If it’s not dead on arrival, mycorrhizal fungi may decline or be killed by such diverse things as fertilizer, chemical spillage, soil compaction, excess animal urine, or low humus soil conditions. When applied at the time of planting young trees or as a soil inoculant around mature trees, the trees may or may not be in a condition to exploit any benefits. Creating a good environment around a new or stressed tree by mulching may perhaps attract local mycorrhizal fungi spores into the humus so the inoculant will be a waste of time and money.
Sterile potting soil used in containers has no natural fungi. Studies have shown that adding mycorrhizal fungi to this type of environment can have some positive short term results. Keep in mind that the main value of the fungi is to help provide trees with water and nutrients. However, in a potted situation, many nurseries over water and over fertilize, negating the benefit of the fungi. If the trees are going to receive water and fertilizer regularly, adding mycorrhizal fungi is likely to be pointless.
So, mycorrhizal fungi inoculant may not be useful in an urban tree planting situation. Arborists should take this into consideration when specifying the use of inoculants when planting trees in their cities. Perhaps a shovel-full of soil dug from around the roots of an existing healthy specimen nearby, of similar species as that being planted, is just as good, if not better than an inoculant.
Also, perhaps it is worth considering that creating a mycorrhizal-friendly environment around trees by mulching the surface, adding rich humus and creating non-compacted, unpolluted soil conditions, the mycorrhizae spores may just turn up, survive and happily proliferate naturally. That is certainly what they are finding at the Royal Botanic Gardens Kew in England after some experimentation (Kirkham 2016).
A recent British Standard: BS 8545 compiled in 2014 concluded that: “The benefits of mycorrhizal associations are well documented and include a tree’s fertility requirement, its ability to absorb minerals and nitrogen from the soil, its rooting habit, and the amount of available fertility in the soil. However, there is little literature to support the value of adding commercial mycorrhizal cocktails to the backfill soil used for young tree planting”.
We, the authors, would be the first to endorse these products if convinced by peer reviewed or bona fide scientific proof that they ‘work’. Meanwhile we worry that they are nothing but snake oil.
References
· Appleton, Bonnie, et al “Mycorrhizal Fungal Inoculation of Established Street Trees ”, Journal of Arboriculture, 29(2) 107-111. March 2003.
· British Standard 8545, “Trees: from nursery to independence in the landscape – Recommendations”, 2014.
· Carlson, Julie et al, “Can Mycorrhizae Improve Tree Establishment in the Landscape?” Proceedings SNA Research Conference. 45:411-413.(2000)
· Ferrini, F. A. Fini et al, “Effect of fertilization and mycorrhizal inoculation in the nursery on post-transplant growth and physiology in three ornamental woody species”. Acta Horticulturae, 2016.
· Gilman, Edward, ”Effect of Nursery Production Method, Irrigation, and Inoculation with Mycorrhizae-Forming Fungi on Establishment of Quercus Virginiana”, Journal of Arboriculture, 27:30-38. Jan. 2001.
· Shigo, Alex, “Dictionary”, Keslick & Son Modern Arboriculture, 2008.
· Kirkham, T, Head of Arboretum, Gardens & Horticultural Services at RBG Kew – personal communication, July 2016.
Peter Thurman is an Arboricultural, Horticultural and Environmental Consultant and Landscape Designer based in East Sussex, England.
Len Phillips is Founder of Online Seminars for Municipal Arborists.
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 practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Cultivars of Kousa Dogwood
By Len Philllips
The Kousa Dogwood is best known for its resistance to dogwood anthracnose. It is also popular for its bloom that continues for four weeks after the Flowering Dogwood. The description that follows provides a summary of similarities that all the cultivars possess.
Bloom Period: Mid-May through June
Flower: Bracts, very dense on mature trees, 3" – 5" in diameter
Winter Color: Nice winter form and dark bark
Bark: Scaly, grayish brown
Habitat: Species introduced in 1875
Height and Spread: 20 feet in both directions except as noted below
Hardiness Zone: 5 – 8
Growth Rate: Vigorous and upright, full size in less than 30 years
Pest Problems: Excellent borer & anthracnose resistance
Planting: Transplant B & B or container
Pruning: Prune as needed at planting and periodically to mature form
Propagating: Budding, grafting, softwood cuttings in summer
Design Uses: Good street tree for under wires, excellent for residential landscapes
Companions: Excellent in groves with Nyssa, Ostrya, Oxydendrum, and Hydrangea
Other Comments: Very popular, an excellent substitute for C. florida, heavy flowering with firm, well formed flower bracts that stand up to wind and heat, one of the most impressive and disease resistant group of flowering cultivars.
Some of the best of the Kousa Dogwoods that are currently available are described below:
Champion’s Gold™ Dogwood Cornus kousa ‘Losely’ P.A.F. – Shape: wide vase to rounded; Flower: white.
Champion's Gold leaves emerge as green color in spring. By midsummer, any foliage exposed to direct sun takes on a bright yellow hue, creating an overall multi-colored effect. As summer progresses, the yellow tones spread and intensify until autumn arrives, when the leaves turn bright orange and red over the entire tree. It is truly a tree of many colors. Photo
Chinese Kousa Dogwood Cornus kousa chinensis – Shape: wide vase to rounded, layered branches; Foliage: medium green; Fall Color: reddish.
Four white bracts form star shaped “flowers” in June that are larger than other cultivars. This is an unusual and beautiful dogwood that is hardier, more drought tolerant, and disease resistant than C. florida. One of the most common cultivars in the trade, this selection of var. chinensis is probably composed of over a dozen very similar clones. The tree is extremely floriferous and sets a very heavy crop of fruit. This tree produces larger than average sized leaves. Photo
Heart Throb® Dogwood Cornus kousa ‘Schmred’ PP 9283 – Shape: rounded; Foliage: dark green; Fall Color: deep red; Fruit: red, ¾" diameter.
Heart Throb has large, rose pink bracts that form flower heads that reach four inches in diameter. It was introduced by Don Schmidt Nursery and selected for its handsome blooms that last for up to two months in summer. Photo
Milky Way Select Dogwood Cornus kousa ‘Milky Way Select’ – Height: 15'; Spread: 15'; Shape: rounded to wide vase; Foliage: green.
Milky Way was selected for its heavy and long lasting display of large creamy white bracts. Milky Way also features an abundance of bright orange-red fruit with a diameter of ¾" and excellent orange-red to red autumn leaf color. Photo
Prophet™ Dogwood Cornus kousa ‘Propzam’ – Shape: rounded to wide vase; Fall Color: orange to red; Fruit: red, ¾" diameter.
Creamy white, broad bracted flowers contrast beautifully with Prophet's glossy, dark green foliage. One of the fastest growing C. kousa cultivars, Prophet develops a good form quickly. The rich foliage and long lasting bracts make a very noticeable display through the summer months. Photo
Samaritan® Dogwood Cornus kousa ‘Samzam’ – Shape: rounded to wide vase; Fall Color: pinkish red; Fruit: red, ¾" diameter.
Samaritan's large creamy white bracts float above the outstanding variegated foliage. The healthy green foliage is trimmed in summer with creamy-white margins. These margins change in autumn to reddish leaves edged in pink. Consistent growth, uniform size and healthy foliage combine to produce an excellent tree. Photo
Satomi Dogwood Cornus kousa ‘Satomi’ (also listed as 'Rosabella') – Shape: vase to rounded.
Rose pink bracts perch on the top the branches of Satomi Dogwood in late spring. Raspberry-like fruits appear in late summer among the light green leaves that turn various shades of red in the fall. This is a very popular cultivar that is supposed to develop bright pink bracts. In the United States, however, the warm summers seem to dull the color. As a result, most trees have a light pink or whitish-pink bloom. The color can also vary from season to season. Photo
Summer Fun Dogwood Cornus kousa ‘Summer Fun’ – Height: 18’; Spread: 15’; Shape: rounded to wide vase; Fruit: red, ¾” diameter.
The white flower bracts of Summer Fun's late spring complement the rich, contrasting green and cream-white variegated leaves. The leaf margins are brighter white than those of other variegated dogwoods. The vivid fall tones are red, and orange, with pink margins. Photo
Summer Gold Dogwood Cornus kousa ‘Summer Gold’ PP 22765 – Height: 15’; Spread: 15’; Shape: rounded to wide vase; Fruit: red, ¾” diameter.
Summer Gold's white bracted flowers are held above bright green and golden yellow variegated foliage and are a flashy, eye catching combination in summer. In autumn, the golden margins of the two-tone foliage become pink, and then the entire leaf turns bright red. Photo
Other excellent cultivars that will require a search to find in the nursery trade include:
'Beni Fuji' – This cultivar has the deepest red-pink bracts of any C. kousa cultivar, even darker than 'Satomi'. The color may not be as bright in warm summer areas.
'Elizabeth Lustgarten' and 'Lustgarten Weeping' – Notable for their weeping habits, these two cultivars grow up to 15' high with branches that arch downwards and bear white blooms. The habit is rounded and a mature specimen is very attractive.
'Gold Star' – The center of each leaf on this cultivar has a broad gold band, with stems that are somewhat reddish. It is relatively slow-growing, but in time it does form a small to medium-size, round tree. The flower bracts are white. In the late summer, the contrast between the red fruit and gold-splashed foliage can be very striking.
'Little Beauty' – This small tree grows densely branched and may never exceed 15' tall. Other traits are similar to the species.
'Snowboy' – This cultivar sports gray-green leaves that are edged in white, with occasional splashes of variegation throughout the foliage. While the tree is attractive when well grown, it is very slow-growing and to avoid leaf scorch it should be grown in a shady location.
'Summer Stars' -- The bracts on this selection are not as large as those of other cultivars, but they are retained longer. This tree is a heavy bloomer and grows to 25' tall with a vase shape.
'Temple Jewel' --This is an interesting variegated tree with leaves that show a light marbling of green, gold, and light pink that turns mostly green with age. It grows to 20' tall and wider with a dense habit. The bracts are white.
'Variegata' -- Various similar clones of Variegata exist with differing degrees of yellow or white variegation. The pattern may be unstable, plus the trees can produce green leaf reversions. Most are slower growing and will benefit from growing in some shade.
'Wolf Eyes' -- This is a very popular variegated form with leaves that show a uniform white margin. The leaf margins are often prominently wavy. The variegation pattern is quite stable and resistant to burning, although a shaded planting site is still desirable. In autumn, the leaves develop attractive pink to red coloration. The tree is shrubby, slow-growing, and only to 10' tall and wide.
Sources
This information has been gathered from personal observations of the author, living in Massachusetts, Zone 6, and information provided by J. Frank Schmidt & Son nursery.
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 practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com’. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Len Philllips
The Kousa Dogwood is best known for its resistance to dogwood anthracnose. It is also popular for its bloom that continues for four weeks after the Flowering Dogwood. The description that follows provides a summary of similarities that all the cultivars possess.
Bloom Period: Mid-May through June
Flower: Bracts, very dense on mature trees, 3" – 5" in diameter
Winter Color: Nice winter form and dark bark
Bark: Scaly, grayish brown
Habitat: Species introduced in 1875
Height and Spread: 20 feet in both directions except as noted below
Hardiness Zone: 5 – 8
Growth Rate: Vigorous and upright, full size in less than 30 years
Pest Problems: Excellent borer & anthracnose resistance
Planting: Transplant B & B or container
Pruning: Prune as needed at planting and periodically to mature form
Propagating: Budding, grafting, softwood cuttings in summer
Design Uses: Good street tree for under wires, excellent for residential landscapes
Companions: Excellent in groves with Nyssa, Ostrya, Oxydendrum, and Hydrangea
Other Comments: Very popular, an excellent substitute for C. florida, heavy flowering with firm, well formed flower bracts that stand up to wind and heat, one of the most impressive and disease resistant group of flowering cultivars.
Some of the best of the Kousa Dogwoods that are currently available are described below:
Champion’s Gold™ Dogwood Cornus kousa ‘Losely’ P.A.F. – Shape: wide vase to rounded; Flower: white.
Champion's Gold leaves emerge as green color in spring. By midsummer, any foliage exposed to direct sun takes on a bright yellow hue, creating an overall multi-colored effect. As summer progresses, the yellow tones spread and intensify until autumn arrives, when the leaves turn bright orange and red over the entire tree. It is truly a tree of many colors. Photo
Chinese Kousa Dogwood Cornus kousa chinensis – Shape: wide vase to rounded, layered branches; Foliage: medium green; Fall Color: reddish.
Four white bracts form star shaped “flowers” in June that are larger than other cultivars. This is an unusual and beautiful dogwood that is hardier, more drought tolerant, and disease resistant than C. florida. One of the most common cultivars in the trade, this selection of var. chinensis is probably composed of over a dozen very similar clones. The tree is extremely floriferous and sets a very heavy crop of fruit. This tree produces larger than average sized leaves. Photo
Heart Throb® Dogwood Cornus kousa ‘Schmred’ PP 9283 – Shape: rounded; Foliage: dark green; Fall Color: deep red; Fruit: red, ¾" diameter.
Heart Throb has large, rose pink bracts that form flower heads that reach four inches in diameter. It was introduced by Don Schmidt Nursery and selected for its handsome blooms that last for up to two months in summer. Photo
Milky Way Select Dogwood Cornus kousa ‘Milky Way Select’ – Height: 15'; Spread: 15'; Shape: rounded to wide vase; Foliage: green.
Milky Way was selected for its heavy and long lasting display of large creamy white bracts. Milky Way also features an abundance of bright orange-red fruit with a diameter of ¾" and excellent orange-red to red autumn leaf color. Photo
Prophet™ Dogwood Cornus kousa ‘Propzam’ – Shape: rounded to wide vase; Fall Color: orange to red; Fruit: red, ¾" diameter.
Creamy white, broad bracted flowers contrast beautifully with Prophet's glossy, dark green foliage. One of the fastest growing C. kousa cultivars, Prophet develops a good form quickly. The rich foliage and long lasting bracts make a very noticeable display through the summer months. Photo
Samaritan® Dogwood Cornus kousa ‘Samzam’ – Shape: rounded to wide vase; Fall Color: pinkish red; Fruit: red, ¾" diameter.
Samaritan's large creamy white bracts float above the outstanding variegated foliage. The healthy green foliage is trimmed in summer with creamy-white margins. These margins change in autumn to reddish leaves edged in pink. Consistent growth, uniform size and healthy foliage combine to produce an excellent tree. Photo
Satomi Dogwood Cornus kousa ‘Satomi’ (also listed as 'Rosabella') – Shape: vase to rounded.
Rose pink bracts perch on the top the branches of Satomi Dogwood in late spring. Raspberry-like fruits appear in late summer among the light green leaves that turn various shades of red in the fall. This is a very popular cultivar that is supposed to develop bright pink bracts. In the United States, however, the warm summers seem to dull the color. As a result, most trees have a light pink or whitish-pink bloom. The color can also vary from season to season. Photo
Summer Fun Dogwood Cornus kousa ‘Summer Fun’ – Height: 18’; Spread: 15’; Shape: rounded to wide vase; Fruit: red, ¾” diameter.
The white flower bracts of Summer Fun's late spring complement the rich, contrasting green and cream-white variegated leaves. The leaf margins are brighter white than those of other variegated dogwoods. The vivid fall tones are red, and orange, with pink margins. Photo
Summer Gold Dogwood Cornus kousa ‘Summer Gold’ PP 22765 – Height: 15’; Spread: 15’; Shape: rounded to wide vase; Fruit: red, ¾” diameter.
Summer Gold's white bracted flowers are held above bright green and golden yellow variegated foliage and are a flashy, eye catching combination in summer. In autumn, the golden margins of the two-tone foliage become pink, and then the entire leaf turns bright red. Photo
Other excellent cultivars that will require a search to find in the nursery trade include:
'Beni Fuji' – This cultivar has the deepest red-pink bracts of any C. kousa cultivar, even darker than 'Satomi'. The color may not be as bright in warm summer areas.
'Elizabeth Lustgarten' and 'Lustgarten Weeping' – Notable for their weeping habits, these two cultivars grow up to 15' high with branches that arch downwards and bear white blooms. The habit is rounded and a mature specimen is very attractive.
'Gold Star' – The center of each leaf on this cultivar has a broad gold band, with stems that are somewhat reddish. It is relatively slow-growing, but in time it does form a small to medium-size, round tree. The flower bracts are white. In the late summer, the contrast between the red fruit and gold-splashed foliage can be very striking.
'Little Beauty' – This small tree grows densely branched and may never exceed 15' tall. Other traits are similar to the species.
'Snowboy' – This cultivar sports gray-green leaves that are edged in white, with occasional splashes of variegation throughout the foliage. While the tree is attractive when well grown, it is very slow-growing and to avoid leaf scorch it should be grown in a shady location.
'Summer Stars' -- The bracts on this selection are not as large as those of other cultivars, but they are retained longer. This tree is a heavy bloomer and grows to 25' tall with a vase shape.
'Temple Jewel' --This is an interesting variegated tree with leaves that show a light marbling of green, gold, and light pink that turns mostly green with age. It grows to 20' tall and wider with a dense habit. The bracts are white.
'Variegata' -- Various similar clones of Variegata exist with differing degrees of yellow or white variegation. The pattern may be unstable, plus the trees can produce green leaf reversions. Most are slower growing and will benefit from growing in some shade.
'Wolf Eyes' -- This is a very popular variegated form with leaves that show a uniform white margin. The leaf margins are often prominently wavy. The variegation pattern is quite stable and resistant to burning, although a shaded planting site is still desirable. In autumn, the leaves develop attractive pink to red coloration. The tree is shrubby, slow-growing, and only to 10' tall and wide.
Sources
This information has been gathered from personal observations of the author, living in Massachusetts, Zone 6, and information provided by J. Frank Schmidt & Son nursery.
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 practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com’. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Nematodes
Edited by Len Phillips
Plant-parasitic nematodes can reduce both the quantity and quality of the yield in a landscape and cause the untimely decline of trees. Plants infected with nematodes are predisposed to infection with other diseases, are less tolerant to drought stress, and cannot utilize fertilizer efficiently.
Root-knot Nematodes
Although various kinds of plant-parasitic nematodes are responsible for poor plant growth, root-knot nematodes are the most important. They can cause severe problems that result in substantial yield suppression for many plants. Root-knot nematodes can parasitize a broad range of plant species.
Root-knot nematodes, as their name implies, cause the production of large galls on the root systems of infected plants. Specialized cells within these galls drain energy away from the plant. This energy is utilized by the enlarged, pear-shaped females for the production of numerous eggs that develop into more nematodes capable of penetrating additional roots and causing more galls.
Root-knot nematodes are difficult to control by non-chemical means because they can reproduce on many different plants including numerous weed species. In addition, root-knot nematodes are genetically diverse and can adapt in response to the use of resistant cultivars. Continued planting of a nematode-resistant species may cause a shift in the nematode population so that the number of nematodes able to reproduce on the resistant varieties will increase each growing season until finally the resistance is of no value. Resistant cultivars should, therefore, be used in rotation with susceptible cultivars and other control practices.
Control
Adequate control of nematodes can be obtained by using certain nematicides, by crop rotations, by planting resistant cultivars, and by using organic mulches and green manures. Root-knot nematodes can also be avoided by not importing them from infected transplants or infested soil. Introduction of a root-knot nematode can be prevented by starting seedlings in a sterile media or by buying them from a reputable supplier. Topsoil should be sampled for nematodes prior to the introduction into a new area. If root-knot nematodes are detected, fumigate the soil before planting anything.
Nematodes on Landscape Trees
Many landscape trees are susceptible to infestation by common root-knot nematodes. A few nematodes with restricted host specificity have been found on several tree species and it is likely that more will be found in the future. The direct effects of nematodes on tree growth may not be readily apparent but the synergism between nematodes and fungi such as Fusarium and Verticillium can result in the death of trees considered resistant or tolerant to the wilt pathogens. Arborists, horticulturists, and nurserymen should consider at least a cursory examination of root systems when investigating the causes of poor plant performance.
The four most common root-knot nematodes in the Northern Hemisphere (Meloidogyne arenaria, M. hapla, M. incognita, M. javanica) have a broad host range among crop plants. Some trees growing naturally or under cultivation were found to be susceptible to one or more of these nematodes, with obvious above-ground symptoms of infestation.
Nematodes on Willows
The "true" weeping willow (S. babylonica 'Babylon') was susceptible to all of the nematodes except M. hapla, as were the 25 other weeping, possibly hybrid, clones from various arboretum collections. The European S. alba, which may have been the other species parent of these weeping selections, was similarly susceptible. The only tree-type willow on which the nematodes did not reproduce was the American black willow (S. nigra).
Nematodes on Oaks
A survey of oaks encompassed 32 species, including representatives of the five subgenera of Quercus, revealed that only the Asiatic and European oaks were susceptible to any of the four common nematode species.
Nematodes on Maples
Eighteen species of maples (Acer), representing 11 botanical sections of the genus, were surveyed for susceptibility to the four common nematode species and the oak root-knot nematode. The maple species varied widely in their response to nematode inoculation, with some species even being susceptible to M. hapla, which did not parasitize any of the willows or oaks. None of the nematodes were capable of reproduction on red maple (A. rubrum), silver maple (A. saccharinum), and Norway maple (A. platanoides).
Nematodes on Various Trees
The most recent study examined the nematode susceptibility of 23 species in 17 genera of landscape trees, including many widely planted species. Many urban trees including Ailanthus altissima, Gleditsia triacanthos, Liquidambar styraciflua, Magnolia grandiflora, and Pyrus callervana were resistant to all the common root-knot nematodes. On the other hand, Ginkgo biloba, Koelreuteria paniculata, Robinia pseudaacacia, Sophora japonica, Ulmus parvifolia, Zelkova serrata, and some species of Betula and Prunus were susceptible to one or more of the common nematodes.
Nematode-fungus Synergism
The cultivar Acer platanoides 'Jade Glen', which was considered highly tolerant of vertlcilllum wilt, was susceptible to three common root-knot nematode species. None of the nematodes were able to reproduce on the roots of another wilt-tolerant cultivar A. platanoides 'Parkway' and no plants wilted. The wilt-susceptible cultivars, A. platanoides 'Crimson King' and A. platanoides 'Greenlace' did show wilt symptoms, but they were highly resistant to the nematodes. Thus the synergistic action of the fungus-nematode combination is not necessary for wilt to occur in Norway maples but it has been shown that some selected wilt-tolerant trees might exhibit severe wilt symptoms if they are successfully attacked by nematodes.
In another study, 6,000 seediings of Albizia julibrssin, derived from inter-pollination among trees selected for resistance to Fusarium wilt, were inoculated with a combination of the wilt fungus and two root-knot nematodes. Of 78 plants that survived this intensive screening, only 20 were symptomless after eight years of field-testing. The best of these are now being propagated for wider testing and eventual release as superior disease-resistant cultivars.
At the present time, arborists should not overestimate the deleterious effects of root-knot nematodes on landscape trees. Combinations of root-knot nematodes and certain wilt pathogens may cause considerable damage to trees. It is possible that there may also be synergistic situations, similar to important root-rot pathogens such as Armillaria. Arborists and other professionals who deal with the planting maintenance and care of trees in the landscape should be aware that root-knot nematodes are potentially important pests and that the examination of tree root systems should be an integral part of their diagnoses of tree problems.
Recent Research
· Cercis Resistance - Large-scale generic surveys of nematode susceptibility is the recent breeding work at the US National Arboretum to develop superior disease-resistant cultivars of Cercis. They are currently evaluating the nematode susceptibility of several species of Cercis and certain provenances of C. canadensis as part of this program.
· Nematode Resistance in Albizia - Another study is underway to determine the potential inheritance of nematode resistance in Albizia.
Sources
· Eisenback, Jon D., "Gardening with Root-Knot Nematodes,"The Virginia Gardener Newsletter”, Department of Plant Pathology, Virginia Tech, Volume 6, Number 6, 1997
· Neely, Dan, and Gary Watson, "The Landscape Below Ground II", International Society of Arboriculture, 1998.
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 practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
Plant-parasitic nematodes can reduce both the quantity and quality of the yield in a landscape and cause the untimely decline of trees. Plants infected with nematodes are predisposed to infection with other diseases, are less tolerant to drought stress, and cannot utilize fertilizer efficiently.
Root-knot Nematodes
Although various kinds of plant-parasitic nematodes are responsible for poor plant growth, root-knot nematodes are the most important. They can cause severe problems that result in substantial yield suppression for many plants. Root-knot nematodes can parasitize a broad range of plant species.
Root-knot nematodes, as their name implies, cause the production of large galls on the root systems of infected plants. Specialized cells within these galls drain energy away from the plant. This energy is utilized by the enlarged, pear-shaped females for the production of numerous eggs that develop into more nematodes capable of penetrating additional roots and causing more galls.
Root-knot nematodes are difficult to control by non-chemical means because they can reproduce on many different plants including numerous weed species. In addition, root-knot nematodes are genetically diverse and can adapt in response to the use of resistant cultivars. Continued planting of a nematode-resistant species may cause a shift in the nematode population so that the number of nematodes able to reproduce on the resistant varieties will increase each growing season until finally the resistance is of no value. Resistant cultivars should, therefore, be used in rotation with susceptible cultivars and other control practices.
Control
Adequate control of nematodes can be obtained by using certain nematicides, by crop rotations, by planting resistant cultivars, and by using organic mulches and green manures. Root-knot nematodes can also be avoided by not importing them from infected transplants or infested soil. Introduction of a root-knot nematode can be prevented by starting seedlings in a sterile media or by buying them from a reputable supplier. Topsoil should be sampled for nematodes prior to the introduction into a new area. If root-knot nematodes are detected, fumigate the soil before planting anything.
Nematodes on Landscape Trees
Many landscape trees are susceptible to infestation by common root-knot nematodes. A few nematodes with restricted host specificity have been found on several tree species and it is likely that more will be found in the future. The direct effects of nematodes on tree growth may not be readily apparent but the synergism between nematodes and fungi such as Fusarium and Verticillium can result in the death of trees considered resistant or tolerant to the wilt pathogens. Arborists, horticulturists, and nurserymen should consider at least a cursory examination of root systems when investigating the causes of poor plant performance.
The four most common root-knot nematodes in the Northern Hemisphere (Meloidogyne arenaria, M. hapla, M. incognita, M. javanica) have a broad host range among crop plants. Some trees growing naturally or under cultivation were found to be susceptible to one or more of these nematodes, with obvious above-ground symptoms of infestation.
Nematodes on Willows
The "true" weeping willow (S. babylonica 'Babylon') was susceptible to all of the nematodes except M. hapla, as were the 25 other weeping, possibly hybrid, clones from various arboretum collections. The European S. alba, which may have been the other species parent of these weeping selections, was similarly susceptible. The only tree-type willow on which the nematodes did not reproduce was the American black willow (S. nigra).
Nematodes on Oaks
A survey of oaks encompassed 32 species, including representatives of the five subgenera of Quercus, revealed that only the Asiatic and European oaks were susceptible to any of the four common nematode species.
Nematodes on Maples
Eighteen species of maples (Acer), representing 11 botanical sections of the genus, were surveyed for susceptibility to the four common nematode species and the oak root-knot nematode. The maple species varied widely in their response to nematode inoculation, with some species even being susceptible to M. hapla, which did not parasitize any of the willows or oaks. None of the nematodes were capable of reproduction on red maple (A. rubrum), silver maple (A. saccharinum), and Norway maple (A. platanoides).
Nematodes on Various Trees
The most recent study examined the nematode susceptibility of 23 species in 17 genera of landscape trees, including many widely planted species. Many urban trees including Ailanthus altissima, Gleditsia triacanthos, Liquidambar styraciflua, Magnolia grandiflora, and Pyrus callervana were resistant to all the common root-knot nematodes. On the other hand, Ginkgo biloba, Koelreuteria paniculata, Robinia pseudaacacia, Sophora japonica, Ulmus parvifolia, Zelkova serrata, and some species of Betula and Prunus were susceptible to one or more of the common nematodes.
Nematode-fungus Synergism
The cultivar Acer platanoides 'Jade Glen', which was considered highly tolerant of vertlcilllum wilt, was susceptible to three common root-knot nematode species. None of the nematodes were able to reproduce on the roots of another wilt-tolerant cultivar A. platanoides 'Parkway' and no plants wilted. The wilt-susceptible cultivars, A. platanoides 'Crimson King' and A. platanoides 'Greenlace' did show wilt symptoms, but they were highly resistant to the nematodes. Thus the synergistic action of the fungus-nematode combination is not necessary for wilt to occur in Norway maples but it has been shown that some selected wilt-tolerant trees might exhibit severe wilt symptoms if they are successfully attacked by nematodes.
In another study, 6,000 seediings of Albizia julibrssin, derived from inter-pollination among trees selected for resistance to Fusarium wilt, were inoculated with a combination of the wilt fungus and two root-knot nematodes. Of 78 plants that survived this intensive screening, only 20 were symptomless after eight years of field-testing. The best of these are now being propagated for wider testing and eventual release as superior disease-resistant cultivars.
At the present time, arborists should not overestimate the deleterious effects of root-knot nematodes on landscape trees. Combinations of root-knot nematodes and certain wilt pathogens may cause considerable damage to trees. It is possible that there may also be synergistic situations, similar to important root-rot pathogens such as Armillaria. Arborists and other professionals who deal with the planting maintenance and care of trees in the landscape should be aware that root-knot nematodes are potentially important pests and that the examination of tree root systems should be an integral part of their diagnoses of tree problems.
Recent Research
· Cercis Resistance - Large-scale generic surveys of nematode susceptibility is the recent breeding work at the US National Arboretum to develop superior disease-resistant cultivars of Cercis. They are currently evaluating the nematode susceptibility of several species of Cercis and certain provenances of C. canadensis as part of this program.
· Nematode Resistance in Albizia - Another study is underway to determine the potential inheritance of nematode resistance in Albizia.
Sources
· Eisenback, Jon D., "Gardening with Root-Knot Nematodes,"The Virginia Gardener Newsletter”, Department of Plant Pathology, Virginia Tech, Volume 6, Number 6, 1997
· Neely, Dan, and Gary Watson, "The Landscape Below Ground II", International Society of Arboriculture, 1998.
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 practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Recycling Water
Edited by Len Phillips
Trees and landscapes all need essential water every day. Fortunately, trees and landscapes are very tolerant of water whether it is rainfall, ground water, or recycled water. Through the natural water cycle, the earth has recycled and reused water for millions of years. Water recycling today, generally refers to projects that use technology to speed up these natural processes.
Water recycling is often characterized as "unplanned" or "planned." A common example of unplanned water recycling occurs when cities draw their water supply from rivers, such as the Mississippi River, that receive wastewater discharges upstream from downstream cities. Water from these rivers has been used, treated, and piped into the water supply a number of times before the last downstream city withdraws the water. Planned projects are those that are developed with the goal of reusing a recycled water supply for beneficial purposes such as agricultural and landscape irrigation as well as industrial processes and replenishing a ground water basin or ground water recharge. Water recycling offers resource and financial savings. Wastewater treatment can be tailored to meet the water quality requirements of a planned reuse.
Benefits of Recycled Water
Recycled water can satisfy most water demands, as long as it is adequately treated to ensure water quality appropriate for the use. In situations where there is a greater chance of human exposure to the water, more treatment is required. As for any water source that is not properly treated, health problems could arise from drinking (potable) or being exposed to recycled water (non-potable) if it contains disease-causing organisms or other contaminants.
The United States Environmental Protection Agency developed a large, detailed, technical document entitled “Guidelines for Water Reuse” which contains a summary of the requirements and guidelines for the treatment and uses of recycled water. State and Federal regulatory oversight has successfully provided a framework to ensure the safety of the many water recycling projects that have been developed in the U.S.
Recycled water is most commonly used for non-potable purposes, such as agriculture, landscapes, public parks, and golf course irrigation. Other non-potable applications include cooling water for power plants and oil refineries, industrial process water for such facilities as paper mills and carpet dyers, toilet flushing, dust control, construction activities, concrete mixing, and artificial lakes.
Although most water recycling projects have been developed to meet non-potable water demands, a number of projects use recycled water indirectly for potable purposes. These projects include recharging ground water aquifers and augmenting surface water reservoirs with recycled water. In ground water recharge projects, recycled water can be spread or injected into ground water aquifers to augment ground water supplies, and to prevent salt water intrusion in coastal areas. For example, since 1976, the Water Factory 21 Direct Injection Project, located in Orange County, California, has been injecting highly treated recycled water into the aquifer to prevent salt water intrusion, while augmenting the potable ground water supply.
While numerous successful ground water recharge projects have been operated for many years, planned augmentation of surface water reservoirs has been less common. However, there are some existing projects and others in the planning stages. For example, since 1978, the upper Occoquan Sewage Authority has been discharging recycled water into a stream above Occoquan Reservoir, a potable water supply source for Fairfax County, Virginia. In San Diego, California, the Indirect Potable Reuse Reservoir Augmentation Project augments the San Vicente Reservoir with 12,000 acre-feet per year of recycled water treated at a new Advanced Water Treatment Plant.
Soft Water
Soft water is free from the dissolved salts of such metals as calcium, iron, or magnesium, which form insoluble deposits that appear as scale in boilers or soap curds in bathtubs and laundry equipment.
Soft water is surface water that contains low concentrations of ions and in particular is low in ions of calcium and magnesium. Soft water naturally occurs where rainfall and the drainage basin of rivers are formed of hard, impervious and calcium poor rocks. The term may also be used to describe water that has been produced by a water softening process although such water is more correctly termed “softened water”. In these cases the water may also contain elevated levels of sodium and/or bicarbonate ions. Because soft water has few calcium ions, there is no inhibition to the action of soaps and no soap scum is formed in normal washing. Similarly, soft water produces no calcium deposits in water heating systems.
Hard Water
Hard water has a high mineral content. Hard water is formed when water percolates through deposits of limestone and chalk which are largely made up of calcium and magnesium carbonates.
Hard drinking water may have moderate health benefits, but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling towers, and other equipment that handles water. In domestic settings, hard water is often indicated by a lack of suds formation when soap is agitated in water, and by the formation of limescale in kettles and water heaters. Wherever water hardness is a concern, water softening equipment is commonly used to reduce hard water's adverse effects.
Gray water
Gray water is the planned reusable wastewater from residential, commercial, and industrial bathroom sinks, bath tub and shower drains, and clothes washing equipment drains. Gray water is reused on the site, typically for landscape irrigation. The use of non toxic and low-sodium soap and personal care products is required to protect vegetation when reusing gray water for irrigation. There are no documented cases of human health problems due to contact with recycled water that has been treated to improve water quality.
Domestic use of gray water
Recycled water for landscape irrigation requires less treatment than recycled water for human consumption. The use of gray water for landscape irrigation and toilet flushing reduces the amount of potable water distributed to these sites, the amount of fertilizer needed, and the amount of wastewater generated, transported, and treated at wastewater treatment facilities. In other words, water reuse saves potable water, energy, and money.
Decentralized water reuse systems are being used more in the arid western U.S. regions where long term drought conditions exist. Successful gray water systems have been operating for many years. They can meet up to 50% of a property's water needs by supplying water for landscaping. Recycling gray water saves fresh potable water for other uses, reduces the volume of wastewater going to septic systems and wastewater treatment plants, and increases infrastructure capacity for new users.
Benefits of Water Recycling
In addition to providing a dependable, locally-controlled water supply, water recycling provides tremendous environmental benefits. By providing an additional source of water, water recycling can help decrease the diversion of water from sensitive ecosystems. Other benefits include decreasing wastewater discharges and reducing and preventing pollution. Recycled water can also be used to water newly planted trees, create or enhance wetlands and riparian habitats.
Sources
· Ward, Laura, “Benefits of Recycling Rainwater” University of Missouri, 2009.
· Environmental Protection Agency, “Water Sense”, Office of Wastewater Management, 2014.
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 Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
Trees and landscapes all need essential water every day. Fortunately, trees and landscapes are very tolerant of water whether it is rainfall, ground water, or recycled water. Through the natural water cycle, the earth has recycled and reused water for millions of years. Water recycling today, generally refers to projects that use technology to speed up these natural processes.
Water recycling is often characterized as "unplanned" or "planned." A common example of unplanned water recycling occurs when cities draw their water supply from rivers, such as the Mississippi River, that receive wastewater discharges upstream from downstream cities. Water from these rivers has been used, treated, and piped into the water supply a number of times before the last downstream city withdraws the water. Planned projects are those that are developed with the goal of reusing a recycled water supply for beneficial purposes such as agricultural and landscape irrigation as well as industrial processes and replenishing a ground water basin or ground water recharge. Water recycling offers resource and financial savings. Wastewater treatment can be tailored to meet the water quality requirements of a planned reuse.
Benefits of Recycled Water
Recycled water can satisfy most water demands, as long as it is adequately treated to ensure water quality appropriate for the use. In situations where there is a greater chance of human exposure to the water, more treatment is required. As for any water source that is not properly treated, health problems could arise from drinking (potable) or being exposed to recycled water (non-potable) if it contains disease-causing organisms or other contaminants.
The United States Environmental Protection Agency developed a large, detailed, technical document entitled “Guidelines for Water Reuse” which contains a summary of the requirements and guidelines for the treatment and uses of recycled water. State and Federal regulatory oversight has successfully provided a framework to ensure the safety of the many water recycling projects that have been developed in the U.S.
Recycled water is most commonly used for non-potable purposes, such as agriculture, landscapes, public parks, and golf course irrigation. Other non-potable applications include cooling water for power plants and oil refineries, industrial process water for such facilities as paper mills and carpet dyers, toilet flushing, dust control, construction activities, concrete mixing, and artificial lakes.
Although most water recycling projects have been developed to meet non-potable water demands, a number of projects use recycled water indirectly for potable purposes. These projects include recharging ground water aquifers and augmenting surface water reservoirs with recycled water. In ground water recharge projects, recycled water can be spread or injected into ground water aquifers to augment ground water supplies, and to prevent salt water intrusion in coastal areas. For example, since 1976, the Water Factory 21 Direct Injection Project, located in Orange County, California, has been injecting highly treated recycled water into the aquifer to prevent salt water intrusion, while augmenting the potable ground water supply.
While numerous successful ground water recharge projects have been operated for many years, planned augmentation of surface water reservoirs has been less common. However, there are some existing projects and others in the planning stages. For example, since 1978, the upper Occoquan Sewage Authority has been discharging recycled water into a stream above Occoquan Reservoir, a potable water supply source for Fairfax County, Virginia. In San Diego, California, the Indirect Potable Reuse Reservoir Augmentation Project augments the San Vicente Reservoir with 12,000 acre-feet per year of recycled water treated at a new Advanced Water Treatment Plant.
Soft Water
Soft water is free from the dissolved salts of such metals as calcium, iron, or magnesium, which form insoluble deposits that appear as scale in boilers or soap curds in bathtubs and laundry equipment.
Soft water is surface water that contains low concentrations of ions and in particular is low in ions of calcium and magnesium. Soft water naturally occurs where rainfall and the drainage basin of rivers are formed of hard, impervious and calcium poor rocks. The term may also be used to describe water that has been produced by a water softening process although such water is more correctly termed “softened water”. In these cases the water may also contain elevated levels of sodium and/or bicarbonate ions. Because soft water has few calcium ions, there is no inhibition to the action of soaps and no soap scum is formed in normal washing. Similarly, soft water produces no calcium deposits in water heating systems.
Hard Water
Hard water has a high mineral content. Hard water is formed when water percolates through deposits of limestone and chalk which are largely made up of calcium and magnesium carbonates.
Hard drinking water may have moderate health benefits, but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling towers, and other equipment that handles water. In domestic settings, hard water is often indicated by a lack of suds formation when soap is agitated in water, and by the formation of limescale in kettles and water heaters. Wherever water hardness is a concern, water softening equipment is commonly used to reduce hard water's adverse effects.
Gray water
Gray water is the planned reusable wastewater from residential, commercial, and industrial bathroom sinks, bath tub and shower drains, and clothes washing equipment drains. Gray water is reused on the site, typically for landscape irrigation. The use of non toxic and low-sodium soap and personal care products is required to protect vegetation when reusing gray water for irrigation. There are no documented cases of human health problems due to contact with recycled water that has been treated to improve water quality.
Domestic use of gray water
Recycled water for landscape irrigation requires less treatment than recycled water for human consumption. The use of gray water for landscape irrigation and toilet flushing reduces the amount of potable water distributed to these sites, the amount of fertilizer needed, and the amount of wastewater generated, transported, and treated at wastewater treatment facilities. In other words, water reuse saves potable water, energy, and money.
Decentralized water reuse systems are being used more in the arid western U.S. regions where long term drought conditions exist. Successful gray water systems have been operating for many years. They can meet up to 50% of a property's water needs by supplying water for landscaping. Recycling gray water saves fresh potable water for other uses, reduces the volume of wastewater going to septic systems and wastewater treatment plants, and increases infrastructure capacity for new users.
Benefits of Water Recycling
In addition to providing a dependable, locally-controlled water supply, water recycling provides tremendous environmental benefits. By providing an additional source of water, water recycling can help decrease the diversion of water from sensitive ecosystems. Other benefits include decreasing wastewater discharges and reducing and preventing pollution. Recycled water can also be used to water newly planted trees, create or enhance wetlands and riparian habitats.
Sources
· Ward, Laura, “Benefits of Recycling Rainwater” University of Missouri, 2009.
· Environmental Protection Agency, “Water Sense”, Office of Wastewater Management, 2014.
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 Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.