Seminar #67 from Online Seminars for Municipal Arborists – March / April 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 and photos
Case Study
Stockholm Tree Pits
Edited by Len Phillips
Stockholm, the capital city of Sweden has developed a very successful tree planting program that many experts believe produces better tree growth than almost all the other methods (see Topic 18) developed for planting trees in downtown city sidewalks. Here is the Stockholm Tree Pits story.
Background
In 2001, Bjorn Embren was appointed to review the tree planting program in Stockholm. He began a working group including Britt-Marie Alvem, Örjan Stål, and Alf Orvesten, all well-known experts and researchers of tree roots. They also consulted with the Agricultural University of Stockholm and the University of Helsinki. They conducted a review of how trees grew in the urban environment and determined that soil conditions are most important for the establishment, development, and survival of trees in the city. They also collaborated with Klaus Schroder, a retired tree officer from Germany, who is credited with being the first person in Europe to work with structural soil.
In Stockholm center, about 20,000 street trees were dying because the city soils were lacking oxygen, water, and organic matter, plus a surplus of road salt, carbon dioxide, vehicle compaction, utility installation, and maintenance disruption were poisoning the trees.
Construction practices before 2001 required that all pavement be heavily compacted so rain water would run to the storm drains instead of the soil to discourage tree roots from growing under the pavements and causing pavement failure. Over time, the lack of water in the soils caused a decline in the trees, but more importantly, older buildings began to settle, shift, and destabilize, often requiring complete reconstruction.
In his search for answers, Mr. Embren and his team, discovered that along the railways in Stockholm, trees were growing extremely well in the stone ballast beside the tracks. The rocks in the ballast were large but stable and perhaps the same large stone could be used under the pavements in the city to allow root growth in the voids between the stones, and the stone would transfer the vehicle weight to the solid soil at the bottom of the planting pit. He also determined that the best soil conditions for trees roots surrounding the stone should consist of a homogeneous soil where the particle size distribution and humus content is mixed throughout the upper 12 inches (30 cm) of soil and the same soil minus the humus is located under this “topsoil”.
Based upon all the experts' research, and a process of trial and error, the tree planting team in the city developed a structural soil that consists of layers of 4 – 6 inch (10-15 cm) crushed rocks, installed in 10 – 12 inch (25-30 cm) thick layers. This resulted in about 25% – 30% pore space that is filled with soil. The rocks could be any available native stone, but Mr. Embren felt it would be much better to use broken up recycled concrete sidewalks instead of the native granite. Thus began an effort to plant new trees in stone filled trenches throughout the city.
Planter Construction
A deep trench or pit is dug 30 – 40 in. (0.8-1 m.) deep and rocks are placed at the bottom 24 inches (60 cm). When the first layer of stone is compacted, soil is lightly sprinkled on top of the rocks. The soil is then washed into the voids between each stone with high pressure water. The process is repeated until the voids in the rock are filled with soil. A slow-release fertilizer is sprinkled over the stone/soil mix of each layer. A second layer of stone is added on top of the previous layer and soil with humus is washed in to this layer of stone.
On the top of the compacted stone, corner pads are placed for the installation of a square precast concrete box for the tree. The bottom and holes on the side of the box are open to the compacted stone/soil mix. When the project is completed, the trees are planted in the box so the roots may grow down and into the stone/soil planting area. If the tree needs replacement, the old tree is easily removed from the concrete box and a new tree planted in the same box.
When the structural soil has reached the finished grade, a layer of finely crushed stone is laid on the top to level off the top of the stone. Geotextile fabric is laid over the entire planting pit followed by a base material for the pavement and the surface layer for the specific paving of the road, sidewalk, or bike path to be installed. The fabric prevents the pavement base material from migrating down into the planting soil mix and prevent roots from growing up into the base material.
The nutrient rich homogeneous mix of soil guarantees a good rooting space while the rock meets the bearing capacity demands for heavy traffic. The planting loam must also contain 5% – 8% humus, 4% – 8% clay, and a fertilizer based on need determined by a soil test. Mr. Embren developed structural soil combinations for the four different soil types found in the city. Each tree needs a minimum of 500 cu. ft. (15 cu. m.) and a space at least 7 ft. (2 m.) wide for small trees and 15 ft. (4 m.) wide for large trees. The length should be as long as possible to achieve a mature, healthy tree. Whenever possible the tree pits are connected together so the root space can be shared by all the trees.
Water Treatment
The whole area is also used for stormwater containment. Drainage basins sit in the top of stone/soil mix so water running off the surface pavement is able to flow down, through the stone and into the root zone of the trees. As the water flows through the stone/soil mix it is used by the trees. Any surplus water is emptied into the original storm drain for the street. The catch basins in the new construction are built with a metal screen near the bottom where oxygen can also enter the soil/stone mix. The oxygen is absorbed by the tree roots and prevents stagnation of the water. Catch basins beside the street curbs and building gutters also provide water to the tree. Fortunately, salt used on the streets in winter does not seem to cause a problem in the soil or with the tree roots because of the high volume of water flowing through the stone/soil mix.
Dealing with Trees
New trees of the right size and species to fit the planned dimensions and location should be delivered to the site and planted in the conventional manner within the concrete box. New trees are generally large, balled and burlapped, and planted directly on top of the stone base and in contact with the soil filled pores. If the existing trees are to be retained, the soil should be washed off the roots of the tree. The roots are then covered with a small size stone near the trunk, that gradually increase in size to meet the large stone installed in the trench. Soil is washed into this stone as it was in the rest of the planting trench.
Like every urban tree planting, several factors must be considered before actually planting the tree.
Since the Stockholm Tree Pits program began, over 2,000 projects have been completed within the city, and the Swedish national government has accepted this concept for all future projects in the country. This program resulted in tree growth that is equal to or better than trees growing in nearby parks. It seems that all trees, regardless of species have thrived in this program. Tree experts from nurseries and other cities all remark at how well the trees in Stockholm look. Their color is dark green and leaf count is much higher than expected for trees growing in a typical urban environment.
Additional information:
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the .5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to gibneyCE.com’. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Stockholm Tree Pits
Edited by Len Phillips
Stockholm, the capital city of Sweden has developed a very successful tree planting program that many experts believe produces better tree growth than almost all the other methods (see Topic 18) developed for planting trees in downtown city sidewalks. Here is the Stockholm Tree Pits story.
Background
In 2001, Bjorn Embren was appointed to review the tree planting program in Stockholm. He began a working group including Britt-Marie Alvem, Örjan Stål, and Alf Orvesten, all well-known experts and researchers of tree roots. They also consulted with the Agricultural University of Stockholm and the University of Helsinki. They conducted a review of how trees grew in the urban environment and determined that soil conditions are most important for the establishment, development, and survival of trees in the city. They also collaborated with Klaus Schroder, a retired tree officer from Germany, who is credited with being the first person in Europe to work with structural soil.
In Stockholm center, about 20,000 street trees were dying because the city soils were lacking oxygen, water, and organic matter, plus a surplus of road salt, carbon dioxide, vehicle compaction, utility installation, and maintenance disruption were poisoning the trees.
Construction practices before 2001 required that all pavement be heavily compacted so rain water would run to the storm drains instead of the soil to discourage tree roots from growing under the pavements and causing pavement failure. Over time, the lack of water in the soils caused a decline in the trees, but more importantly, older buildings began to settle, shift, and destabilize, often requiring complete reconstruction.
In his search for answers, Mr. Embren and his team, discovered that along the railways in Stockholm, trees were growing extremely well in the stone ballast beside the tracks. The rocks in the ballast were large but stable and perhaps the same large stone could be used under the pavements in the city to allow root growth in the voids between the stones, and the stone would transfer the vehicle weight to the solid soil at the bottom of the planting pit. He also determined that the best soil conditions for trees roots surrounding the stone should consist of a homogeneous soil where the particle size distribution and humus content is mixed throughout the upper 12 inches (30 cm) of soil and the same soil minus the humus is located under this “topsoil”.
Based upon all the experts' research, and a process of trial and error, the tree planting team in the city developed a structural soil that consists of layers of 4 – 6 inch (10-15 cm) crushed rocks, installed in 10 – 12 inch (25-30 cm) thick layers. This resulted in about 25% – 30% pore space that is filled with soil. The rocks could be any available native stone, but Mr. Embren felt it would be much better to use broken up recycled concrete sidewalks instead of the native granite. Thus began an effort to plant new trees in stone filled trenches throughout the city.
Planter Construction
A deep trench or pit is dug 30 – 40 in. (0.8-1 m.) deep and rocks are placed at the bottom 24 inches (60 cm). When the first layer of stone is compacted, soil is lightly sprinkled on top of the rocks. The soil is then washed into the voids between each stone with high pressure water. The process is repeated until the voids in the rock are filled with soil. A slow-release fertilizer is sprinkled over the stone/soil mix of each layer. A second layer of stone is added on top of the previous layer and soil with humus is washed in to this layer of stone.
On the top of the compacted stone, corner pads are placed for the installation of a square precast concrete box for the tree. The bottom and holes on the side of the box are open to the compacted stone/soil mix. When the project is completed, the trees are planted in the box so the roots may grow down and into the stone/soil planting area. If the tree needs replacement, the old tree is easily removed from the concrete box and a new tree planted in the same box.
When the structural soil has reached the finished grade, a layer of finely crushed stone is laid on the top to level off the top of the stone. Geotextile fabric is laid over the entire planting pit followed by a base material for the pavement and the surface layer for the specific paving of the road, sidewalk, or bike path to be installed. The fabric prevents the pavement base material from migrating down into the planting soil mix and prevent roots from growing up into the base material.
The nutrient rich homogeneous mix of soil guarantees a good rooting space while the rock meets the bearing capacity demands for heavy traffic. The planting loam must also contain 5% – 8% humus, 4% – 8% clay, and a fertilizer based on need determined by a soil test. Mr. Embren developed structural soil combinations for the four different soil types found in the city. Each tree needs a minimum of 500 cu. ft. (15 cu. m.) and a space at least 7 ft. (2 m.) wide for small trees and 15 ft. (4 m.) wide for large trees. The length should be as long as possible to achieve a mature, healthy tree. Whenever possible the tree pits are connected together so the root space can be shared by all the trees.
Water Treatment
The whole area is also used for stormwater containment. Drainage basins sit in the top of stone/soil mix so water running off the surface pavement is able to flow down, through the stone and into the root zone of the trees. As the water flows through the stone/soil mix it is used by the trees. Any surplus water is emptied into the original storm drain for the street. The catch basins in the new construction are built with a metal screen near the bottom where oxygen can also enter the soil/stone mix. The oxygen is absorbed by the tree roots and prevents stagnation of the water. Catch basins beside the street curbs and building gutters also provide water to the tree. Fortunately, salt used on the streets in winter does not seem to cause a problem in the soil or with the tree roots because of the high volume of water flowing through the stone/soil mix.
Dealing with Trees
New trees of the right size and species to fit the planned dimensions and location should be delivered to the site and planted in the conventional manner within the concrete box. New trees are generally large, balled and burlapped, and planted directly on top of the stone base and in contact with the soil filled pores. If the existing trees are to be retained, the soil should be washed off the roots of the tree. The roots are then covered with a small size stone near the trunk, that gradually increase in size to meet the large stone installed in the trench. Soil is washed into this stone as it was in the rest of the planting trench.
Like every urban tree planting, several factors must be considered before actually planting the tree.
- Carefully select the species based on the city – Right Tree
- Trees should be planted where conditions, site location, and soils are suitable for the tree – Right Place
- Select a tree to improve local environment as well as collect and treat stormwater – Right Reason
Since the Stockholm Tree Pits program began, over 2,000 projects have been completed within the city, and the Swedish national government has accepted this concept for all future projects in the country. This program resulted in tree growth that is equal to or better than trees growing in nearby parks. It seems that all trees, regardless of species have thrived in this program. Tree experts from nurseries and other cities all remark at how well the trees in Stockholm look. Their color is dark green and leaf count is much higher than expected for trees growing in a typical urban environment.
Additional information:
- YouTube collection of photos. https://www.youtube.com/watch?v=S7kbSnnJwDI
- YouTube Lecture given by Bjorn Embren. https://www.youtube.com/watch?v=MojlKaAKeh8
- Handbook providing construction drawings and detailed information on the construction process by Bjorn Embren titled “Planting Beds in the City of Stockholm, A Handbook”, published by the City of Stockholm in 2009. This free book requires Adobe Reader and will take a couple of minutes to upload.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the .5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to gibneyCE.com’. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
What Urban Foresters Should Know About Urban Sustainability
By Shane Carpani
For the past several decades, it has become internationally recognized that the earth is unable to indefinitely support the type and extent of human activities that currently drives society. Sustainable development that ensures the healthy, lasting establishment of our local infrastructures mitigates this threat, and urban trees are essential to achieving and maintaining the sustainable environmental conditions in our cities. It is important to look at urban sustainability and examine approaches that arborists, landscape architects, urban planners, and other related professionals can consider when dealing with urban landscapes and designing cities.
Sustainable development is referred to as "development that meets the needs of present society without compromising the ability of future generations to meet their own needs," according to the World Commission on Environment and Development. It encompasses many aspects including city infrastructure, nature conservation, and much more.
At GreenBlue, we talk a lot about sustainable infrastructure because of it's importance to sustainable development. Our definition of sustainable infrastructure is the design, building, and operating of urban infrastructure in a way that does not diminish the social, economic, and ecological processes required to maintain human equity, diversity, and the functionality of natural systems.
Mature urban trees make a huge contribution to sustainable cities, but most of the trees planted each year do not survive long enough to thrive and attain effective size. Numerous factors are involved in relation to tree longevity, but the planting methods are the most important. Too often street trees are planted in cramped tree pits with poor subsoil, resulting in deficient growth.
Another major concern in considering what makes cities sustainable in a social sense, is their desirability as livable communities. Few things can compare with the visual impact and seasonal interest that trees provide. They offer immense visual appeal to any area and will enhance the design of any streetscape.
Trees have enormous appeal not only aesthetically but also for their value as utilities. Trees cool urban areas and save energy used to air condition buildings. Hence they reduce atmospheric carbon and other related complications produced by burning fossil fuels to generate electricity.
In the 21st century, the world faces tremendous challenges, including economic crises, global warming, air pollution, poverty, poor health, and loss of biodiversity. For more than two decades, sustainable development has been advanced as a means of reconciling human development with the earth’s ecological systems.
The journey toward urban sustainability has become a key goal of public policy in North America and around the world. Local governments and other authorities are increasingly incorporating Environmental Impact Assessments (EIA's) into development projects to hold developers accountable for minimizing the environmental impact of their projects.
EIA's can be undertaken for individual projects or for public plans, in order to ensure that plans likely to have significant effects on the environment are made subject to assessment prior to their approval or authorization. If the likely effects are unacceptable, design measures or other relevant mitigation procedures can be taken to reduce or avoid adverse effects.
Development that is unsustainable will eventually lead to negative environmental, social, and economic repercussions. Urban sustainability is about safeguarding the future and improving quality of life for individual countries and the global community.
Urban trees exist in strenuous constraints with many factors that negatively effect them such as soil compaction, insufficient irrigation and aeration, lack of root management, and many other issues. Urban designers and other professionals must specify appropriate urban planting systems and techniques to assure survival and adequate tree growth, in order to maintain a quality landscape and minimize the impact of climate change.
Sustainably designed trees are those that have been properly provided for so that they can not only survive in harsh urban conditions, but thrive in them. As urban landscape professionals, we can accomplish this first by
selecting trees that are drought tolerant and disease/insect resistant. We must also ensure that they have adequate volume of un-compacted soil, through the use of soil cells that provide over 90% void space for root growth with compromising structural integrity. Designing the tree pit so that ongoing access of water and nutrients can be accomplished is critical in the first years of the establishment phase. This is done through sufficient irrigation and aeration which must be done deep into the ground, and not just along the surface. Keeping tree roots in the intended rooting zones and away from utilities and paved surfaces is also critical to avoid expensive pavement damage and the likelihood of tree removal down the road. This is accomplished through the use of purpose - specific root management. For trees in public areas, it is also important to protect them above ground. We do this through the use of tree grates and vertical tree guards.
By considering these factors and applying these best practices, we can be confident in the establishment of our urban tree populations, and the predictable and dependable benefits that mature trees offer.
Shane Carpani is the Creative Director and Manager of Content Strategy at GreenBlue Infrastructure Solutions, an industry leading manufacturer of urban tree planting systems and stormwater management solutions. GreenBlue invented the world’s first soil cell in 1992 and have been helping trees thrive in urban environments ever since.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the .5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to gibneyCE.com’. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Shane Carpani
For the past several decades, it has become internationally recognized that the earth is unable to indefinitely support the type and extent of human activities that currently drives society. Sustainable development that ensures the healthy, lasting establishment of our local infrastructures mitigates this threat, and urban trees are essential to achieving and maintaining the sustainable environmental conditions in our cities. It is important to look at urban sustainability and examine approaches that arborists, landscape architects, urban planners, and other related professionals can consider when dealing with urban landscapes and designing cities.
Sustainable development is referred to as "development that meets the needs of present society without compromising the ability of future generations to meet their own needs," according to the World Commission on Environment and Development. It encompasses many aspects including city infrastructure, nature conservation, and much more.
At GreenBlue, we talk a lot about sustainable infrastructure because of it's importance to sustainable development. Our definition of sustainable infrastructure is the design, building, and operating of urban infrastructure in a way that does not diminish the social, economic, and ecological processes required to maintain human equity, diversity, and the functionality of natural systems.
Mature urban trees make a huge contribution to sustainable cities, but most of the trees planted each year do not survive long enough to thrive and attain effective size. Numerous factors are involved in relation to tree longevity, but the planting methods are the most important. Too often street trees are planted in cramped tree pits with poor subsoil, resulting in deficient growth.
Another major concern in considering what makes cities sustainable in a social sense, is their desirability as livable communities. Few things can compare with the visual impact and seasonal interest that trees provide. They offer immense visual appeal to any area and will enhance the design of any streetscape.
Trees have enormous appeal not only aesthetically but also for their value as utilities. Trees cool urban areas and save energy used to air condition buildings. Hence they reduce atmospheric carbon and other related complications produced by burning fossil fuels to generate electricity.
In the 21st century, the world faces tremendous challenges, including economic crises, global warming, air pollution, poverty, poor health, and loss of biodiversity. For more than two decades, sustainable development has been advanced as a means of reconciling human development with the earth’s ecological systems.
The journey toward urban sustainability has become a key goal of public policy in North America and around the world. Local governments and other authorities are increasingly incorporating Environmental Impact Assessments (EIA's) into development projects to hold developers accountable for minimizing the environmental impact of their projects.
EIA's can be undertaken for individual projects or for public plans, in order to ensure that plans likely to have significant effects on the environment are made subject to assessment prior to their approval or authorization. If the likely effects are unacceptable, design measures or other relevant mitigation procedures can be taken to reduce or avoid adverse effects.
Development that is unsustainable will eventually lead to negative environmental, social, and economic repercussions. Urban sustainability is about safeguarding the future and improving quality of life for individual countries and the global community.
Urban trees exist in strenuous constraints with many factors that negatively effect them such as soil compaction, insufficient irrigation and aeration, lack of root management, and many other issues. Urban designers and other professionals must specify appropriate urban planting systems and techniques to assure survival and adequate tree growth, in order to maintain a quality landscape and minimize the impact of climate change.
Sustainably designed trees are those that have been properly provided for so that they can not only survive in harsh urban conditions, but thrive in them. As urban landscape professionals, we can accomplish this first by
selecting trees that are drought tolerant and disease/insect resistant. We must also ensure that they have adequate volume of un-compacted soil, through the use of soil cells that provide over 90% void space for root growth with compromising structural integrity. Designing the tree pit so that ongoing access of water and nutrients can be accomplished is critical in the first years of the establishment phase. This is done through sufficient irrigation and aeration which must be done deep into the ground, and not just along the surface. Keeping tree roots in the intended rooting zones and away from utilities and paved surfaces is also critical to avoid expensive pavement damage and the likelihood of tree removal down the road. This is accomplished through the use of purpose - specific root management. For trees in public areas, it is also important to protect them above ground. We do this through the use of tree grates and vertical tree guards.
By considering these factors and applying these best practices, we can be confident in the establishment of our urban tree populations, and the predictable and dependable benefits that mature trees offer.
Shane Carpani is the Creative Director and Manager of Content Strategy at GreenBlue Infrastructure Solutions, an industry leading manufacturer of urban tree planting systems and stormwater management solutions. GreenBlue invented the world’s first soil cell in 1992 and have been helping trees thrive in urban environments ever since.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the .5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to gibneyCE.com’. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Tree of the Seminar
By Len Phillips
Japanese Stewartia features a kaleidoscope of fall color including red, orange and purple tones. Its beautiful cream and tan patches are revealed as its trunk exfoliates with age. 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.
Trade Name: Japanese Stewartia
Botanical Name: Stewartia pseudocamellia
Family: Theaceae
Parentage: Introduction into the US from Japan
Introduction: 1874
Hardiness Zone: 4 – 7
Height: 20' – 40', sometimes to 60' feet high
Spread: 20' – 25'
Growth Rate: Slow to medium, 5' in 10 years
Form: Pyramidal to oval
Bloom Period: July
Flower: White with orange anthers, Camellia-like white flowers up to 2 ½" in diameter
Fruit: A 1” long, pubescent, seed
Summer Foliage: Medium to dark green in summer
Autumn Foliage: Orange, yellow, red, purple
Winter Interest: Bark provides winter and year-round interest
Bark: Exfoliating cream and tan patches
Habitat: Grows well throughout the hardiness range
Culture: Prefers moist,acidic soil with plenty of organic matter, full to partial sun
Pest Problems: None
Storm Resistance: Good
Salt Tolerance: Fair
Planting: Only transplant small trees (4'-5' tall) B&B or by container in the spring
Pruning: Seldom needed
Propagating: Softwood cutting only, difficult rooting process
Design Uses: Specimen for lawn, park, and residential landscapes
Companions: None, best grown by itself to minimize competition for soil and nutrients
Other Comments: Excellent tree for special locations, should be in a location visible to pedestrians
Photo: J. Frank Schmidt & Son
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the .5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to gibneyCE.com’. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Len Phillips
Japanese Stewartia features a kaleidoscope of fall color including red, orange and purple tones. Its beautiful cream and tan patches are revealed as its trunk exfoliates with age. 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.
Trade Name: Japanese Stewartia
Botanical Name: Stewartia pseudocamellia
Family: Theaceae
Parentage: Introduction into the US from Japan
Introduction: 1874
Hardiness Zone: 4 – 7
Height: 20' – 40', sometimes to 60' feet high
Spread: 20' – 25'
Growth Rate: Slow to medium, 5' in 10 years
Form: Pyramidal to oval
Bloom Period: July
Flower: White with orange anthers, Camellia-like white flowers up to 2 ½" in diameter
Fruit: A 1” long, pubescent, seed
Summer Foliage: Medium to dark green in summer
Autumn Foliage: Orange, yellow, red, purple
Winter Interest: Bark provides winter and year-round interest
Bark: Exfoliating cream and tan patches
Habitat: Grows well throughout the hardiness range
Culture: Prefers moist,acidic soil with plenty of organic matter, full to partial sun
Pest Problems: None
Storm Resistance: Good
Salt Tolerance: Fair
Planting: Only transplant small trees (4'-5' tall) B&B or by container in the spring
Pruning: Seldom needed
Propagating: Softwood cutting only, difficult rooting process
Design Uses: Specimen for lawn, park, and residential landscapes
Companions: None, best grown by itself to minimize competition for soil and nutrients
Other Comments: Excellent tree for special locations, should be in a location visible to pedestrians
Photo: J. Frank Schmidt & Son
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the .5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to gibneyCE.com’. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Trees in American History
Edited by Len Phillips
When settlers came to America, they were greeted with vast forests of large trees. These trees were used for paper, building ships, keeping warm, and eventually building homes, fortresses, and fences. The tall and straight Eastern White Pine (Pinus strobus) trees were claimed by the British King for the sailing masts on the ships in the Royal Navy.
The Pine Tree
At the same time the early settlers honored the pine tree. The first coin in the colonies was the pine tree shilling which had an image of the pine on one side of the coin. Willows (Salix) were another frequently used tree as a symbol in the colonies. Certain trees were also used by native Americans and early settlers as trail markers for guiding travelers from one village to the next.
A Fruit Tree
Another early use of trees in the colonies was to provide food. Among the first wave of immigrants to the New World was an English Puritan named John Endecott, who in 1629, arrived to serve as the first governor of the Massachusetts Bay Colony. In 1630, as his children watched, Endicott planted a pear tree imported from across the Atlantic. He is said to have declared at the time: "I hope the tree will love the soil and when we have gone the tree will still be alive." This 385 year old pear tree is still alive in present day Danvers, Massachusetts. It lives on the former Endicott farm and is now surrounded by an iron fence and is tended every year by a local arborist. The tree is also still bearing fruit every year.
Importance of Trees
Many settlers held religious services beneath the branches of stately trees. One tree, on a hilltop in Natick, Massachusetts was used for church services for over 50 years as well as a location for fostering debates focused on independence from England. William Penn declared one acre out of five should be spared of clearing the trees in Philadelphia.
On December 2, 1633 the Town of Cambridge, Massachusetts issued an order that any person who fell any tree near the path between Watertown and Charlestown, going through Cambridge would be fined five shillings for every tree felled. In 1635, Boston on the other hand, ordered all the trees removed from the neck connecting the city to the mainland. The wood was used for building lumber and fuel. This also eliminated the forest cover that provided hiding places for robbers who ambushed travelers. By 1646 however, Bostonians realized that the loss of the forest caused floods, erosion, and no shelter from the intense summer heat. The first public shade tree planting in the New World occurred that spring when a large number of men planted American elms. The children carried water to the trees while the women and maidens prepared the food.
Historic Trees
There were several trees that became very important in early American history. One massive oak tree in Connecticut was called the Charter Oak because it was used to hide Connecticut's charter when agents of the Crown were looking to revoke it in 1687. The tree fell during a storm in 1856 but it is still found in Connecticut iconography including a 3 cent U.S. postage stamp from 1935 to celebrate Connecticut's tercentenary and on a U.S. coin, a quarter issued in 1999 in honor of the state.
Another tree called the Liberty Tree was a large and impressive elm on the road leading in and out of Boston. It was under this tree that colonists gathered to protest the hated taxes imposed by the King. The tree became a symbol of civil disobedience in 1765. Many tax collectors were tar and feathered or hung in effigies along with messages of protest hanging from the branches of this tree. This tree was also called the Crucible of Revolution and was written about by Thomas Paine and Thomas Jefferson, along with several other patriots of the time. Some of the British loyalists were very upset by the signs and messages posted in this tree and in 1774 the British army cut the tree down. However, after this tree was destroyed, the backlash was swift. Bostonians quickly found another tree to meet under. Throughout the Colonies, trees were named in each capital city as an official Liberty Tree and many other cities and towns also selected their own local Liberty trees. These local trees were not necessarily an old or special tree, although that was often the case.
Incidentally, in 1999, in Annapolis, MD, the last of the 13 surviving Liberty Trees was severely damaged by Hurricane Floyd. A low lateral limb was twisted and ripped open the 8.5 ft. (2.6 m) diameter trunk, which was already very hollow, except for a 6 ft.(1.8 m) diameter core of concrete and stone. After an extensive review by a number of top arborists, it was decided to remove the last named survivor of the colonial Liberty Trees. It was removed with a lot of press and fanfare, more than 400 people attended a public event. A seedling from this tree, now already about 170 years old, stands just a short distance from the historic site.
Tall Pines
Trees were not used just for sentimental purposes, they were also used as an important export to Europe, especially the white pine which often grew to 150 feet tall and was the perfect mast for sailing ships. In 1772, the Pine Tree Riot occurred in New Hampshire. The King of England was claiming all pines larger than a 12 inch diameter belonged to the Royal Navy. Land owners could not sell or cut down these trees. This Riot was one of the first signs of the Revolution that began four years later. The colonists then began using tree images as a symbol of their resistance. They sewed images of trees onto their flags and carved them into their gunpowder horns and gathered under trees to discuss their grievances against the Crown and to develop plans to revolt. In 1776 when George Washington took command of the American Army, he did so under a spreading elm on the Cambridge, MA Town Common.
After the Declaration of Independence was signed in 1776, the selling of tall pines to England was stopped and the pines were then used on the American Navy ships. As a result, the British Navy's aging and battle fatigued masts were easily broken and this greatly impacted the outcome of naval battles throughout the Revolutionary War. During the 1783 battle of Yorktown, the final battle of the Revolution, the faulty masts prevented the British Navy from sending a large fleet of ships to reinforce the army of General Cornwallis. So the tall pines helped win the war that they had inspired in 1765.
Tree Lovers
After the Revolution, trees continued to play an important role in American life. Several presidents were considered tree-lovers. George Washington was obsessed with trees at Mount Vernon. Thomas Jefferson was a very progressive horticulturalist and read many books about trees. He also recorded information about a lot of tree species he planted at Monticello, his estate in Virginia. The president who created the greatest number of national forests was Theodore Roosevelt. He was profoundly shaped by the wilderness, nature, and forests west of the Mississippi River. Franklin D. Roosevelt loved trees and encouraged the planting of 3 billion trees by the Civilian Conservation Corps and other work projects he created during the recovery efforts from the Great Depression. When FDR was the president he considered his occupation to be a “tree grower.”
For most of American history, cities were small and surrounded by trees. Early town centers had a common where cattle grazed and trees were grown to provide relief from the summer heat. Most residents depended on wood to build many things. The 18th century was a time when we were chopping down trees and planting almost none to replace them. That trend changed over the course of the 19th century when more trees were being planted than being cut down. At the same time new legislation was creating things like wilderness areas, recreation in forests, and national parks.
Johnny Appleseed is a legend based on the life of John Chapman who lived in the Midwest from 1774 – 1845. Legend says he planted apple seeds everywhere he went throughout six states so when early settlers arrived, apple trees were waiting for them. The fact is that he planted many nurseries rather than orchards and built fences around them to protect them from livestock. He then left the nursery in the care of a neighbor who sold trees on shares and Johnny returned every year or two to tend the nursery. At the time of his death, Johnny had over 1,200 acres of nursery land containing thousands of trees.
Recent Tree Events
In recent history there have been two “Survivor Trees”. In Oklahoma City, a terrorist's bomb destroyed the Murrah Federal Building and one of the few things left standing was a badly damaged, but alive American elm. At the Twin Towers in New York City, a callery pear managed to survive the loss of the two buildings. Both trees have been preserved and have become symbols of American resilience.
Today, Americans are still recognizing trees for their value. The United States is home to the world's biggest tree (General Sherman growing in Sequoia National Park in California), the world's tallest tree (Hyperion, a Coastal Redwood in northern California), and the world's oldest trees. The oldest and biggest single organism on earth is a stand of quaking aspens in Utah, known as the "Trembling Giant" or Pando. It is the clonal colony of a single male quaking aspen (Populus tremuloides) which has been determined to be a single living organism by identical genetic markers and assumed to have one massive underground root system. The plant is estimated to weigh collectively 6,600 tons (6,000 metric tons), making it the heaviest known organism. The root system of Pando is estimated to be 80,000 years old and has lived through many wildfires. After each fire, the root system sends up new trees to replace those lost.
Since 1940, the National Big Tree Program has been preserving and promoting the living monarchs to educate people about the key role that these trees play in sustaining a healthy environment. More than 750 champions are crowned and documented in the Champion Trees National Register.
Celebrations
Finally, there are two tree celebrations that are found throughout America. One is the annual Arbor Day program and the other is the Christmas tree.
1. Arbor Day – was founded in 1872 by Julius Sterling Morton in Nebraska City, Nebraska. By the 1920s, every state had passed public laws that stipulated a certain day to be Arbor Day. National Arbor Day is celebrated every year, ususally on the last Friday in April, while in Nebraska, it is a civic holiday. The customary Arbor Day ceremony includes the planting of a tree. On the first Arbor Day, April 10, 1872, an estimated one million trees were planted.
2. Christmas Tree – The Puritan influence in New England led to laws making any Christmas observance of December 25, other than attending a church service, a penal offense and people were fined for hanging decorations. These laws continued until the mid-1800's when the German and Irish immigrants undermined the Puritan legacy. In 1846 the very popular Queen Victoria was shown standing with their children around a Christmas tree. The Christmas tree immediately became fashionable in Britain as well as the fashion-conscious East Coast American society. Since the 1850's, decorating Christmas trees at the White House has been an annual event, except when Teddy Roosevelt banned the White House tree for environmental reasons.
Sources
Note from the Editor: If there are significant or historic trees in your region, send me a message so I can honor them in the next Seminar.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the .5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, Aerial Lift Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to gibneyCE.com’. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
When settlers came to America, they were greeted with vast forests of large trees. These trees were used for paper, building ships, keeping warm, and eventually building homes, fortresses, and fences. The tall and straight Eastern White Pine (Pinus strobus) trees were claimed by the British King for the sailing masts on the ships in the Royal Navy.
The Pine Tree
At the same time the early settlers honored the pine tree. The first coin in the colonies was the pine tree shilling which had an image of the pine on one side of the coin. Willows (Salix) were another frequently used tree as a symbol in the colonies. Certain trees were also used by native Americans and early settlers as trail markers for guiding travelers from one village to the next.
A Fruit Tree
Another early use of trees in the colonies was to provide food. Among the first wave of immigrants to the New World was an English Puritan named John Endecott, who in 1629, arrived to serve as the first governor of the Massachusetts Bay Colony. In 1630, as his children watched, Endicott planted a pear tree imported from across the Atlantic. He is said to have declared at the time: "I hope the tree will love the soil and when we have gone the tree will still be alive." This 385 year old pear tree is still alive in present day Danvers, Massachusetts. It lives on the former Endicott farm and is now surrounded by an iron fence and is tended every year by a local arborist. The tree is also still bearing fruit every year.
Importance of Trees
Many settlers held religious services beneath the branches of stately trees. One tree, on a hilltop in Natick, Massachusetts was used for church services for over 50 years as well as a location for fostering debates focused on independence from England. William Penn declared one acre out of five should be spared of clearing the trees in Philadelphia.
On December 2, 1633 the Town of Cambridge, Massachusetts issued an order that any person who fell any tree near the path between Watertown and Charlestown, going through Cambridge would be fined five shillings for every tree felled. In 1635, Boston on the other hand, ordered all the trees removed from the neck connecting the city to the mainland. The wood was used for building lumber and fuel. This also eliminated the forest cover that provided hiding places for robbers who ambushed travelers. By 1646 however, Bostonians realized that the loss of the forest caused floods, erosion, and no shelter from the intense summer heat. The first public shade tree planting in the New World occurred that spring when a large number of men planted American elms. The children carried water to the trees while the women and maidens prepared the food.
Historic Trees
There were several trees that became very important in early American history. One massive oak tree in Connecticut was called the Charter Oak because it was used to hide Connecticut's charter when agents of the Crown were looking to revoke it in 1687. The tree fell during a storm in 1856 but it is still found in Connecticut iconography including a 3 cent U.S. postage stamp from 1935 to celebrate Connecticut's tercentenary and on a U.S. coin, a quarter issued in 1999 in honor of the state.
Another tree called the Liberty Tree was a large and impressive elm on the road leading in and out of Boston. It was under this tree that colonists gathered to protest the hated taxes imposed by the King. The tree became a symbol of civil disobedience in 1765. Many tax collectors were tar and feathered or hung in effigies along with messages of protest hanging from the branches of this tree. This tree was also called the Crucible of Revolution and was written about by Thomas Paine and Thomas Jefferson, along with several other patriots of the time. Some of the British loyalists were very upset by the signs and messages posted in this tree and in 1774 the British army cut the tree down. However, after this tree was destroyed, the backlash was swift. Bostonians quickly found another tree to meet under. Throughout the Colonies, trees were named in each capital city as an official Liberty Tree and many other cities and towns also selected their own local Liberty trees. These local trees were not necessarily an old or special tree, although that was often the case.
,_The_Bostonians_Paying_the_Excise-man,_or_Tarring_and_Feathering_(1774)_-_02.jpg){kind=link}
Incidentally, in 1999, in Annapolis, MD, the last of the 13 surviving Liberty Trees was severely damaged by Hurricane Floyd. A low lateral limb was twisted and ripped open the 8.5 ft. (2.6 m) diameter trunk, which was already very hollow, except for a 6 ft.(1.8 m) diameter core of concrete and stone. After an extensive review by a number of top arborists, it was decided to remove the last named survivor of the colonial Liberty Trees. It was removed with a lot of press and fanfare, more than 400 people attended a public event. A seedling from this tree, now already about 170 years old, stands just a short distance from the historic site.
Tall Pines
Trees were not used just for sentimental purposes, they were also used as an important export to Europe, especially the white pine which often grew to 150 feet tall and was the perfect mast for sailing ships. In 1772, the Pine Tree Riot occurred in New Hampshire. The King of England was claiming all pines larger than a 12 inch diameter belonged to the Royal Navy. Land owners could not sell or cut down these trees. This Riot was one of the first signs of the Revolution that began four years later. The colonists then began using tree images as a symbol of their resistance. They sewed images of trees onto their flags and carved them into their gunpowder horns and gathered under trees to discuss their grievances against the Crown and to develop plans to revolt. In 1776 when George Washington took command of the American Army, he did so under a spreading elm on the Cambridge, MA Town Common.
After the Declaration of Independence was signed in 1776, the selling of tall pines to England was stopped and the pines were then used on the American Navy ships. As a result, the British Navy's aging and battle fatigued masts were easily broken and this greatly impacted the outcome of naval battles throughout the Revolutionary War. During the 1783 battle of Yorktown, the final battle of the Revolution, the faulty masts prevented the British Navy from sending a large fleet of ships to reinforce the army of General Cornwallis. So the tall pines helped win the war that they had inspired in 1765.
Tree Lovers
After the Revolution, trees continued to play an important role in American life. Several presidents were considered tree-lovers. George Washington was obsessed with trees at Mount Vernon. Thomas Jefferson was a very progressive horticulturalist and read many books about trees. He also recorded information about a lot of tree species he planted at Monticello, his estate in Virginia. The president who created the greatest number of national forests was Theodore Roosevelt. He was profoundly shaped by the wilderness, nature, and forests west of the Mississippi River. Franklin D. Roosevelt loved trees and encouraged the planting of 3 billion trees by the Civilian Conservation Corps and other work projects he created during the recovery efforts from the Great Depression. When FDR was the president he considered his occupation to be a “tree grower.”
For most of American history, cities were small and surrounded by trees. Early town centers had a common where cattle grazed and trees were grown to provide relief from the summer heat. Most residents depended on wood to build many things. The 18th century was a time when we were chopping down trees and planting almost none to replace them. That trend changed over the course of the 19th century when more trees were being planted than being cut down. At the same time new legislation was creating things like wilderness areas, recreation in forests, and national parks.
Johnny Appleseed is a legend based on the life of John Chapman who lived in the Midwest from 1774 – 1845. Legend says he planted apple seeds everywhere he went throughout six states so when early settlers arrived, apple trees were waiting for them. The fact is that he planted many nurseries rather than orchards and built fences around them to protect them from livestock. He then left the nursery in the care of a neighbor who sold trees on shares and Johnny returned every year or two to tend the nursery. At the time of his death, Johnny had over 1,200 acres of nursery land containing thousands of trees.
Recent Tree Events
In recent history there have been two “Survivor Trees”. In Oklahoma City, a terrorist's bomb destroyed the Murrah Federal Building and one of the few things left standing was a badly damaged, but alive American elm. At the Twin Towers in New York City, a callery pear managed to survive the loss of the two buildings. Both trees have been preserved and have become symbols of American resilience.
Today, Americans are still recognizing trees for their value. The United States is home to the world's biggest tree (General Sherman growing in Sequoia National Park in California), the world's tallest tree (Hyperion, a Coastal Redwood in northern California), and the world's oldest trees. The oldest and biggest single organism on earth is a stand of quaking aspens in Utah, known as the "Trembling Giant" or Pando. It is the clonal colony of a single male quaking aspen (Populus tremuloides) which has been determined to be a single living organism by identical genetic markers and assumed to have one massive underground root system. The plant is estimated to weigh collectively 6,600 tons (6,000 metric tons), making it the heaviest known organism. The root system of Pando is estimated to be 80,000 years old and has lived through many wildfires. After each fire, the root system sends up new trees to replace those lost.
Since 1940, the National Big Tree Program has been preserving and promoting the living monarchs to educate people about the key role that these trees play in sustaining a healthy environment. More than 750 champions are crowned and documented in the Champion Trees National Register.
Celebrations
Finally, there are two tree celebrations that are found throughout America. One is the annual Arbor Day program and the other is the Christmas tree.
1. Arbor Day – was founded in 1872 by Julius Sterling Morton in Nebraska City, Nebraska. By the 1920s, every state had passed public laws that stipulated a certain day to be Arbor Day. National Arbor Day is celebrated every year, ususally on the last Friday in April, while in Nebraska, it is a civic holiday. The customary Arbor Day ceremony includes the planting of a tree. On the first Arbor Day, April 10, 1872, an estimated one million trees were planted.
2. Christmas Tree – The Puritan influence in New England led to laws making any Christmas observance of December 25, other than attending a church service, a penal offense and people were fined for hanging decorations. These laws continued until the mid-1800's when the German and Irish immigrants undermined the Puritan legacy. In 1846 the very popular Queen Victoria was shown standing with their children around a Christmas tree. The Christmas tree immediately became fashionable in Britain as well as the fashion-conscious East Coast American society. Since the 1850's, decorating Christmas trees at the White House has been an annual event, except when Teddy Roosevelt banned the White House tree for environmental reasons.
Sources
- American Forests, Website at americanforests.org 2015.
- Carlson, Russ, Liberty Tree assessment and report
- Crawford, Amy, “How trees defined America”, Smithsonian, June 13, 2012.
- History Channel, “The History of Christmas Trees”, 2015.
- Widmer, Ted, “The indelible symbolism of a tree”, Boston Globe, November 22, 2015.
Note from the Editor: If there are significant or historic trees in your region, send me a message so I can honor them in the next Seminar.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the .5 CEUs toward Certified Arborist, Municipal Specialist, Tree Worker Specialist, Aerial Lift Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to gibneyCE.com’. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
UtiliTrees™ – Two
Edited by Len Phillips
Several Seminars ago, Nancy Buley wrote an article describing nine trees that are suitable for growing under a city’s utility lines. Frequent requests for advice on the best trees to plant in this challenging zone led J. Frank Schmidt & Son Co. to develop a list of preferred trees branded as UtiliTrees™. Launched more than 20 years ago, the list has been expanded over the years to include nearly 50 time-tested trees that perform well in many growing regions of the US, Canada, and beyond. Urban foresters, utility arborists, landscape architects and other specifiers have embraced the list and have customized it to suit their own unique local growing conditions.
This list of trees are well suited for planting in the restricted zone between the street and sidewalk and beneath the utility lines. All these trees mature at heights that are unlikely to tangle with overhead lines. These trees are also considered pedestrian friendly because their branching is compact or vase-shaped which allows for pruning without destroying the shape of the trees. Disease and pest resistant, these cultivars are tolerant of varied soils, climates, and urban growing conditions and require minimal maintenance.
Here is a list of trees that were discussed in Seminar #51. Paperbark Maple, Rugged Charm® Maple, Spring Flurry® Serviceberry, Crushed Velvet™ Silverbell, Pink Flair® Cherry, Jack® Pear, Ivory Silk Japanese Tree Lilac, City Sprite® Zelkova, and Wireless® Zelkova.
This list and the trees that follow are a great starting point for cities seeking to develop their own list of recommended trees. Several favorites, plus some newer additions are described. This link leads to the entire UtiliTree list and shows height, spread, and form at a glance. The ten trees that follow are on the UtiliTree list and are described here for those who are interested in making your own list of UtiliTrees. The photos for each may be downloaded by clicking on the word, “Photo”.
Hedge Maple Acer campestre – Zone: 5; Height: 30’; Spread: 30’; Shape: dense and rounded; Foliage: glossy and dark green; Fall Color: yellowish; Insect resistance: Japanese beetle.
A low maintenance, tough tree which adapts well to urban settings. Medium to slow growth rate and long lived. The attractive corky bark is striking in the winter. Photo
Flame Maple Acer ginnala ‘Flame’ – Zone: 2; Height: 20’; Spread: 20’; Shape: a rounded, low branched or multi-stemmed tree; Foliage: fine textured and medium green; Fall Color: brilliant orange red to deep red.
One of the hardiest trees available. Specimens are very interesting in form because of their spreading branch pattern. Flame is a seed source selection, chosen for improved form and consistent fall color. Photo
Autumn Brilliance Serviceberry Amelanchier x grandiflora ‘Autumn Brilliance’ Zone: 4; Height: 20'; Spread: 15'; Shape: upright and moderately spreading; Foliage: green medium; Fall Color: bright red; Flower: clusters of white; Fruit: purplish blue and edible, 1⁄4” in diameter.
An excellent Amelanchier with good form and strong branching. It displays reliable spring bloom and bright fall colors. Photo
Cole’s Select Serviceberry Amelanchier × grandiflora ‘Cole’s Select’ – Zone: 4; Height: 20’; Spread: 15’; Shape: upright and spreading; Foliage: small and green; Fall Color: bright orange-red; Flower: white clusters; Fruit: edible and purplish blue, 1⁄4” in diameter.
This Amelanchier selection has thicker, glossier foliage than the others, giving it a healthy appearance in midsummer. Photo
Crimson Cloud Hawthorn Crataegus laevigata ‘Crimson Cloud’ – Zone: 4; Height: 25'; Spread: 18'; Shape: oval with upright spreading wavy branches; Foliage: small and glossy green; Flower: bright red with white centers; Fruit: bright red; Disease resistance: leaf spot.
This tree is distinctive for its wavy branch habit and bright red flowers with white centers. Photo
Washington Hawthorn Crataegus phaenopyrum – Zone: 4; Height: 25’; Spread: 20’; Shape: broadly oval to rounded; Foliage: deep green and very glossy; Fall Color: orange to scarlet and reddish purple; Flower: white clusters; Fruit: persistent bright and glossy red, 1⁄4” in diameter.
The small attractive fruits blend beautifully with the autumn leaves. Many people rate this the best North American Hawthorn. Very useful in both multi-stem and tree form. Photo
Adirondack Crabapple Malus ‘Adirondack’ – Zone: 4; Height: 18’; Spread: 10’; Shape: densely upright inverted cone; Foliage: medium green; Flower: white; Fruit: bright red, 1⁄2” in diameter; Disease resistance: Scab: excellent, Fireblight: excellent, Cedar-Apple Rust: excellent, Mildew: excellent,
Adirondack is an important cultivar because of its form and outstanding flower display. It is a compact, dense tree with strongly upright form. It produces one of the heaviest flower displays of the crabs. A National Arboretum introduction. Photo
Golden Raindrops Crabapple Malus ‘Schmidtcutleaf’ – Zone: 3; Height: 20'; Spread: 15'; Shape: upright to vase shaped; Foliage: green and deeply cut; Flower: white; Fruit: Golden yellow, 1⁄4" in diameter; Disease resistance: Scab: excellent, Fireblight: poor, Cedar-Apple Rust: excellent, Mildew: excellent.
Fine textured, deeply cut foliage gives this unusual crab a delicate appearance. The form is elegant, with slender limbs spreading horizontally from upright branches. The abundant golden yellow fruit is truly tiny. Photo
Big Cis® Plum Prunus x cistena ‘Schmidtcis’ – Zone: 4; Height: 14'; Spread: 12'; Shape: rounded and dense; Foliage: Purple; Flower: light pink and very fragrant.
A sport of P. cistena, Big Cis® Plum grows quickly to a heavy-trunked, sturdy tree that is intermediate in size between Cistena and Newport. Cistena-like flowers are followed by dark purple foliage that keeps its fresh, clean appearance later in the season. Photo
Crimson Pointe Plum Prunus cerasifera ‘Cripoizam’ – Zone: 4; Height: 25’; Spread: 10’; Shape: columnar to narrow oval; Foliage: purple red to purple bronze; Fall Color: reddish; Flower: pink buds and white flowers; Fruit: purple, 1" in diameter.
Pink buds open to white flowers that contrast nicely with the emerging purple foliage. This columnar selection develops a narrowly oval mature canopy. A strong central leader and a fast growth rate make it easy to grow in the city. Photo
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the .5 CEUs toward Certified Arborist, Utility Specialist, Municipal Specialist, Tree Worker Specialist, Aerial Lift Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to 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
Several Seminars ago, Nancy Buley wrote an article describing nine trees that are suitable for growing under a city’s utility lines. Frequent requests for advice on the best trees to plant in this challenging zone led J. Frank Schmidt & Son Co. to develop a list of preferred trees branded as UtiliTrees™. Launched more than 20 years ago, the list has been expanded over the years to include nearly 50 time-tested trees that perform well in many growing regions of the US, Canada, and beyond. Urban foresters, utility arborists, landscape architects and other specifiers have embraced the list and have customized it to suit their own unique local growing conditions.
This list of trees are well suited for planting in the restricted zone between the street and sidewalk and beneath the utility lines. All these trees mature at heights that are unlikely to tangle with overhead lines. These trees are also considered pedestrian friendly because their branching is compact or vase-shaped which allows for pruning without destroying the shape of the trees. Disease and pest resistant, these cultivars are tolerant of varied soils, climates, and urban growing conditions and require minimal maintenance.
Here is a list of trees that were discussed in Seminar #51. Paperbark Maple, Rugged Charm® Maple, Spring Flurry® Serviceberry, Crushed Velvet™ Silverbell, Pink Flair® Cherry, Jack® Pear, Ivory Silk Japanese Tree Lilac, City Sprite® Zelkova, and Wireless® Zelkova.
This list and the trees that follow are a great starting point for cities seeking to develop their own list of recommended trees. Several favorites, plus some newer additions are described. This link leads to the entire UtiliTree list and shows height, spread, and form at a glance. The ten trees that follow are on the UtiliTree list and are described here for those who are interested in making your own list of UtiliTrees. The photos for each may be downloaded by clicking on the word, “Photo”.
Hedge Maple Acer campestre – Zone: 5; Height: 30’; Spread: 30’; Shape: dense and rounded; Foliage: glossy and dark green; Fall Color: yellowish; Insect resistance: Japanese beetle.
A low maintenance, tough tree which adapts well to urban settings. Medium to slow growth rate and long lived. The attractive corky bark is striking in the winter. Photo
Flame Maple Acer ginnala ‘Flame’ – Zone: 2; Height: 20’; Spread: 20’; Shape: a rounded, low branched or multi-stemmed tree; Foliage: fine textured and medium green; Fall Color: brilliant orange red to deep red.
One of the hardiest trees available. Specimens are very interesting in form because of their spreading branch pattern. Flame is a seed source selection, chosen for improved form and consistent fall color. Photo
Autumn Brilliance Serviceberry Amelanchier x grandiflora ‘Autumn Brilliance’ Zone: 4; Height: 20'; Spread: 15'; Shape: upright and moderately spreading; Foliage: green medium; Fall Color: bright red; Flower: clusters of white; Fruit: purplish blue and edible, 1⁄4” in diameter.
An excellent Amelanchier with good form and strong branching. It displays reliable spring bloom and bright fall colors. Photo
Cole’s Select Serviceberry Amelanchier × grandiflora ‘Cole’s Select’ – Zone: 4; Height: 20’; Spread: 15’; Shape: upright and spreading; Foliage: small and green; Fall Color: bright orange-red; Flower: white clusters; Fruit: edible and purplish blue, 1⁄4” in diameter.
This Amelanchier selection has thicker, glossier foliage than the others, giving it a healthy appearance in midsummer. Photo
Crimson Cloud Hawthorn Crataegus laevigata ‘Crimson Cloud’ – Zone: 4; Height: 25'; Spread: 18'; Shape: oval with upright spreading wavy branches; Foliage: small and glossy green; Flower: bright red with white centers; Fruit: bright red; Disease resistance: leaf spot.
This tree is distinctive for its wavy branch habit and bright red flowers with white centers. Photo
Washington Hawthorn Crataegus phaenopyrum – Zone: 4; Height: 25’; Spread: 20’; Shape: broadly oval to rounded; Foliage: deep green and very glossy; Fall Color: orange to scarlet and reddish purple; Flower: white clusters; Fruit: persistent bright and glossy red, 1⁄4” in diameter.
The small attractive fruits blend beautifully with the autumn leaves. Many people rate this the best North American Hawthorn. Very useful in both multi-stem and tree form. Photo
Adirondack Crabapple Malus ‘Adirondack’ – Zone: 4; Height: 18’; Spread: 10’; Shape: densely upright inverted cone; Foliage: medium green; Flower: white; Fruit: bright red, 1⁄2” in diameter; Disease resistance: Scab: excellent, Fireblight: excellent, Cedar-Apple Rust: excellent, Mildew: excellent,
Adirondack is an important cultivar because of its form and outstanding flower display. It is a compact, dense tree with strongly upright form. It produces one of the heaviest flower displays of the crabs. A National Arboretum introduction. Photo
Golden Raindrops Crabapple Malus ‘Schmidtcutleaf’ – Zone: 3; Height: 20'; Spread: 15'; Shape: upright to vase shaped; Foliage: green and deeply cut; Flower: white; Fruit: Golden yellow, 1⁄4" in diameter; Disease resistance: Scab: excellent, Fireblight: poor, Cedar-Apple Rust: excellent, Mildew: excellent.
Fine textured, deeply cut foliage gives this unusual crab a delicate appearance. The form is elegant, with slender limbs spreading horizontally from upright branches. The abundant golden yellow fruit is truly tiny. Photo
Big Cis® Plum Prunus x cistena ‘Schmidtcis’ – Zone: 4; Height: 14'; Spread: 12'; Shape: rounded and dense; Foliage: Purple; Flower: light pink and very fragrant.
A sport of P. cistena, Big Cis® Plum grows quickly to a heavy-trunked, sturdy tree that is intermediate in size between Cistena and Newport. Cistena-like flowers are followed by dark purple foliage that keeps its fresh, clean appearance later in the season. Photo
Crimson Pointe Plum Prunus cerasifera ‘Cripoizam’ – Zone: 4; Height: 25’; Spread: 10’; Shape: columnar to narrow oval; Foliage: purple red to purple bronze; Fall Color: reddish; Flower: pink buds and white flowers; Fruit: purple, 1" in diameter.
Pink buds open to white flowers that contrast nicely with the emerging purple foliage. This columnar selection develops a narrowly oval mature canopy. A strong central leader and a fast growth rate make it easy to grow in the city. Photo
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the .5 CEUs toward Certified Arborist, Utility Specialist, Municipal Specialist, Tree Worker Specialist, Aerial Lift Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to 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.
Bacterial Leaf Scorch
Edited by Len Phillips
This disease is actually spread by insects and unfortunately no good cure is available.
Common Name: Bacterial Leaf Scorch (BLS)
Pathogen: BLS is spread by a xylem-limited bacterium Xylella fastidiosa.
Common Causes: This bacterium causes decline and death of many herbaceous and woody plant hosts due to restriction of water flow from the roots to the crown of the plant.
Location: BLS is established in almost all warm areas of the US as far north as New Jersey, through the south, west to Texas, and in California. There has also been confirmation of the disease occurring in Illinois.
Introduction: This pathogen was first discovered in grapes and causes Pierce's Disease. BLS is a newly recognized disease and many researchers are currently seeking to answer questions that remain about the pathogen and disease cycle.
Host: BLS is vectored mainly by insects in the leafhopper (Cicadellidae) and the spittlebug (Cercopidae) families, but research is being conducted to evaluate additional vectors.
Symptoms: BLS symptoms are very irregular. Leaves emerge healthy in the spring, but with the onset of hot, dry weather, symptoms of noticeable premature leaf browning develop rapidly during July and August. Trees with chronic disease may leaf out late and have light green leaves. The general symptoms of most trees include a characteristic leaf scorch that progresses inward from the browning of the margins and results in premature defoliation across all tree species. In the earliest stages, there may only be a few limbs that display foliar symptoms within the crown, but as a result of scorching and premature defoliation over the years, limb dieback and water sprouts develop. Because the trees are stressed from this disease, during the course of several years, they become more susceptible to secondary pests such as cankers and borers. Life expectancy is 5 to 10 years.
Diagnosis: This can be difficult in the field due to the indistinct symptoms produced by the disease. The symptoms are indicative of many other problems that inhibit water movement in the xylem. Because of this, close attention must be paid to the host species involved and adequate and proper testing.
Treatment of the Disease: Some products have delayed the onset of symptoms and extend the life of some species of trees. However, if the treatments are not performed annually, symptoms return. There is no effective long-term cure.
Commonly Infected Species
Pin Oak (Quercus palustris)*
Southern Red Oak (Quercus falcata)*
Northern Red Oak (Quercus rubra)*
Sycamore (Platanus occidentalis)
Native Elm (Ulmus americana)
London Plane Tree (Platanus x acerifolia)
Mulberry (Morus alba)
Almond (Prunus glanduiosa)
Oleander (Nerium oleander)
Scarlet Oak (Quercus coccinea)
Shingle Oak (Quercus imbricaria)
White Oak (Quercus alba)
Hackberry (Celtis occidentalis)
*primary victims
Susceptible, but Infrequently Infected Species
Red Maple (Acer rubrum)
Sweetgum (Liquidambar stryaciflua)
Sugar Maple (Acer saccharum)
Boxelder (Acer negundo)
Bur Oak (Quercus macrocarpa)
Dogwood (Cornus florida)
Willow Oak (Quercus phellos)
Water Oak (Quercus nigra)
Live Oak (Quercus virginiana)
Photo
Sources
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the .5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to gibneyCE.com’. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
This disease is actually spread by insects and unfortunately no good cure is available.
Common Name: Bacterial Leaf Scorch (BLS)
Pathogen: BLS is spread by a xylem-limited bacterium Xylella fastidiosa.
Common Causes: This bacterium causes decline and death of many herbaceous and woody plant hosts due to restriction of water flow from the roots to the crown of the plant.
Location: BLS is established in almost all warm areas of the US as far north as New Jersey, through the south, west to Texas, and in California. There has also been confirmation of the disease occurring in Illinois.
Introduction: This pathogen was first discovered in grapes and causes Pierce's Disease. BLS is a newly recognized disease and many researchers are currently seeking to answer questions that remain about the pathogen and disease cycle.
Host: BLS is vectored mainly by insects in the leafhopper (Cicadellidae) and the spittlebug (Cercopidae) families, but research is being conducted to evaluate additional vectors.
Symptoms: BLS symptoms are very irregular. Leaves emerge healthy in the spring, but with the onset of hot, dry weather, symptoms of noticeable premature leaf browning develop rapidly during July and August. Trees with chronic disease may leaf out late and have light green leaves. The general symptoms of most trees include a characteristic leaf scorch that progresses inward from the browning of the margins and results in premature defoliation across all tree species. In the earliest stages, there may only be a few limbs that display foliar symptoms within the crown, but as a result of scorching and premature defoliation over the years, limb dieback and water sprouts develop. Because the trees are stressed from this disease, during the course of several years, they become more susceptible to secondary pests such as cankers and borers. Life expectancy is 5 to 10 years.
Diagnosis: This can be difficult in the field due to the indistinct symptoms produced by the disease. The symptoms are indicative of many other problems that inhibit water movement in the xylem. Because of this, close attention must be paid to the host species involved and adequate and proper testing.
Treatment of the Disease: Some products have delayed the onset of symptoms and extend the life of some species of trees. However, if the treatments are not performed annually, symptoms return. There is no effective long-term cure.
- Maintaining the health of the tree through proper mulching and irrigation practices may delay and suppress the symptoms of the disease by assuring adequate moisture availability for the tree.
- Fertilization should be based on soil analysis results.
- Secondary pests, including canker diseases, borers and bark beetles, should be monitored and controlled as needed.
- There is no data to suggest that sanitation reduces the incidence of new infections. Pruning out diseased limbs as a means of eradicating the disease also has not been shown effective.
Commonly Infected Species
Pin Oak (Quercus palustris)*
Southern Red Oak (Quercus falcata)*
Northern Red Oak (Quercus rubra)*
Sycamore (Platanus occidentalis)
Native Elm (Ulmus americana)
London Plane Tree (Platanus x acerifolia)
Mulberry (Morus alba)
Almond (Prunus glanduiosa)
Oleander (Nerium oleander)
Scarlet Oak (Quercus coccinea)
Shingle Oak (Quercus imbricaria)
White Oak (Quercus alba)
Hackberry (Celtis occidentalis)
*primary victims
Susceptible, but Infrequently Infected Species
Red Maple (Acer rubrum)
Sweetgum (Liquidambar stryaciflua)
Sugar Maple (Acer saccharum)
Boxelder (Acer negundo)
Bur Oak (Quercus macrocarpa)
Dogwood (Cornus florida)
Willow Oak (Quercus phellos)
Water Oak (Quercus nigra)
Live Oak (Quercus virginiana)
Photo
Sources
- Bartlett Tree Research Laboratories, “Bacterial Leaf Scorch, Identification and Management” Technical Report. No date.
- Hartman, John, “Bacterial Leaf Scorch is Visible Now”, Kentucky Press News, August 2, 2006.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the .5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to gibneyCE.com’. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Cultivars of Snowbell
Edited by Len Phillips
Snowbells are handsome small trees that do well in almost every landscape situation. The attractive flowers draw people to the tree to see them up close. 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 information below is common to all the cultivars of snowbell.
Trade Name: Japanese Snowbell
Botanical Name: Styrax japonicus
Family: Styraceae
Hardiness Zone: 5 – 8
Growth Rate: Medium, 9' to 10' in 10 years
Bloom Period: July
Fruit: A dry grayish pod
Bark: Smooth with orange-brown fissures
Habitat: Grows well everywhere
Culture: Prefers moist, acidic, well-drained soil with plenty of organic matter
Pest Problems: None
Storm Resistance: Good
Salt Tolerance: Good
Planting: B&B, bare root, or container grown, suitable for planting in CU-Structural Soil
Pruning: Low branches may need raising
Propagating: Softwood cuttings
Design Uses: Specimen for lawn, park, and residential locations
Evening Light Snowbell Styrax japonicus ‘Evening Light’ Plant Patent #24168 – Height: 15'; Spread: 10'; Shape: upright oval; Foliage: dark purple; Flower: white and bell-shaped.
Glossy deep purple foliage is unique among snowbells, providing a dramatically dark backdrop for fragrant white, bell shaped flowers that appear in June. With adequate soil moisture, some reblooming will occur.
Photo
Fragrant Fountain Snowbell Styrax japonicus ‘Fragrant Fountain’ Plant Patent #19664 – Height: 8'; Spread: 6'; Shape: weeping; Foliage: dark green and fine textured leaves; Fall Color: yellowish; Flower: pure white and bell-shaped.
A cascade of fragrant blooms and dark green, glossy leaves smother the delicately weeping branches of this small garden-sized tree. It blooms heavily at a young age, and appears more tolerant of temperature extremes than most seedlings of the species. The leader is easily trained to reach a desired height, from which it weeps gracefully. Photo
Pink Chimes Snowbell Styrax japonicus ‘Pink Chimes’ – Height: 15'; Spread: 15'; Shape: rounded with spreading branches; Foliage: dark green; Fall Color: yellowish; Flower: pink and bell-shaped.
Delicate pink flowers cover this tree as summer begins. Smaller and slower growing than the white cultivars, it has a delicate branch structure that is upright at first, and then spreads horizontally with some branches almost weeping. Outstanding in full bloom. Photo
Snow Charm® Japanese Snowbell Styrax japonicus ‘JFS-E’ – Height: 20'; Spread: 20'; Shape: rounded; Foliage: dark green; Fall Color: yellowish; Flower: pure white bell shaped flowers.
Reliable and easy to grow, this tree was selected from a highly variable species and this selection assures a rounded form. It resists twig dieback but has larger leaves and a broader, more traditional form. Photo
Snowcone® Japanese Snowbell Styrax japonicus ‘JFS-D’ – Height: 25’; Spread: 20’; Shape: broadly pyramidal and dense; Foliage: dark green and fine textured; Fall Color: yellowish; Flower: pure white and bell shaped.
The dark green foliage, combining with symmetrical, upright branches creates a slender uniform appearing tree. It is resistant to twig dieback that is common in seedling grown trees. Photo
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the .5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to gibneyCE.com’. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
Snowbells are handsome small trees that do well in almost every landscape situation. The attractive flowers draw people to the tree to see them up close. 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 information below is common to all the cultivars of snowbell.
Trade Name: Japanese Snowbell
Botanical Name: Styrax japonicus
Family: Styraceae
Hardiness Zone: 5 – 8
Growth Rate: Medium, 9' to 10' in 10 years
Bloom Period: July
Fruit: A dry grayish pod
Bark: Smooth with orange-brown fissures
Habitat: Grows well everywhere
Culture: Prefers moist, acidic, well-drained soil with plenty of organic matter
Pest Problems: None
Storm Resistance: Good
Salt Tolerance: Good
Planting: B&B, bare root, or container grown, suitable for planting in CU-Structural Soil
Pruning: Low branches may need raising
Propagating: Softwood cuttings
Design Uses: Specimen for lawn, park, and residential locations
Evening Light Snowbell Styrax japonicus ‘Evening Light’ Plant Patent #24168 – Height: 15'; Spread: 10'; Shape: upright oval; Foliage: dark purple; Flower: white and bell-shaped.
Glossy deep purple foliage is unique among snowbells, providing a dramatically dark backdrop for fragrant white, bell shaped flowers that appear in June. With adequate soil moisture, some reblooming will occur.
Photo
Fragrant Fountain Snowbell Styrax japonicus ‘Fragrant Fountain’ Plant Patent #19664 – Height: 8'; Spread: 6'; Shape: weeping; Foliage: dark green and fine textured leaves; Fall Color: yellowish; Flower: pure white and bell-shaped.
A cascade of fragrant blooms and dark green, glossy leaves smother the delicately weeping branches of this small garden-sized tree. It blooms heavily at a young age, and appears more tolerant of temperature extremes than most seedlings of the species. The leader is easily trained to reach a desired height, from which it weeps gracefully. Photo
Pink Chimes Snowbell Styrax japonicus ‘Pink Chimes’ – Height: 15'; Spread: 15'; Shape: rounded with spreading branches; Foliage: dark green; Fall Color: yellowish; Flower: pink and bell-shaped.
Delicate pink flowers cover this tree as summer begins. Smaller and slower growing than the white cultivars, it has a delicate branch structure that is upright at first, and then spreads horizontally with some branches almost weeping. Outstanding in full bloom. Photo
Snow Charm® Japanese Snowbell Styrax japonicus ‘JFS-E’ – Height: 20'; Spread: 20'; Shape: rounded; Foliage: dark green; Fall Color: yellowish; Flower: pure white bell shaped flowers.
Reliable and easy to grow, this tree was selected from a highly variable species and this selection assures a rounded form. It resists twig dieback but has larger leaves and a broader, more traditional form. Photo
Snowcone® Japanese Snowbell Styrax japonicus ‘JFS-D’ – Height: 25’; Spread: 20’; Shape: broadly pyramidal and dense; Foliage: dark green and fine textured; Fall Color: yellowish; Flower: pure white and bell shaped.
The dark green foliage, combining with symmetrical, upright branches creates a slender uniform appearing tree. It is resistant to twig dieback that is common in seedling grown trees. Photo
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the .5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to gibneyCE.com’. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Dealing with Soot Pollution
Edited By Len Phillips
Trees do more than just provide oxygen and shade. A recent study suggests they can make cities healthier. Researchers with the USDA Forest Service and the Davey Institute determined that foliage in urban areas can scrub enough soot out of the air to reduce asthma attacks, emergency room visits, heart attacks, lung cancer, and premature deaths. Soot is a mass of impure carbon particles resulting from the incomplete combustion of hydrocarbons. Soot is theorized to be the second-largest cause of global warming.
Urban air contains fine particles from diesel engine emissions, car and truck exhaust, power plant emissions, wood fuel smoke, biochar and charcoal generation facilities, and other various industrial pollutants. The smallest particles, those measuring less than one-seventh the width of a human hair, can become lodged deep in the lungs where they can aggravate respiratory or cardiovascular conditions and lead to premature death. Children are at the greatest health risk from air pollution because they are more likely to be active outdoors and their lungs are still developing.
Laboratory studies have shown that tree leaves can act as filters, collecting the fine particles in the air. These particles will remain on the leaves until rainfall washes the buildup off the leaves and onto the ground or stiff winds knock the particles off the leaves and back into the air.
Scientists have long known that trees reduce smog and ozone pollution. This recent study focused on the fine air-borne particles or soot and estimated the respiratory benefits that trees provide to calm breathing problems and estimated the lives saved. For cities like Atlanta with an abundant tree canopy, the pollution-removing effect of leaves is significant. However, in the more populous New York City, the impact on people's health is more pronounced. The study estimated that up to eight deaths were avoided because of the trees in New York.
In Baltimore MD, trees remove roughly 14 tons of pollution annually. As a result, there was one less premature death, nearly 140 fewer asthma attacks, and 240 cases of labored breathing avoided in Baltimore each year. The health benefits of trees are about average in Baltimore, but it is not necessarily going to stay that way. Baltimore has been losing trees and canopy over the past decade to the point where trees now cover just 27% of the landscape. Of those trees, 16% to 20% of what is left is considered distressed, diseased, or dying.
The city has vowed to increase tree cover to 40% of the landscape by 2040 but the city's tree-planting efforts are less than half what would be needed to reach that goal, according to the Baltimore Tree Trust, a nonprofit dedicated to re-leafing the city. Groups like the Trust are trying to supplement the work of the cash-strapped municipal government. The group is focusing their planting efforts on urban neighborhoods which have the highest asthma rates and the fewest trees. At its first project volunteers have put in 154 big trees in the past year with hopes to add 650 more in the next few years. This should be enough to boost tree cover there from 13% to the citywide goal of 40%.
But trees are not a cheap fix for air pollution. A dense canopy of trees may trap emissions preventing them from being dispersed by winds. However, pollution can also damage these trees, reducing their environmental benefits. Ozone, a highly reactive gas in smog, can burn foliage, while fine particles can lodge themselves in the stomata of the leaves, preventing them from taking in carbon dioxide and giving off oxygen and water vapor.
Unfortunately, there is another recent study that suggests that trees exposed to air pollution can actually make the pollution worse under certain circumstances. Isoprene, an organic compound given off by certain trees to protect their leaves, reacts with nitrogen oxides from vehicle exhaust, power plants, and other sources, to produce fine particle-sized toxic pollutants.
Sources
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the .5 CEUs toward Certified Arborist, Municipal Specialist, 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.
Edited By Len Phillips
Trees do more than just provide oxygen and shade. A recent study suggests they can make cities healthier. Researchers with the USDA Forest Service and the Davey Institute determined that foliage in urban areas can scrub enough soot out of the air to reduce asthma attacks, emergency room visits, heart attacks, lung cancer, and premature deaths. Soot is a mass of impure carbon particles resulting from the incomplete combustion of hydrocarbons. Soot is theorized to be the second-largest cause of global warming.
Urban air contains fine particles from diesel engine emissions, car and truck exhaust, power plant emissions, wood fuel smoke, biochar and charcoal generation facilities, and other various industrial pollutants. The smallest particles, those measuring less than one-seventh the width of a human hair, can become lodged deep in the lungs where they can aggravate respiratory or cardiovascular conditions and lead to premature death. Children are at the greatest health risk from air pollution because they are more likely to be active outdoors and their lungs are still developing.
Laboratory studies have shown that tree leaves can act as filters, collecting the fine particles in the air. These particles will remain on the leaves until rainfall washes the buildup off the leaves and onto the ground or stiff winds knock the particles off the leaves and back into the air.
Scientists have long known that trees reduce smog and ozone pollution. This recent study focused on the fine air-borne particles or soot and estimated the respiratory benefits that trees provide to calm breathing problems and estimated the lives saved. For cities like Atlanta with an abundant tree canopy, the pollution-removing effect of leaves is significant. However, in the more populous New York City, the impact on people's health is more pronounced. The study estimated that up to eight deaths were avoided because of the trees in New York.
In Baltimore MD, trees remove roughly 14 tons of pollution annually. As a result, there was one less premature death, nearly 140 fewer asthma attacks, and 240 cases of labored breathing avoided in Baltimore each year. The health benefits of trees are about average in Baltimore, but it is not necessarily going to stay that way. Baltimore has been losing trees and canopy over the past decade to the point where trees now cover just 27% of the landscape. Of those trees, 16% to 20% of what is left is considered distressed, diseased, or dying.
The city has vowed to increase tree cover to 40% of the landscape by 2040 but the city's tree-planting efforts are less than half what would be needed to reach that goal, according to the Baltimore Tree Trust, a nonprofit dedicated to re-leafing the city. Groups like the Trust are trying to supplement the work of the cash-strapped municipal government. The group is focusing their planting efforts on urban neighborhoods which have the highest asthma rates and the fewest trees. At its first project volunteers have put in 154 big trees in the past year with hopes to add 650 more in the next few years. This should be enough to boost tree cover there from 13% to the citywide goal of 40%.
But trees are not a cheap fix for air pollution. A dense canopy of trees may trap emissions preventing them from being dispersed by winds. However, pollution can also damage these trees, reducing their environmental benefits. Ozone, a highly reactive gas in smog, can burn foliage, while fine particles can lodge themselves in the stomata of the leaves, preventing them from taking in carbon dioxide and giving off oxygen and water vapor.
Unfortunately, there is another recent study that suggests that trees exposed to air pollution can actually make the pollution worse under certain circumstances. Isoprene, an organic compound given off by certain trees to protect their leaves, reacts with nitrogen oxides from vehicle exhaust, power plants, and other sources, to produce fine particle-sized toxic pollutants.
Sources
- Wheeler, Timothy B., “Trees can help with soot pollution”, The Baltimore Sun, July 14, 2013.
- Eilperin, Juliet, “Black carbon ranks as second-biggest human cause of global warming”, The Washington Post, November 26, 2013.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 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.