Seminar #73 from Online Seminars for Municipal Arborists – March / April 2017
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.
Living Mulch
By Len Phillips
In the practice of general plant care, a living mulch is a ground cover plant growing at the base of a tree. Living mulches are sometimes used at locations where the tree is growing in a sidewalk tree cut-out and the living mulch (plants) are growing around the tree. The living mulch is intended to beautify and replace the need for a tree grate or conventional mulch by using plants to provide weed suppression, control of the soil temperature, and a visual means to discourage people from walking close to the tree and causing soil compaction. Living mulches can reduce water runoff and erosion, and filter surface water runoff for use by the tree. Living mulches have also been shown to increase the population of organisms which enhance the quality of the soil. Living mulches are intended to grow for many years in harmony with the tree. Opponents of this concept believe the living mulch robs the tree of soil moisture, nutrients, and microorganisms. But the fact is that these plants actually help the tree by preventing evaporation of soil moisture and converting nutrients into forms that are useful for the tree.
Plant selection for creating a living mulch is not an easy task. While just about any plant might grow in harmony with a tree in a conventional landscape, very few will thrive living in the sidewalk cutout surrounded by concrete. The planting of the ground covers may occur anytime including right after the tree has been planted. The plants should be planted on a grade of no more than 1 inch (2.5 cm) below the sidewalk elevation to hold runoff water for the plants and tree. The living mulch plants should be carefully placed around the outside edge of the sidewalk cutout to avoid any conflict with the newly developing tree roots and the underground root stabilizing system.
Never plant anything within 12" (30 cm) of the flare. No part of the tree's trunk and bark should ever be covered with anything that retains moisture. Doing so encourages rot. In addition, any planting of small ground covers needs to be done carefully so as not to damage the existing tree's roots. Open areas should still be mulched with composted wood chips so the soil is never left bare.
Most Desirable Living Mulches
The following, in this author's opinion, are the best living mulches because they are vigorous ground covers and will tolerate pedestrian traffic, winter snow plow damage, and erratic weather conditions:
White clover Trifolium repens - Clovers with their deep roots, provide resistance to soil compaction. Legume living mulches also have some important positive effects on the nutrient cycling that benefit the tree. For example, clover fixes the atmospheric nitrogen that is important for tree growth and it is effective for enhancing and recycling the soil's nutrients. Clover has the ability to grow in sun or shade, maintain a low profile, thrive if repeatedly mowed and it will withstand foot traffic. It is considered by many as the best choice for a living mulch. In established stands, it also may provide some nitrogen suitable for use by the tree.
Vinca Vinca minor - Vinca does well in all light conditions and, once established, is fairly tolerant of a less than desirable site and soil conditions. Vinca is a shallow rooted creeper that tolerates soil compaction and pedestrian foot traffic, once it is established. It should be planted with quart size plants that have large root systems to reduce the time for the plant to become established. These larger plants are quite developed and fewer plants are needed so there's a lot less disturbance in the sidewalk cutout area. Impact on the tree is minimal.
Creepers
Creepers are plants that can grow to cover the soil from the outside edge of the sidewalk cutout where there is more light, and they may grow toward the trunk of the tree with time. These are all shallow-rooted perennials with roots in the top 6 inches (15 cm) of soil, and therefore, above the tree's main roots. They are all tolerant of varying sun exposures. Creepers do require weeding and extra water for the first few years but once established, the plants look outstanding all year. All the plants cool the roots and discourage any compacting foot traffic. Reports indicate that there has to be some assumed nutrient competition between tree and the ground cover but these reports also indicate that both the tree and the creepers appear to be living in harmony. Some of the best creepers for this function include:
Ajuga Ajuga reptans
Peanut Arachis repens
Epimedium Epimedium spp.
Wild Woodland Strawberry Fragaria vesca
Coral Bells Heuchera spp.
Mini and dwarf Hosta vareities Hosta spp.
Yellowroot (Golden Seal) Hydrastis Canadensis
Liriope Liriope muscari
Cupflower Mazus reptans
Pachysandra Pachysandra
Ginseng Panax quinquefolius
Woodland Phlox Phlox divaricate
Stonecrop Sedum spp.
Comfrey Symphytum officinale
Creeping Thyme Thymus serpyllum
Turkish Speedwell Veronica liwanensis
Barren Strawberry Waldsteinia ternate
Hardy Ferns Several species are suitable for living mulch, especially in somewhat shady areas.
Undesirable Living Mulches
Not only are the plants listed below considered invasive in many locations, they can also cause moisture retention, root rot, and other problems for the tree. Many of these plants can also climb over the entire tree. NOT recommended are:
Porcelain Berry Ampelopsis brevipedunculata
Climbing Euonymus Euonymus fortunei
English Ivy Hedera helix
Kudzu Pueraria lobata
Bittersweet Solanum dulcamara
Poison Ivy Toxicodendron radicans
Grape Vitis spp.
Wisteria Wisteria spp.
Annuals – Growing annuals under young trees is the exception to being good for trees. Annuals are
aggressive growers and they can cause growth reduction to the tree because of the competition for soil
nutrients. Annuals also need lots of water and weekly maintenance.
Shrubs – Often young trees have been planted and combined with nice flowering shrubs. Over time the trees
will win the competition and the shrubs look terrible and need to be removed, so they are not a good choice in
the sidewalk cut out areas.
Creeping Juniper Juniperus horizontalis is a very popular group of junipers that require a lot of maintenance
to keep them from growing over the flare and sidewalk, while also encouraging pest and disease problems
causing harm to the tree. These problems are in addition to the problems mentioned above with annuals and
shrubs.
Caution
Not all trees are created equal. Each requires specific light, soil, and moisture conditions to survive and remain healthy. Some tree species are extremely sensitive to major soil disturbance. Planting beneath trees that are sensitive to having their roots disturbed may need to have the proposed plantings scaled back or carried out over a few years.
Source
Special thanks to members of LinkedIn's Urban Forestry discussion group for sharing their favorite living mulches.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Living Mulch
By Len Phillips
In the practice of general plant care, a living mulch is a ground cover plant growing at the base of a tree. Living mulches are sometimes used at locations where the tree is growing in a sidewalk tree cut-out and the living mulch (plants) are growing around the tree. The living mulch is intended to beautify and replace the need for a tree grate or conventional mulch by using plants to provide weed suppression, control of the soil temperature, and a visual means to discourage people from walking close to the tree and causing soil compaction. Living mulches can reduce water runoff and erosion, and filter surface water runoff for use by the tree. Living mulches have also been shown to increase the population of organisms which enhance the quality of the soil. Living mulches are intended to grow for many years in harmony with the tree. Opponents of this concept believe the living mulch robs the tree of soil moisture, nutrients, and microorganisms. But the fact is that these plants actually help the tree by preventing evaporation of soil moisture and converting nutrients into forms that are useful for the tree.
Plant selection for creating a living mulch is not an easy task. While just about any plant might grow in harmony with a tree in a conventional landscape, very few will thrive living in the sidewalk cutout surrounded by concrete. The planting of the ground covers may occur anytime including right after the tree has been planted. The plants should be planted on a grade of no more than 1 inch (2.5 cm) below the sidewalk elevation to hold runoff water for the plants and tree. The living mulch plants should be carefully placed around the outside edge of the sidewalk cutout to avoid any conflict with the newly developing tree roots and the underground root stabilizing system.
Never plant anything within 12" (30 cm) of the flare. No part of the tree's trunk and bark should ever be covered with anything that retains moisture. Doing so encourages rot. In addition, any planting of small ground covers needs to be done carefully so as not to damage the existing tree's roots. Open areas should still be mulched with composted wood chips so the soil is never left bare.
Most Desirable Living Mulches
The following, in this author's opinion, are the best living mulches because they are vigorous ground covers and will tolerate pedestrian traffic, winter snow plow damage, and erratic weather conditions:
White clover Trifolium repens - Clovers with their deep roots, provide resistance to soil compaction. Legume living mulches also have some important positive effects on the nutrient cycling that benefit the tree. For example, clover fixes the atmospheric nitrogen that is important for tree growth and it is effective for enhancing and recycling the soil's nutrients. Clover has the ability to grow in sun or shade, maintain a low profile, thrive if repeatedly mowed and it will withstand foot traffic. It is considered by many as the best choice for a living mulch. In established stands, it also may provide some nitrogen suitable for use by the tree.
Vinca Vinca minor - Vinca does well in all light conditions and, once established, is fairly tolerant of a less than desirable site and soil conditions. Vinca is a shallow rooted creeper that tolerates soil compaction and pedestrian foot traffic, once it is established. It should be planted with quart size plants that have large root systems to reduce the time for the plant to become established. These larger plants are quite developed and fewer plants are needed so there's a lot less disturbance in the sidewalk cutout area. Impact on the tree is minimal.
Creepers
Creepers are plants that can grow to cover the soil from the outside edge of the sidewalk cutout where there is more light, and they may grow toward the trunk of the tree with time. These are all shallow-rooted perennials with roots in the top 6 inches (15 cm) of soil, and therefore, above the tree's main roots. They are all tolerant of varying sun exposures. Creepers do require weeding and extra water for the first few years but once established, the plants look outstanding all year. All the plants cool the roots and discourage any compacting foot traffic. Reports indicate that there has to be some assumed nutrient competition between tree and the ground cover but these reports also indicate that both the tree and the creepers appear to be living in harmony. Some of the best creepers for this function include:
Ajuga Ajuga reptans
Peanut Arachis repens
Epimedium Epimedium spp.
Wild Woodland Strawberry Fragaria vesca
Coral Bells Heuchera spp.
Mini and dwarf Hosta vareities Hosta spp.
Yellowroot (Golden Seal) Hydrastis Canadensis
Liriope Liriope muscari
Cupflower Mazus reptans
Pachysandra Pachysandra
Ginseng Panax quinquefolius
Woodland Phlox Phlox divaricate
Stonecrop Sedum spp.
Comfrey Symphytum officinale
Creeping Thyme Thymus serpyllum
Turkish Speedwell Veronica liwanensis
Barren Strawberry Waldsteinia ternate
Hardy Ferns Several species are suitable for living mulch, especially in somewhat shady areas.
Undesirable Living Mulches
Not only are the plants listed below considered invasive in many locations, they can also cause moisture retention, root rot, and other problems for the tree. Many of these plants can also climb over the entire tree. NOT recommended are:
Porcelain Berry Ampelopsis brevipedunculata
Climbing Euonymus Euonymus fortunei
English Ivy Hedera helix
Kudzu Pueraria lobata
Bittersweet Solanum dulcamara
Poison Ivy Toxicodendron radicans
Grape Vitis spp.
Wisteria Wisteria spp.
Annuals – Growing annuals under young trees is the exception to being good for trees. Annuals are
aggressive growers and they can cause growth reduction to the tree because of the competition for soil
nutrients. Annuals also need lots of water and weekly maintenance.
Shrubs – Often young trees have been planted and combined with nice flowering shrubs. Over time the trees
will win the competition and the shrubs look terrible and need to be removed, so they are not a good choice in
the sidewalk cut out areas.
Creeping Juniper Juniperus horizontalis is a very popular group of junipers that require a lot of maintenance
to keep them from growing over the flare and sidewalk, while also encouraging pest and disease problems
causing harm to the tree. These problems are in addition to the problems mentioned above with annuals and
shrubs.
Caution
Not all trees are created equal. Each requires specific light, soil, and moisture conditions to survive and remain healthy. Some tree species are extremely sensitive to major soil disturbance. Planting beneath trees that are sensitive to having their roots disturbed may need to have the proposed plantings scaled back or carried out over a few years.
Source
Special thanks to members of LinkedIn's Urban Forestry discussion group for sharing their favorite living mulches.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Tree Risk Management
By Gordon Mann
The purpose of assessing a tree for risk is to reduce the likelihood of failure of a tree part or the whole tree without removing every tree that may have some noticeable defect or problem. Tree risk management includes many facets such as:
· understanding a site's use,
· potential tree conditions prone to or subject to failure within a certain time frame,
· locating potential targets,
· studying the likelihood of the whole tree or tree part striking a target,
· determining the severity of a failed tree part or whole tree striking a target,
· looking at the conflicts present on the site associated with the tree,
· and can these conditions or situations be mitigated.
While some trees may only be mitigated by removal, most trees I look at can have the risk reduced by other maintenance practices such as pruning or target removal.
A Target
A target is any object or person that may be struck if a part or the whole tree fails. The typical target zone is the ground area around a tree where a tree or tree part may land if a failure occurs. On level ground, the target zone may be the radius of the height of the tree, or the area where an identified branch may land. On slopes or under certain site conditions, the target zone may be one and one-half times the height of the tree or length of the branch.
The Site
The site, or use of a site indicates the targets. Sites may be the easiest part of risk reduction or sites may be very difficult. If a movable target is under a high risk tree and the target can be moved outside of the tree failure target zone, the risk is reduced or eliminated. An example of moving targets might be apparent during catastrophic wildfires or significant storm incidents when people are evacuated to reduce the risk of injury or death. A site can simply be closed and eliminate all site use to avoid risk. When an immovable object like a garage is within the tree failure target zone of a high risk tree, maybe the garage contents can be moved to a different location. If the site cannot be controlled to limit the likelihood of a failure striking a target, the need may involve removing a faulty tree part or entire tree to protect the targets on a site.
Conflicts
Conflicts are those situations affected by the tree or parts of the tree that impact other human activities, and create a risk but not related to the tree or branch failing. Examples include roots raising sidewalks or curbs, roots in sewer lines, roots displacing irrigation lines, tree branches contacting a home or roof, tree branches obstructing views or visibility such as a stop sign or traffic signal, and tree branches touching power lines.
Other conflicts such as pollen, or fruit on a sidewalk, and pests of trees causing dripping and sticky messes that are inconveniences and nuisances to human lives, may create risk. One conflict necessary to consider is obstruction to a road or walkway. Many people have become so focused on their cell phones that they do not look where they are going, and while peering at their phone screen may walk into a low tree part and become injured.
Time Frame for the Risk Assessment
It is very important to determine the time frame the risk assessment will cover. For example, if the time frame is 100 years, most trees we look at will fail, the risk ratings will be higher for each tree, and the mitigation options will be very long and descriptive. If we are looking at the likelihood of failure under normal conditions for 3 years, it will be very different. The observations and likelihood of failure are going to be more manageable in a 3-year assessment and the mitigation options will be based on something that will have an immediate affect to address current risk. When the risk assessment assignment is established, the time frame must be clear and used as the basis for observations and identifying mitigation options to reduce risk.
A different time frame to consider is the time between risk assessments. This determination is usually made after the first assessment and is based on the age and size of the tree population, condition, species, maintenance practices, site use, and the risk observed during the first assessment.
Mitigation
If the defect, risk element associated with the tree can be cleared, corrected, or eliminated, or targets can be removed, the risk-reducing action is considered mitigation. Mitigation is the action used to reduce risk from failures and conflicts, and can include:
· spraying a pest
· pruning
· cabling and bracing
· tree removal
· target relocation
· site management
Actions that may not touch the tree might include moving the target or the competing infrastructure, or restricting the site use. Some mitigation combines restricting use or moving competing infrastructure or target with tree work.
Risk Management
The risk management approach is a systematic process to identify and mitigate risk. Risk can be identified in different levels and priorities. People and agencies have different tolerances for risk. The risk management approach requires an understanding of the risk present; the consequences if the identified condition occurs; options to reduce or avoid the event from happening; and the tolerances of the tree owner.
Risk management is a practice to understand the risk present, and use the available resources to reduce the risk to a tolerable level. With trees, we can rarely eliminate all risk without eliminating all trees.
Gordon Mann is an ASCA Registered Consulting Arborist, an ISA Certified Arborist and Municipal Specialist, TRAQ Qualified Tree Risk Assessor, and urban forestry consultant in Auburn, CA. He is the SMA ANSI A300 Committee alternate and a Director on the ISA Board.
Editor's Note: In the next Seminar, Gordon will take risk management to the next level with the creation of a Tree Risk Management Plan.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Gordon Mann
The purpose of assessing a tree for risk is to reduce the likelihood of failure of a tree part or the whole tree without removing every tree that may have some noticeable defect or problem. Tree risk management includes many facets such as:
· understanding a site's use,
· potential tree conditions prone to or subject to failure within a certain time frame,
· locating potential targets,
· studying the likelihood of the whole tree or tree part striking a target,
· determining the severity of a failed tree part or whole tree striking a target,
· looking at the conflicts present on the site associated with the tree,
· and can these conditions or situations be mitigated.
While some trees may only be mitigated by removal, most trees I look at can have the risk reduced by other maintenance practices such as pruning or target removal.
A Target
A target is any object or person that may be struck if a part or the whole tree fails. The typical target zone is the ground area around a tree where a tree or tree part may land if a failure occurs. On level ground, the target zone may be the radius of the height of the tree, or the area where an identified branch may land. On slopes or under certain site conditions, the target zone may be one and one-half times the height of the tree or length of the branch.
The Site
The site, or use of a site indicates the targets. Sites may be the easiest part of risk reduction or sites may be very difficult. If a movable target is under a high risk tree and the target can be moved outside of the tree failure target zone, the risk is reduced or eliminated. An example of moving targets might be apparent during catastrophic wildfires or significant storm incidents when people are evacuated to reduce the risk of injury or death. A site can simply be closed and eliminate all site use to avoid risk. When an immovable object like a garage is within the tree failure target zone of a high risk tree, maybe the garage contents can be moved to a different location. If the site cannot be controlled to limit the likelihood of a failure striking a target, the need may involve removing a faulty tree part or entire tree to protect the targets on a site.
Conflicts
Conflicts are those situations affected by the tree or parts of the tree that impact other human activities, and create a risk but not related to the tree or branch failing. Examples include roots raising sidewalks or curbs, roots in sewer lines, roots displacing irrigation lines, tree branches contacting a home or roof, tree branches obstructing views or visibility such as a stop sign or traffic signal, and tree branches touching power lines.
Other conflicts such as pollen, or fruit on a sidewalk, and pests of trees causing dripping and sticky messes that are inconveniences and nuisances to human lives, may create risk. One conflict necessary to consider is obstruction to a road or walkway. Many people have become so focused on their cell phones that they do not look where they are going, and while peering at their phone screen may walk into a low tree part and become injured.
Time Frame for the Risk Assessment
It is very important to determine the time frame the risk assessment will cover. For example, if the time frame is 100 years, most trees we look at will fail, the risk ratings will be higher for each tree, and the mitigation options will be very long and descriptive. If we are looking at the likelihood of failure under normal conditions for 3 years, it will be very different. The observations and likelihood of failure are going to be more manageable in a 3-year assessment and the mitigation options will be based on something that will have an immediate affect to address current risk. When the risk assessment assignment is established, the time frame must be clear and used as the basis for observations and identifying mitigation options to reduce risk.
A different time frame to consider is the time between risk assessments. This determination is usually made after the first assessment and is based on the age and size of the tree population, condition, species, maintenance practices, site use, and the risk observed during the first assessment.
Mitigation
If the defect, risk element associated with the tree can be cleared, corrected, or eliminated, or targets can be removed, the risk-reducing action is considered mitigation. Mitigation is the action used to reduce risk from failures and conflicts, and can include:
· spraying a pest
· pruning
· cabling and bracing
· tree removal
· target relocation
· site management
Actions that may not touch the tree might include moving the target or the competing infrastructure, or restricting the site use. Some mitigation combines restricting use or moving competing infrastructure or target with tree work.
Risk Management
The risk management approach is a systematic process to identify and mitigate risk. Risk can be identified in different levels and priorities. People and agencies have different tolerances for risk. The risk management approach requires an understanding of the risk present; the consequences if the identified condition occurs; options to reduce or avoid the event from happening; and the tolerances of the tree owner.
Risk management is a practice to understand the risk present, and use the available resources to reduce the risk to a tolerable level. With trees, we can rarely eliminate all risk without eliminating all trees.
Gordon Mann is an ASCA Registered Consulting Arborist, an ISA Certified Arborist and Municipal Specialist, TRAQ Qualified Tree Risk Assessor, and urban forestry consultant in Auburn, CA. He is the SMA ANSI A300 Committee alternate and a Director on the ISA Board.
Editor's Note: In the next Seminar, Gordon will take risk management to the next level with the creation of a Tree Risk Management Plan.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Tree of the Seminar #73
By Len Phillips
Autumn Treasure Hophornbeam is a cultivar from a native hophornbeam also known as Ironwood and it is an ideal tree for naturalistic landscaping. Autumn Treasure Hophornbeam is suited for city living and has an upright narrow form that facilitates uniform street tree plantings.
Trade Name: Autumn Treasure® Hophornbeam
Botanical Name: Ostyra virginiana ‘JFS-KW5’
Family: Betulaceae
Parentage: Native species
Height: 30' - 40'
Spread: 20' - 25'
Form: Upright, narrow form
Flower: Small catkins, 1” long
Fruit: Nutlet is 1/2” long, resembles hops
Foliage: Serrated leaves
Spring Color: Pale yellowish-green flowers, stems and young leaves
Summer Foliage: Dark green
Autumn Foliage: Golden yellow, outstanding for fall color
Winter Color: Holds brown leaves throughout the winter
Bark: Grayish-brown with long horizontal strips
Habitat: Eastern half of the U.S.
Culture: Moist, acidic soil, does well in shade
Hardiness Zone: 4 – 9
Heat Zone: 7 – 5
Growth Rate: Full size in 30 years
Pest Resistance: Free of major pest problems, except for an occasional witches' broom
Storm Resistance: Excellent
Salt Resistance: Poor
Planting: Transplant B&B or container, very slow recovery bare root
Pruning: Seldom needs pruning Propagating: Grafted to seedlings or rooted cuttings made in winter
Design Uses: Excellent for naturalizing a street or residential landscape
Companions: Best with shade loving groundcovers and with native hophornbeams
Site Requirements: Full sun to partial shade
Other Comments: Ideal for naturalizing landscapes
Photo
Sources
This information has been gathered from personal observations of the author, living in Massachusetts, Zone 6 and information provided by J. Frank Schmidt & Son.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Len Phillips
Autumn Treasure Hophornbeam is a cultivar from a native hophornbeam also known as Ironwood and it is an ideal tree for naturalistic landscaping. Autumn Treasure Hophornbeam is suited for city living and has an upright narrow form that facilitates uniform street tree plantings.
Trade Name: Autumn Treasure® Hophornbeam
Botanical Name: Ostyra virginiana ‘JFS-KW5’
Family: Betulaceae
Parentage: Native species
Height: 30' - 40'
Spread: 20' - 25'
Form: Upright, narrow form
Flower: Small catkins, 1” long
Fruit: Nutlet is 1/2” long, resembles hops
Foliage: Serrated leaves
Spring Color: Pale yellowish-green flowers, stems and young leaves
Summer Foliage: Dark green
Autumn Foliage: Golden yellow, outstanding for fall color
Winter Color: Holds brown leaves throughout the winter
Bark: Grayish-brown with long horizontal strips
Habitat: Eastern half of the U.S.
Culture: Moist, acidic soil, does well in shade
Hardiness Zone: 4 – 9
Heat Zone: 7 – 5
Growth Rate: Full size in 30 years
Pest Resistance: Free of major pest problems, except for an occasional witches' broom
Storm Resistance: Excellent
Salt Resistance: Poor
Planting: Transplant B&B or container, very slow recovery bare root
Pruning: Seldom needs pruning Propagating: Grafted to seedlings or rooted cuttings made in winter
Design Uses: Excellent for naturalizing a street or residential landscape
Companions: Best with shade loving groundcovers and with native hophornbeams
Site Requirements: Full sun to partial shade
Other Comments: Ideal for naturalizing landscapes
Photo
Sources
This information has been gathered from personal observations of the author, living in Massachusetts, Zone 6 and information provided by J. Frank Schmidt & Son.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Tree Planting Decisions
By Len Phillips
When an arborist or urban forester is asked by the mayor, city council, or tree advisory board to recommend the best way to preserve or plant new trees in the city, how do you respond? The following can be considered the best options for planting trees or installing sidewalks in conjunction with construction activities around a city sidewalk in various site and sidewalk conditions.
⊙ SITE – NEW CONSTRUCTION INCLUDING NEW SIDEWALKS AND NEW TREES
Best Planting Option – During construction of new sidewalks, streets, utilities, and buildings – plant all the trees in groups 10 to 20 ft. (3 – 6m) apart or included shrub beds with excellent soil and growing conditions. Be sure to select trees that are not considered surface rooted trees. For lists of desirable trees, see the lists in the opening section of Topic #18.
Second Best Planting Option – The use of soil cells is the next best method for ensuring there is enough suitable soil for a tree to develop into a mature specimen. Soil cells transfer a compacted foundation 3 ft. (1 m) below grade to a surface suitable for a sidewalk, plaza, or light traffic roadway while allowing plenty of ideal soil for growing trees under the hard surface. The installation of root barriers to deflect roots downward should be included to prevent the tree's roots from causing damage to the surface pavement. The soil cells will also provide stormwater storage and reduce the frequency of manual watering of the newly planted trees. See Topic #18 - Soil Cells section for more information.
⊙ SITE – NEW SIDEWALKS AND PRESERVE EXISTING TREES
Best Option – Carefully examine the condition of the trees and the existing roots to provide care, protection, and root pruning as necessary. Modify the sidewalk design and location to accommodate the tree and its roots. This option is often the result of sidewalk replacements caused by roots that have damaged the existing sidewalks. The best and most common solution is to raise the sidewalk higher which results in the roots being in deeper soil than before the new sidewalk is installed. Include S-curves around the trees and pavement alternatives found in Topic #18 - Alternative Designs section.
Second Best Option – Loosen and improve the soil including that which will serve as a base for pavement. New sidewalks should be built and suspended on pilings above the tree roots or on the top of soil cells installed under the new sidewalk depending on the existing root locations. See Topic #18 - Suspended Pavements section for more information.
⊙ SITE – NEW TREES AND PRESERVE EXISTING TREES
Two Best Planting Options – Using an air tool, excavate as much soil as possible, under and around any existing roots, including the areas where the pavement is planned. Carefully examine the existing roots and prune if necessary. Follow the Stockholm Solution procedures of adding layers of large rock, washing soil into the voids between the rocks, adding another layer of rocks, and continuing this rock and soil process until the entire area that will become paved, is just below finished grade.
An option would be to install CU Structural Soil which consists of mixing one inch (2.5 cm) stone and soil together and installing this mix into the area to be paved. After completing either option, add any new trees and root barriers as necessary, before finishing the job with the addition of a new pavement on the surface. See Topic #5 - Successful Planting section for more information.
⊙ SITE – NEW TREES AND PRESERVE EXISTING SIDEWALKS
Best Planting Option – Consider relocating the planting site to the other side of the sidewalk, away from the curb and street, if the site is suitable and better soil is available. This assumes that the traffic volume and speed are not a pedestrian safety concern that might require trees as a safety barrier. This option may also require a local easement or agreement with the abutting land owner if the trees will be planted on private property. In cities where this option is approved, most of the maintenance of the tree is also transferred to the private land owner. See Topic #18 - Sidewalk Planning & Construction section for more information.
Second Best Planting Option – Excavate as much soil as possible for the tree planting site, to obtain 500 cu. ft. (14 cu meters) of space for installing good soil, include going as deep as 4 feet (125 cm). Punch, auger, or wash out holes from the bottom of the planting pit, under the sidewalk, toward good soil, if it is available beyond the sidewalk and let the tree's roots following the holes toward this better soil. Select a tree that is suitable for the amount of soil available. See Topic #18 Sidewalk Planning & Construction - Soil Volume section for more information. Plant the tree with excellent soil that is similar in texture to the existing soil around the planting pit.
⊙ SITE – NO TREES AND NO SIDEWALKS
Best Planting Option – All the planting options listed above are suitable. However, anticipate what the future might bring at this site and plant the appropriate tree at the appropriate site for the future. See Topic #18 for more information.
⊙ SITE – ROOT TREATMENT OPTIONS
Best Choice of Trees – Become familiar with how to plant bare root trees. They are the least costly to purchase and plant by contract and easiest to plant when using volunteers. Planting trees with bare roots in city soils will not delay their transition to different soils than what they were growing in at the nursery. See more information on planting bare root trees. If there is a concern that the lack of a soil ball might cause the tree to blow over, this is easily remedied with any of several root stabilizing options that are currently available. See more information on root stabilization in our Archived Seminar #70 - Staking New Trees section.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Len Phillips
When an arborist or urban forester is asked by the mayor, city council, or tree advisory board to recommend the best way to preserve or plant new trees in the city, how do you respond? The following can be considered the best options for planting trees or installing sidewalks in conjunction with construction activities around a city sidewalk in various site and sidewalk conditions.
⊙ SITE – NEW CONSTRUCTION INCLUDING NEW SIDEWALKS AND NEW TREES
Best Planting Option – During construction of new sidewalks, streets, utilities, and buildings – plant all the trees in groups 10 to 20 ft. (3 – 6m) apart or included shrub beds with excellent soil and growing conditions. Be sure to select trees that are not considered surface rooted trees. For lists of desirable trees, see the lists in the opening section of Topic #18.
Second Best Planting Option – The use of soil cells is the next best method for ensuring there is enough suitable soil for a tree to develop into a mature specimen. Soil cells transfer a compacted foundation 3 ft. (1 m) below grade to a surface suitable for a sidewalk, plaza, or light traffic roadway while allowing plenty of ideal soil for growing trees under the hard surface. The installation of root barriers to deflect roots downward should be included to prevent the tree's roots from causing damage to the surface pavement. The soil cells will also provide stormwater storage and reduce the frequency of manual watering of the newly planted trees. See Topic #18 - Soil Cells section for more information.
⊙ SITE – NEW SIDEWALKS AND PRESERVE EXISTING TREES
Best Option – Carefully examine the condition of the trees and the existing roots to provide care, protection, and root pruning as necessary. Modify the sidewalk design and location to accommodate the tree and its roots. This option is often the result of sidewalk replacements caused by roots that have damaged the existing sidewalks. The best and most common solution is to raise the sidewalk higher which results in the roots being in deeper soil than before the new sidewalk is installed. Include S-curves around the trees and pavement alternatives found in Topic #18 - Alternative Designs section.
Second Best Option – Loosen and improve the soil including that which will serve as a base for pavement. New sidewalks should be built and suspended on pilings above the tree roots or on the top of soil cells installed under the new sidewalk depending on the existing root locations. See Topic #18 - Suspended Pavements section for more information.
⊙ SITE – NEW TREES AND PRESERVE EXISTING TREES
Two Best Planting Options – Using an air tool, excavate as much soil as possible, under and around any existing roots, including the areas where the pavement is planned. Carefully examine the existing roots and prune if necessary. Follow the Stockholm Solution procedures of adding layers of large rock, washing soil into the voids between the rocks, adding another layer of rocks, and continuing this rock and soil process until the entire area that will become paved, is just below finished grade.
An option would be to install CU Structural Soil which consists of mixing one inch (2.5 cm) stone and soil together and installing this mix into the area to be paved. After completing either option, add any new trees and root barriers as necessary, before finishing the job with the addition of a new pavement on the surface. See Topic #5 - Successful Planting section for more information.
⊙ SITE – NEW TREES AND PRESERVE EXISTING SIDEWALKS
Best Planting Option – Consider relocating the planting site to the other side of the sidewalk, away from the curb and street, if the site is suitable and better soil is available. This assumes that the traffic volume and speed are not a pedestrian safety concern that might require trees as a safety barrier. This option may also require a local easement or agreement with the abutting land owner if the trees will be planted on private property. In cities where this option is approved, most of the maintenance of the tree is also transferred to the private land owner. See Topic #18 - Sidewalk Planning & Construction section for more information.
Second Best Planting Option – Excavate as much soil as possible for the tree planting site, to obtain 500 cu. ft. (14 cu meters) of space for installing good soil, include going as deep as 4 feet (125 cm). Punch, auger, or wash out holes from the bottom of the planting pit, under the sidewalk, toward good soil, if it is available beyond the sidewalk and let the tree's roots following the holes toward this better soil. Select a tree that is suitable for the amount of soil available. See Topic #18 Sidewalk Planning & Construction - Soil Volume section for more information. Plant the tree with excellent soil that is similar in texture to the existing soil around the planting pit.
⊙ SITE – NO TREES AND NO SIDEWALKS
Best Planting Option – All the planting options listed above are suitable. However, anticipate what the future might bring at this site and plant the appropriate tree at the appropriate site for the future. See Topic #18 for more information.
⊙ SITE – ROOT TREATMENT OPTIONS
Best Choice of Trees – Become familiar with how to plant bare root trees. They are the least costly to purchase and plant by contract and easiest to plant when using volunteers. Planting trees with bare roots in city soils will not delay their transition to different soils than what they were growing in at the nursery. See more information on planting bare root trees. If there is a concern that the lack of a soil ball might cause the tree to blow over, this is easily remedied with any of several root stabilizing options that are currently available. See more information on root stabilization in our Archived Seminar #70 - Staking New Trees section.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Parklets
Edited by Len Phillips
Parklets are becoming popular in urban planning. Parklets consist of converting 1 – 3 parking spaces along the edge of a city street, into very small parks. While a parking space is used by one or two people an hour, a parklet is being enjoyed by dozens of people all day long. They are funded by nearby businesses, but are open to everyone. In places where they have been built, they have become extremely popular and a major boost to abutting businesses. In instances where a parklet is not intended to accommodate people, it may provide greenery, art, or some other visual amenity. A parklet may accommodate bicycle parking within it, or associated with it.
History
Funding Sources
In almost all cases, business owners pay for the construction and maintenance of the parklets. They will vary in cost but the average is between US$15,000 and $20,000. In some cases the cities will offer design assistance or some funding. Other cities will donate the street tree that is a key feature in most parklets. Businesses are doing this to beautify their city block and help attract more foot traffic and encourage city funded improvements. Cites also see parklets as a low investment in innovative new public spaces.
Design Elements
The typical design is a platform that extends the sidewalk and provides amenities like seats, tables, bike racks, and landscaping.
Conclusion
What works in one city may not work in another. For example, parklets on the West Coast are open year-round, while those in Chicago and Philadelphia will be closed and removed for the winter. Cities are encouraged to experiment with what works and what doesn't.
Sources
· Artz, Matthew "'Parking spot to park in Oakland", Oakland Tribune, March 21, 2012
· Patton, Zach, “On-Street Parking”, Governing Magazine. June 2012.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
Parklets are becoming popular in urban planning. Parklets consist of converting 1 – 3 parking spaces along the edge of a city street, into very small parks. While a parking space is used by one or two people an hour, a parklet is being enjoyed by dozens of people all day long. They are funded by nearby businesses, but are open to everyone. In places where they have been built, they have become extremely popular and a major boost to abutting businesses. In instances where a parklet is not intended to accommodate people, it may provide greenery, art, or some other visual amenity. A parklet may accommodate bicycle parking within it, or associated with it.
History
- In 2005, San Francisco was the first city to convert a parking space to a park with sod, benches, and trees on a temporary basis. The abutting store owner had to feed the meter and remove the park features annually, during the winter/rainy season. This was followed in 2009, when New York City began converting several street spaces into pedestrian-only plazas.
- In 2010, San Francisco recognized the original parklet's significance and removed the meter. They also established the first permanent parklet. They currently have 27 parklets functioning with 40 more in the planning stage.
- In February 2013, the San Francisco Planning Department published a Parklet Manual which served as a comprehensive overview of the goals, policies, process, procedures, and guidelines for creating parklets in San Francisco. The Manual also serves as a resource for those outside of San Francisco working to establish parklet programs in their own cities.
- Parklets have sprung up in many other cities including Phoenix, Philadelphia, Dallas, Roanoke VA, Seattle, Chicago, and New York City. Parklets have become very popular in California and can be found in Los Angeles, San Jose, Oakland, San Diego, Morro Bay, and Long Beach in addition to San Francisco. Long Beach is planning to create 'Bio-soil” parklets intended to help capture and divert
rainwater. - Outside of the US, parklets have been installed in Victoria and Vancouver, British Columbia, London, Adelaide, South Australia, and in Mexico at Puebla de Zaragoza during the Puebla Design Fest
Funding Sources
In almost all cases, business owners pay for the construction and maintenance of the parklets. They will vary in cost but the average is between US$15,000 and $20,000. In some cases the cities will offer design assistance or some funding. Other cities will donate the street tree that is a key feature in most parklets. Businesses are doing this to beautify their city block and help attract more foot traffic and encourage city funded improvements. Cites also see parklets as a low investment in innovative new public spaces.
Design Elements
The typical design is a platform that extends the sidewalk and provides amenities like seats, tables, bike racks, and landscaping.
- Parklets work best in front of a business that offers food or entertainment and needs walk-up customers.
- They need to be on streets with low speed limits.
- They must not be placed at street corners.
- They should be visually distinctive.
- Trees are encouraged in all permanent parklets because they can be given extra soil space under the entire parklet for proper root growth.
- The benches and chairs in one parklet must look different from any seating at the adjacent business and other parklets to reinforce the idea that these are public spaces rather than an extension of a private café.
- Benches in the parklet must be built-in rather than movable chairs and tables.
- Cafes are not allowed to serve customers sitting in the parklets.
- Each parklet should average at least 320 square feet (30 sm) in size.
- The design should be simple and inexpensive.
- The parklets can be issued an annual permit so if it doesn't work it can be restored to a car parking space.
Conclusion
What works in one city may not work in another. For example, parklets on the West Coast are open year-round, while those in Chicago and Philadelphia will be closed and removed for the winter. Cities are encouraged to experiment with what works and what doesn't.
Sources
· Artz, Matthew "'Parking spot to park in Oakland", Oakland Tribune, March 21, 2012
· Patton, Zach, “On-Street Parking”, Governing Magazine. June 2012.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Red-Leaf Crabapple Cultivars
By Len Phillips
Crabapples are known for their early summer flowers and many are also known for their red fruits that persist throughout the winter. In addition to these desirable features, most crabapples have green leaves. However, red-leafed trees have become very popular especially on crabapples. Here are the common features of all crabapples.
Common Name: Crabapple
Botanical Name: Malus species
Family: Rosaceae
Parentage: Native
Bark: Dark brown or gray
Habitat: Does very well throughout the U.S.
Culture: Well drained acidic soil
Heat Zone: 8 – 1
USDA Hardiness Zone: Varies according to cultivar, see below
Growth Rate: Medium, full size in 25 years
Storm Resistance: Good
Salt Resistance: Good
Planting: Fibrous roots allow any transplanting technique, including bare root, in spring
only, does well in CU-Structural Soil planting
Pruning: Prune at planting and 3 years later to mature form
Propagating: Root stock can be standard, Dolgo crabapple seedlings for cold hardiness, or RightRoot™ crabapple rootstock that produce very few suckers
Design Uses: Excellent for residential, park, and open spaces, as well as under utility wires
Companions: Does well with most perennial groundcovers and other crabapples
Site Requirements: Likes most sites with moist soils and almost full sun
Other Comments: Dense leaves, vigorous growers, very popular trees
The best and most popular red or purple leafed crabapples, in this author's opinion, are:
Cardinal crabapple Malus ‘Cardinal’ - USDA Hardiness Zone 4 – 8; Height: 16'; Spread: 22'; Shape: broadly spreading; Foliage: dark purple-red, glossy; Flower: bright pinkish-red; Fruit: deep red, 1⁄2" in diameter.
Disease Resistance:
Scab – Excellent
Fireblight – Good
Cedar-Apple Rust – Excellent
Mildew – Excellent
Cardinal holds its deep purple leaf color through the summer and has one of the best resistance to the
diseases listed above. Photo
Perfect Purple crabapple Malus ‘Perfect Purple’ - USDA Hardiness Zone 3 – 8; Height: 20'; Spread: 20'; Shape: rounded; Foliage: deep purple; Fall Color: purple; Flower: deep pink to rose red; Fruit: purple red.
Disease Resistance:
Scab – Fair
Fireblight – Fair
Cedar-Apple Rust – Good
Mildew – Excellent
Deep pink blooms contrast nicely with the dark purple foliage on a very attractive tree. This crab has performed well in the colder regions of northern US and the Inter-Mountain regions. Photo
Pink Princess crabapple Malus ‘Parrsi’ - USDA Hardiness Zone 5 – 8; Height: 8'; Spread: 12'; Shape: low, spreading: Foliage: purple, becoming bronze green; Flower: rose pink; Fruit: deep red, 1⁄4" in diameter.
Disease Resistance:
Scab – Excellent
Fireblight – Excellent
Cedar-Apple Rust – Excellent
Mildew – Excellent
This is a naturally dwarf tree and in a new color. Pink Princess has the best disease resistance of all the crabs listed here. It is also more tolerant of hot weather than other crabapples. Photo
Radiant crabapple Malus 'Radiant' - USDA Hardiness Zone 3 – 8; height 25'; Spread 20'; Shape – broad, rounded crown, Foliage: new leaves red-purple, mature to bronze green, Flower: deep red buds, single pink bloom, Fruit: bright red 1/2” in diameter.
Disease Resistance:
Scab – Poor
Fireblight – Excellent
Cedar-Apple Rust – Good
Mildew – Fair
A University of Minnesota introduction selected for cold hardiness and it performs well in the western mountains of the US. Photo
Red Barron crabapple Malus ‘Red Barron’ - USDA Hardiness Zone 4 – 8; Height: 18'; Spread: 8'; Shape: narrow, upright; Foliage: purple, maturing to bronze-green; Flower: dark red; Fruit: dark red, 1⁄2” in diameter.
Disease Resistance:
Scab – Fair
Fireblight – Good
Cedar-Apple Rust – Excellent
Mildew – Excellent
The ascending branch structure and adaptability to urban conditions make Red Barron an excellent urban tree.
Photo
Royal Raindrops crabapple Malus ‘JFS-KW5’ PP 14375 - USDA Hardiness Zone 4 – 8; Height: 20'; Spread: 15'; Shape: spreading; Foliage: cutleaf purple; Fall Color: orange-red; Flower: bright pinkish red; Fruit: Red, 1⁄4" in diameter, persistent over winter.
Disease Resistance:
Scab – Excellent
Fireblight – Good
Cedar-Apple Rust – Excellent
Mildew – Good
Deeply lobed leaves and upright form with good branching and density. Growth is outstanding. Photo
Royalty crabapple Malus ‘Royalty’ - USDA Hardiness Zone 4 – 8; Height: 15'; Spread: 15'; Shape: rounded; Foliage: purple, glossy; Flower: single, purple to crimson; Fruit: dark red, 5/8"-3/4" in diameter.
Disease Resistance:
Scab – Poor
Cedar-Apple Rust – Excellent
Mildew – Excellent
Fireblight – Fair
Flowers are almost the same color as the leaves. Photo
Show Time crabapple Malus ‘Shotizam’ - USDA Hardiness Zone 4 – 8; Height: 22'; Spread: 20'; Shape: broadly oval to round; Foliage: purple bronze to bronze green; Flower: bright pinkish red; Fruit: red, 1⁄2” in diameter, persistent.
Disease Resistance:
Scab – Fair
Fireblight – Good
Cedar-Apple rust – Good
Mildew – Excellent
Show Time is a heavy bloomer of large flowers that produce many fruits in autumn. Photo
Velvet Pillar crabapple Malus 'Velvetcole' PP# 4758 – USDA Hardiness Zone 4 – 7; Height 20'; Spread 14'; Shape: oval head with ascending branches; Foliage: purple; Flower: pink, single; Fruit: sparse, maroon-red, 3/8” in diameter.
Disease resistance:
Scab – Fair
Fireblight – Good
Cedar-apple rust – Excellent
Mildew – Good
Velvet Pillar's flower buds emerge red and open to rosy pink flowers. They are followed by unusual purple foliage that has a velvety look when it unfurls. This crab is notable for its upright form and dense branching habit, and is useful for confined planting spaces. 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 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Len Phillips
Crabapples are known for their early summer flowers and many are also known for their red fruits that persist throughout the winter. In addition to these desirable features, most crabapples have green leaves. However, red-leafed trees have become very popular especially on crabapples. Here are the common features of all crabapples.
Common Name: Crabapple
Botanical Name: Malus species
Family: Rosaceae
Parentage: Native
Bark: Dark brown or gray
Habitat: Does very well throughout the U.S.
Culture: Well drained acidic soil
Heat Zone: 8 – 1
USDA Hardiness Zone: Varies according to cultivar, see below
Growth Rate: Medium, full size in 25 years
Storm Resistance: Good
Salt Resistance: Good
Planting: Fibrous roots allow any transplanting technique, including bare root, in spring
only, does well in CU-Structural Soil planting
Pruning: Prune at planting and 3 years later to mature form
Propagating: Root stock can be standard, Dolgo crabapple seedlings for cold hardiness, or RightRoot™ crabapple rootstock that produce very few suckers
Design Uses: Excellent for residential, park, and open spaces, as well as under utility wires
Companions: Does well with most perennial groundcovers and other crabapples
Site Requirements: Likes most sites with moist soils and almost full sun
Other Comments: Dense leaves, vigorous growers, very popular trees
The best and most popular red or purple leafed crabapples, in this author's opinion, are:
Cardinal crabapple Malus ‘Cardinal’ - USDA Hardiness Zone 4 – 8; Height: 16'; Spread: 22'; Shape: broadly spreading; Foliage: dark purple-red, glossy; Flower: bright pinkish-red; Fruit: deep red, 1⁄2" in diameter.
Disease Resistance:
Scab – Excellent
Fireblight – Good
Cedar-Apple Rust – Excellent
Mildew – Excellent
Cardinal holds its deep purple leaf color through the summer and has one of the best resistance to the
diseases listed above. Photo
Perfect Purple crabapple Malus ‘Perfect Purple’ - USDA Hardiness Zone 3 – 8; Height: 20'; Spread: 20'; Shape: rounded; Foliage: deep purple; Fall Color: purple; Flower: deep pink to rose red; Fruit: purple red.
Disease Resistance:
Scab – Fair
Fireblight – Fair
Cedar-Apple Rust – Good
Mildew – Excellent
Deep pink blooms contrast nicely with the dark purple foliage on a very attractive tree. This crab has performed well in the colder regions of northern US and the Inter-Mountain regions. Photo
Pink Princess crabapple Malus ‘Parrsi’ - USDA Hardiness Zone 5 – 8; Height: 8'; Spread: 12'; Shape: low, spreading: Foliage: purple, becoming bronze green; Flower: rose pink; Fruit: deep red, 1⁄4" in diameter.
Disease Resistance:
Scab – Excellent
Fireblight – Excellent
Cedar-Apple Rust – Excellent
Mildew – Excellent
This is a naturally dwarf tree and in a new color. Pink Princess has the best disease resistance of all the crabs listed here. It is also more tolerant of hot weather than other crabapples. Photo
Radiant crabapple Malus 'Radiant' - USDA Hardiness Zone 3 – 8; height 25'; Spread 20'; Shape – broad, rounded crown, Foliage: new leaves red-purple, mature to bronze green, Flower: deep red buds, single pink bloom, Fruit: bright red 1/2” in diameter.
Disease Resistance:
Scab – Poor
Fireblight – Excellent
Cedar-Apple Rust – Good
Mildew – Fair
A University of Minnesota introduction selected for cold hardiness and it performs well in the western mountains of the US. Photo
Red Barron crabapple Malus ‘Red Barron’ - USDA Hardiness Zone 4 – 8; Height: 18'; Spread: 8'; Shape: narrow, upright; Foliage: purple, maturing to bronze-green; Flower: dark red; Fruit: dark red, 1⁄2” in diameter.
Disease Resistance:
Scab – Fair
Fireblight – Good
Cedar-Apple Rust – Excellent
Mildew – Excellent
The ascending branch structure and adaptability to urban conditions make Red Barron an excellent urban tree.
Photo
Royal Raindrops crabapple Malus ‘JFS-KW5’ PP 14375 - USDA Hardiness Zone 4 – 8; Height: 20'; Spread: 15'; Shape: spreading; Foliage: cutleaf purple; Fall Color: orange-red; Flower: bright pinkish red; Fruit: Red, 1⁄4" in diameter, persistent over winter.
Disease Resistance:
Scab – Excellent
Fireblight – Good
Cedar-Apple Rust – Excellent
Mildew – Good
Deeply lobed leaves and upright form with good branching and density. Growth is outstanding. Photo
Royalty crabapple Malus ‘Royalty’ - USDA Hardiness Zone 4 – 8; Height: 15'; Spread: 15'; Shape: rounded; Foliage: purple, glossy; Flower: single, purple to crimson; Fruit: dark red, 5/8"-3/4" in diameter.
Disease Resistance:
Scab – Poor
Cedar-Apple Rust – Excellent
Mildew – Excellent
Fireblight – Fair
Flowers are almost the same color as the leaves. Photo
Show Time crabapple Malus ‘Shotizam’ - USDA Hardiness Zone 4 – 8; Height: 22'; Spread: 20'; Shape: broadly oval to round; Foliage: purple bronze to bronze green; Flower: bright pinkish red; Fruit: red, 1⁄2” in diameter, persistent.
Disease Resistance:
Scab – Fair
Fireblight – Good
Cedar-Apple rust – Good
Mildew – Excellent
Show Time is a heavy bloomer of large flowers that produce many fruits in autumn. Photo
Velvet Pillar crabapple Malus 'Velvetcole' PP# 4758 – USDA Hardiness Zone 4 – 7; Height 20'; Spread 14'; Shape: oval head with ascending branches; Foliage: purple; Flower: pink, single; Fruit: sparse, maroon-red, 3/8” in diameter.
Disease resistance:
Scab – Fair
Fireblight – Good
Cedar-apple rust – Excellent
Mildew – Good
Velvet Pillar's flower buds emerge red and open to rosy pink flowers. They are followed by unusual purple foliage that has a velvety look when it unfurls. This crab is notable for its upright form and dense branching habit, and is useful for confined planting spaces. 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 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Air Pollution Damage
Edited by Len Phillips
Air pollution damage occurs when certain air pollutants reach levels that cause health problems for plants and people.
Damage to Plants
Air pollution damage often appears as yellowing or flecking of the leaves. Often the foliage may be thin or stunted. On broad leaved trees the damage is seen as an interveinal or marginal chlorosis or necrosis similar to leaf scorch. The veins frequently remain green. These symptoms will vary according to environmental conditions, the season, and the amount and length of exposure.
Weather Conditions
Air pollution damage is commonly associated with late spring and summer high pressure weather patterns during which the temperature and humidity frequently exceed 90° F (34°C) and 90% respectively. They are also associated with temperature inversions when a band of warm air forms in the normally cool upper level of the atmosphere. This prevents the upper movement of pollutants and instead concentrates them close to the earth's surface where they can cause harm to plants and trees.
During these episodes, ozone and sulfur dioxide can accumulate to concentrations in the air that will damage trees, shrubs, and other plants. A number of other air contaminants such as fluoride, ethylene, and chlorine can also damage plants, but this happens infrequently and is usually localized.
Ozone
Ozone (O3) is a photo-chemical pollutant (requires light for its formation) formed by a reaction between nitrogen oxides and hydrocarbons coming largely from car exhaust and industries. It is the most widely spread air pollutant in the US. Typical damage patterns can be seen in many parts of the country.
Acute symptoms vary from stippling, flecking, and bleaching to dead areas on plants. Symptoms on broad-leaves are typically very small yellow flecks or stipples smaller than the size of a pinhead on the upper leaf surface. Ozone seldom damages the lower leaf surface. These distinct flecks can coalesce to form large yellow, tan, or reddish areas covering a good portion of the leaf. The leaves will then drop prematurely. Leaves which develop after an ozone episode, will not be symptomatic. This can help in diagnosing damage especially in the spring and early summer during active growth. Chronic damage develops more slowly over days or weeks. Symptoms are often more severe on leaves that are exposed to direct sunlight. Newly expanded leaves are most sensitive. The symptoms may fade after several weeks. See Photo
Sulfur Dioxide
Sulfur dioxide (SO2) originates primarily from fossil fuel combustion during the generation of electricity, refining, and ore smelting. Sulfur dioxide enters plants along with normal air components moving into the leaves. However, the sulfur dioxide reacts with cells inside of the leaf. Symptom expression can take as little as one day to develop. Sulfur dioxide damage on oaks appear as ivory to brown intervienal necrosis. Uninjured tissue next to the veins remains green. Affected leaves may exhibit spots or patches of papery thin almost transparent tissues. See Photo
Damage on Evergreen Needles
Mottled green and yellow patches or yellow bands of tissue on the evergreen needle surface usually indicate chronic ozone damage on conifers. Ozone damage is first seen at the tips but can eventually cover the entire needle. The yellow patches or bands can coalesce forming a completely yellow tip while more yellow patches form closer to the base of the needle. Frequently, some needles on a branch will be entirely covered with chlorotic blotches while others are green with only a slight yellowing at the tip. Last season’s needles can prematurely drop from the tree during the summer. If ozone concentrations are high or if the tree is particularly sensitive, the tip or the entire needle will turn brown and die. This is classed as acute damage. See Photo
Yellowing usually occurs when trees are exposed to low doses of ozone and tip burn appears from exposure to high doses. This tip browning results from necrotic banding of medium aged tissue along the middle of the needles, which is the most sensitive area of the needle. Tip burn symptoms affect most of the needles equally on a branch. These dead needle tips may also break off over time giving the appearance of shorter than normal needles.
Sulfur dioxide damage on young needles appears as reddish brown needle tips, but later in the season may appear as bands of necrotic tissue on the needles. Injured needles may remain on the plant for some time. In more severe cases, a tan to reddish-brown discoloration indicating death to all or a portion of the needle. The injured portion may at first be restricted to the tip or base of the needle.
Other Damages
Many factors in the environment cause tree symptoms, which copy those caused by specific air pollutants.
Prevention
Fertilizing trees can make them less susceptible to further damage from sulfur dioxide and ozone. But keeping a plant healthy with proper maintenance and nutrition is just as important. If the plant is already sick, and is then exposed to pollutants, it may not be healthy enough to uptake the fertilizer, thus forcing growth at the expense of health. In areas with chronic high concentrations of pollutants, consider planting species from the list below which are tolerant to the local pollutants.
Trees Tolerant to Air Pollutants
Tree species, varieties, cultivars, and individuals within a species react differently to the different air pollutants. For example, white pine (Pinus strobus) is highly sensitive to ozone and sulfur dioxide pollution, but there are individual trees that are more resistant than so-called “pollution resistant” species. This is true of other species as well.
Species generally quite tolerant of ambient ozone concentrations:
Acer, maples
Betula, birches
Gleditsia, honeylocust
Quercus, oaks
Trees generally tolerant of sulfur dioxide pollution:
Acer saccharinum Silver maple
Acer saccharum Sugar maple
Ginkgo biloba Ginkgo
Juniperus spp. Juniper
Picea pungens Blue spruce
Quercus palustris Pin oak
Quercus rubra Red oak
Thuja spp. Arborvitae
Tilia cordata Littleleaf linden
Taxodium distichum Common Bald cypress
Sources
· University of Maryland, College of Agriculture and Natural Resources, “Air Pollution Damage - Trees
and Shrubs”, 2016
· Smiley, E. Thomas PhD, “ Air Pollution Injury to Landscape Plants - Identification and Treatment”,
Bartlett Tree Experts
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
Air pollution damage occurs when certain air pollutants reach levels that cause health problems for plants and people.
Damage to Plants
Air pollution damage often appears as yellowing or flecking of the leaves. Often the foliage may be thin or stunted. On broad leaved trees the damage is seen as an interveinal or marginal chlorosis or necrosis similar to leaf scorch. The veins frequently remain green. These symptoms will vary according to environmental conditions, the season, and the amount and length of exposure.
Weather Conditions
Air pollution damage is commonly associated with late spring and summer high pressure weather patterns during which the temperature and humidity frequently exceed 90° F (34°C) and 90% respectively. They are also associated with temperature inversions when a band of warm air forms in the normally cool upper level of the atmosphere. This prevents the upper movement of pollutants and instead concentrates them close to the earth's surface where they can cause harm to plants and trees.
During these episodes, ozone and sulfur dioxide can accumulate to concentrations in the air that will damage trees, shrubs, and other plants. A number of other air contaminants such as fluoride, ethylene, and chlorine can also damage plants, but this happens infrequently and is usually localized.
Ozone
Ozone (O3) is a photo-chemical pollutant (requires light for its formation) formed by a reaction between nitrogen oxides and hydrocarbons coming largely from car exhaust and industries. It is the most widely spread air pollutant in the US. Typical damage patterns can be seen in many parts of the country.
Acute symptoms vary from stippling, flecking, and bleaching to dead areas on plants. Symptoms on broad-leaves are typically very small yellow flecks or stipples smaller than the size of a pinhead on the upper leaf surface. Ozone seldom damages the lower leaf surface. These distinct flecks can coalesce to form large yellow, tan, or reddish areas covering a good portion of the leaf. The leaves will then drop prematurely. Leaves which develop after an ozone episode, will not be symptomatic. This can help in diagnosing damage especially in the spring and early summer during active growth. Chronic damage develops more slowly over days or weeks. Symptoms are often more severe on leaves that are exposed to direct sunlight. Newly expanded leaves are most sensitive. The symptoms may fade after several weeks. See Photo
Sulfur Dioxide
Sulfur dioxide (SO2) originates primarily from fossil fuel combustion during the generation of electricity, refining, and ore smelting. Sulfur dioxide enters plants along with normal air components moving into the leaves. However, the sulfur dioxide reacts with cells inside of the leaf. Symptom expression can take as little as one day to develop. Sulfur dioxide damage on oaks appear as ivory to brown intervienal necrosis. Uninjured tissue next to the veins remains green. Affected leaves may exhibit spots or patches of papery thin almost transparent tissues. See Photo
Damage on Evergreen Needles
Mottled green and yellow patches or yellow bands of tissue on the evergreen needle surface usually indicate chronic ozone damage on conifers. Ozone damage is first seen at the tips but can eventually cover the entire needle. The yellow patches or bands can coalesce forming a completely yellow tip while more yellow patches form closer to the base of the needle. Frequently, some needles on a branch will be entirely covered with chlorotic blotches while others are green with only a slight yellowing at the tip. Last season’s needles can prematurely drop from the tree during the summer. If ozone concentrations are high or if the tree is particularly sensitive, the tip or the entire needle will turn brown and die. This is classed as acute damage. See Photo
Yellowing usually occurs when trees are exposed to low doses of ozone and tip burn appears from exposure to high doses. This tip browning results from necrotic banding of medium aged tissue along the middle of the needles, which is the most sensitive area of the needle. Tip burn symptoms affect most of the needles equally on a branch. These dead needle tips may also break off over time giving the appearance of shorter than normal needles.
Sulfur dioxide damage on young needles appears as reddish brown needle tips, but later in the season may appear as bands of necrotic tissue on the needles. Injured needles may remain on the plant for some time. In more severe cases, a tan to reddish-brown discoloration indicating death to all or a portion of the needle. The injured portion may at first be restricted to the tip or base of the needle.
Other Damages
Many factors in the environment cause tree symptoms, which copy those caused by specific air pollutants.
- High temperatures and dry soil cause leaf scorch symptoms which resemble fluoride or sulfur dioxide damage.
- Drought damage on conifers may resemble needle browning caused by various pollutants.
- Winter damage on broadleaf evergreens is displayed as marginal chlorosis and necrosis, which also resembles sulfur dioxide or fluoride damage.
- Some nutrient deficiency symptoms show up as chlorosis between the veins whereas other deficiencies appear as a general leaf chlorosis, similar to symptoms of low level, chronic exposure to an air pollutant.
- Insects such as mites, aphids and leaf hoppers cause leaf symptoms nearly identical to those due to ozone.
- Pesticides used to control fungi or insects may themselves cause damage to trees, which resemble air pollution damage.
Prevention
Fertilizing trees can make them less susceptible to further damage from sulfur dioxide and ozone. But keeping a plant healthy with proper maintenance and nutrition is just as important. If the plant is already sick, and is then exposed to pollutants, it may not be healthy enough to uptake the fertilizer, thus forcing growth at the expense of health. In areas with chronic high concentrations of pollutants, consider planting species from the list below which are tolerant to the local pollutants.
Trees Tolerant to Air Pollutants
Tree species, varieties, cultivars, and individuals within a species react differently to the different air pollutants. For example, white pine (Pinus strobus) is highly sensitive to ozone and sulfur dioxide pollution, but there are individual trees that are more resistant than so-called “pollution resistant” species. This is true of other species as well.
Species generally quite tolerant of ambient ozone concentrations:
Acer, maples
Betula, birches
Gleditsia, honeylocust
Quercus, oaks
Trees generally tolerant of sulfur dioxide pollution:
Acer saccharinum Silver maple
Acer saccharum Sugar maple
Ginkgo biloba Ginkgo
Juniperus spp. Juniper
Picea pungens Blue spruce
Quercus palustris Pin oak
Quercus rubra Red oak
Thuja spp. Arborvitae
Tilia cordata Littleleaf linden
Taxodium distichum Common Bald cypress
Sources
· University of Maryland, College of Agriculture and Natural Resources, “Air Pollution Damage - Trees
and Shrubs”, 2016
· Smiley, E. Thomas PhD, “ Air Pollution Injury to Landscape Plants - Identification and Treatment”,
Bartlett Tree Experts
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Determine the Value of Green Space
Edited by Len Phillips
Not all green spaces are equally green. By counting the birds in a green space, researchers can determine which green spaces have richer ecosystems. They also found that the number of birds on a given plot of land not only indicate eco-diversity, they also relate to property values. A survey in Texas counted birds near recently sold properties and discovered that a single additional bird species in a nearby green space could add about US $32,000 to a home's value compared to a similar house in a similar area, but with fewer birds. Higher home values related to more economic development which means higher property tax revenues and sales taxes. The study also showed that a more diverse bird population predicted a more diverse tree canopy as well as a total species diversity.
This information should result in a new way to think about building and managing urban parks and the urban forest. Improving landscape diversity, and thereby increasing birds and other urban wildlife populations, will lead to increasing real estate value.
For birds in urban environments, the configuration of local habitat within the landscape may be as critical as the composition of the local habitat itself. Habitat features such as large coniferous trees, berry-producing shrubs, and freshwater streams are of particular importance in estimating the likelihood of finding more bird species. In other words, diversity of habitat features, such as water, shelter, and food producing plants, is more important than total green space area.
Creating Diversity
Beyond increasing property values and wildlife habitat, the Texas researchers found that adding a diversity of landscape materials can cut street-level nitrogen dioxide and microscopic particulate matter, the two worst forms of pollution, by eight times more than previously thought. Many urban streets have high levels of these types of pollution, far exceeding healthy amounts for humans. Street trees, which have up to a 30% mortality rate in big cities, need better treatment if they are going to work effectively to contribute toward a diverse landscape.
Open land, parks, and abandoned properties have been completely reforested in some instances. Such patches of forest, however small, provide critical sources of oxygen and habitat enclaves within an otherwise artificial environment.
Neighborhood pocket parks managed by community associations provide sanctuaries from the noise and chaos of the busy city. These wonderful corners offer shade trees, shrubbery beds, flowers and bulbs, as well as a place to sit and enjoy the cool, green scenery right in the heart of the city. Pocket parks may be connected to larger parks by a common creek or stream, a heavily vegetated tree lawn or boulevard, forming greenways that can be enjoyed by cyclists and joggers, as well as birds and other wildlife.
Parks and Vacant Lots
Some ways to improve landscape diversity in parks or vacant lots include:
· planting trees to help improve diversity. Trees should be planted in small clumps related to buildings so
as not to impact views,
· creating wetland habitats, which help clean water,
· utilizing and improving stormwater management projects.
· introducing a variety of land covers, including open areas, areas with trees, areas with shrubs and
grasses, and areas with water features.
· enhancing public gardens with items such as containerized trees and shrubs, bulbs in pots, vegetable
plants and herbs in tubs, small water gardens, and wall gardens suitable for small spaces.
· planting groundcovers to provide an alternative to larger plants, and offer a number of color and texture
in both evergreen and deciduous varieties. Ground covers work well in hard-to-reach areas. Once
established, they require very little maintenance.
Private Properties
Encourage residents to enhance the landscape diversity on their private properties by adding:
Water
Water also attracts wildlife. Water gardens can consist of just about anything that introduces water into a landscape such as wetlands, ponds, fountains, barrels of water, a bird bath, or a waterlily tub. Splashing water can provide a much-needed respite on a hot day for songbirds who find the sounds and cool surface irresistible. A small wooden barrel or even a plastic tub can bring life to a colony of waterlilies, complete with small fish or maybe a frog or two.
Street Trees
Street trees provide not only wonderful shade and cool resting spots, but also generous amounts of oxygen to help keep the air clean and clear. Tall trees help to visually break up the urban skyline and introduce a textural softening to streets and buildings. Trees unite people in a neighborhood by providing a sense of identity, especially when they are planted together to define a specific area, such as a landscaped boulevard in a residential neighborhood.
A way to improve landscape diversity around street trees include changing the open ground at a tree's sidewalk opening into a small garden plot for living mulches of shade-loving plants, ground covers, and bulbs. The grass strips between the sidewalk and street provide a unique gardening opportunity, assuming that local government regulations do not forbid such activity. Many a flower garden has found its way into these places, adding a splash of color and wildlife habitat to an otherwise dull street scene. The median strip in the middle of a broad avenue provides a major opportunity for landscape diversity, color, and texture when planted with trees, shrubs, and flowers.
Forest cover and park areas significantly improve the diversity and distribution of birds in urban areas. Parks, reserves, and the surrounding residential areas should be integrated into urban planning and development designs to maintain resident bird life and overall species diversity in urban environments.
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 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
Not all green spaces are equally green. By counting the birds in a green space, researchers can determine which green spaces have richer ecosystems. They also found that the number of birds on a given plot of land not only indicate eco-diversity, they also relate to property values. A survey in Texas counted birds near recently sold properties and discovered that a single additional bird species in a nearby green space could add about US $32,000 to a home's value compared to a similar house in a similar area, but with fewer birds. Higher home values related to more economic development which means higher property tax revenues and sales taxes. The study also showed that a more diverse bird population predicted a more diverse tree canopy as well as a total species diversity.
This information should result in a new way to think about building and managing urban parks and the urban forest. Improving landscape diversity, and thereby increasing birds and other urban wildlife populations, will lead to increasing real estate value.
For birds in urban environments, the configuration of local habitat within the landscape may be as critical as the composition of the local habitat itself. Habitat features such as large coniferous trees, berry-producing shrubs, and freshwater streams are of particular importance in estimating the likelihood of finding more bird species. In other words, diversity of habitat features, such as water, shelter, and food producing plants, is more important than total green space area.
Creating Diversity
Beyond increasing property values and wildlife habitat, the Texas researchers found that adding a diversity of landscape materials can cut street-level nitrogen dioxide and microscopic particulate matter, the two worst forms of pollution, by eight times more than previously thought. Many urban streets have high levels of these types of pollution, far exceeding healthy amounts for humans. Street trees, which have up to a 30% mortality rate in big cities, need better treatment if they are going to work effectively to contribute toward a diverse landscape.
Open land, parks, and abandoned properties have been completely reforested in some instances. Such patches of forest, however small, provide critical sources of oxygen and habitat enclaves within an otherwise artificial environment.
Neighborhood pocket parks managed by community associations provide sanctuaries from the noise and chaos of the busy city. These wonderful corners offer shade trees, shrubbery beds, flowers and bulbs, as well as a place to sit and enjoy the cool, green scenery right in the heart of the city. Pocket parks may be connected to larger parks by a common creek or stream, a heavily vegetated tree lawn or boulevard, forming greenways that can be enjoyed by cyclists and joggers, as well as birds and other wildlife.
Parks and Vacant Lots
Some ways to improve landscape diversity in parks or vacant lots include:
· planting trees to help improve diversity. Trees should be planted in small clumps related to buildings so
as not to impact views,
· creating wetland habitats, which help clean water,
· utilizing and improving stormwater management projects.
· introducing a variety of land covers, including open areas, areas with trees, areas with shrubs and
grasses, and areas with water features.
· enhancing public gardens with items such as containerized trees and shrubs, bulbs in pots, vegetable
plants and herbs in tubs, small water gardens, and wall gardens suitable for small spaces.
· planting groundcovers to provide an alternative to larger plants, and offer a number of color and texture
in both evergreen and deciduous varieties. Ground covers work well in hard-to-reach areas. Once
established, they require very little maintenance.
Private Properties
Encourage residents to enhance the landscape diversity on their private properties by adding:
- potted vines including beans, peas, root crops, vine crops, fruit trees, and grapes,
- hanging flower baskets that are mixed with hanging bird feeders,
- window boxes containing herbs for kitchen use,
- diverse color and shapes through plant stands that create a privacy wall,
- shade gardens nestled beneath an overhang wooden lattice or a trellis, or in the shade of a large tree,
- wall gardens can be easily created by using hanging plants, some wall figures, a trellis of vines, ground covers, or climbing vegetable plants, and a small water spout from any available bare wall,
- intensive vegetable gardening as a method of growing vegetables and flowers together in relatively small spaces,
- large shrubbery and small tree plantings to screen out objectionable views and sounds.
Water
Water also attracts wildlife. Water gardens can consist of just about anything that introduces water into a landscape such as wetlands, ponds, fountains, barrels of water, a bird bath, or a waterlily tub. Splashing water can provide a much-needed respite on a hot day for songbirds who find the sounds and cool surface irresistible. A small wooden barrel or even a plastic tub can bring life to a colony of waterlilies, complete with small fish or maybe a frog or two.
Street Trees
Street trees provide not only wonderful shade and cool resting spots, but also generous amounts of oxygen to help keep the air clean and clear. Tall trees help to visually break up the urban skyline and introduce a textural softening to streets and buildings. Trees unite people in a neighborhood by providing a sense of identity, especially when they are planted together to define a specific area, such as a landscaped boulevard in a residential neighborhood.
A way to improve landscape diversity around street trees include changing the open ground at a tree's sidewalk opening into a small garden plot for living mulches of shade-loving plants, ground covers, and bulbs. The grass strips between the sidewalk and street provide a unique gardening opportunity, assuming that local government regulations do not forbid such activity. Many a flower garden has found its way into these places, adding a splash of color and wildlife habitat to an otherwise dull street scene. The median strip in the middle of a broad avenue provides a major opportunity for landscape diversity, color, and texture when planted with trees, shrubs, and flowers.
Forest cover and park areas significantly improve the diversity and distribution of birds in urban areas. Parks, reserves, and the surrounding residential areas should be integrated into urban planning and development designs to maintain resident bird life and overall species diversity in urban environments.
Sources
- Daigneau, Elizabeth, “Where the Birds Are”, Governing Magazine, July 2012.
- Melles, Stephanie, Susan Glenn, and Kathy Martin, “Urban Bird Diversity and Landscape Complexity: Species–environment Associations Along a Multiscale Habitat Gradient”, Conservation Ecology 7(1): 5. 2003.
- Pugh, Thomas, et. al. “Effectiveness of Green Infrastructure for Improvement of Air Quality in Urban Street Canyons”, Environmental Science and Technology, June 2012.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.