Seminar #86 from Online Seminars for Municipal Arborists
April - June 2020
Updated July 2021
Sections Go directly to the section by clicking on the title below
April - June 2020
Updated July 2021
Sections Go directly to the section by clicking on the title below
- How We Can Deal With Climate Change
- The Best Solution to Global Warming
- Tree of the Seminar #86
- Do We Know Enough to Save the Planet?
- Climate Change in a Nutshell
- Soil Specification for Urban Tree Installation
- Have Two Cities Found the Answer?
- Urban Tree of the Year 2020
- Trees With Tales - A Tree's Survival Story
- Growing Trees in a City Sidewalk
Note: Click on green text in each section for more information and photos.
Note: Click on green text in each section for more information and photos.
How We Can Deal With Climate Change
By Len Phillips
The subjects of climate change and global warming are in the news just about every day, but there never seems to be a reasonable solution. I have decided to dedicate the articles in this Seminar to discussing actions that we might take to make a little difference in our cities and improve the global future for our children.
Global warming is driving humanity toward a whole new level of worldly risks, according to a report from a United Nations scientific panel. Even though global warming began a couple centuries ago, with the industrial revolution, a panel of scientists indicated that a wild climate ride has only just begun. No one on the planet is going to escape the impacts of climate change without substantial changes from what we know today. The twenty-first century disasters such as the rising incidence of ticks and mosquito-borne diseases, widespread flu outbreaks and the coronavirus, deadly flooding in Mozambique, Thailand, and Pakistan, killer heat waves in Europe, hurricanes in the Southeastern sections of the US, droughts everywhere, and wildfires in the western half of the United States and all over Brazil and Australia, all highlight how vulnerable humanity is to extreme weather. With 70% of the global population expected to be living in cities by the year 2050, the dangers are going to worsen as the climate changes intensify. While the average global temperature has risen 0.2 degrees C since 2005, the average heat in big cities and large population centers has gone up 0.8 degrees C in the same time frame. Climate change is a scourge, sparing no one, but affecting everyone. The special toll it takes on children makes it cruel as well.
Other changes involve the price and availability of food, and to a lesser and more qualified extent, more diseases, financial costs, and even world peace is at risk. The impacts are going to be more in number and size, and sooner than the scientists had anticipated. The report predicts that the first hits would be to plants and animals, both on land and in the acidifying oceans. Climate change will worsen problems such as poverty, sickness, violence, and refugees. The increasing magnitudes of warming will increase the likelihood of severe, pervasive, and irreversible impacts on living things everywhere.
It is true that a lot of effort has been put into large reforestation projects with seedlings, but the problems are occurring in our cities where more mature trees are being removed than are being replaced. It is the cities that need help the most.
According to the U.S. Census Bureau, about 79% of the population lives on 3.1% of the total land area within the US. According to the scientists representing the US, this fact has resulted in urban heat islands building up in most large cities where temperatures are averaging several degrees warmer than the surrounding countryside. This is causing great stress on the urban forests as well as urban residents and visitors to our cities. These higher temperatures along with reduced rainfall in many regions have increased the number of diseases and pests within the urban forests. Residents of our cities are finding relief from the urban heat islands when they can see and visit urban forests. This fact has been illustrated in many research reports.
What can we do about the changing climate?
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, Utility Specialist, Tree Worker/Aerial Lift, 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 Len Phillips
The subjects of climate change and global warming are in the news just about every day, but there never seems to be a reasonable solution. I have decided to dedicate the articles in this Seminar to discussing actions that we might take to make a little difference in our cities and improve the global future for our children.
Global warming is driving humanity toward a whole new level of worldly risks, according to a report from a United Nations scientific panel. Even though global warming began a couple centuries ago, with the industrial revolution, a panel of scientists indicated that a wild climate ride has only just begun. No one on the planet is going to escape the impacts of climate change without substantial changes from what we know today. The twenty-first century disasters such as the rising incidence of ticks and mosquito-borne diseases, widespread flu outbreaks and the coronavirus, deadly flooding in Mozambique, Thailand, and Pakistan, killer heat waves in Europe, hurricanes in the Southeastern sections of the US, droughts everywhere, and wildfires in the western half of the United States and all over Brazil and Australia, all highlight how vulnerable humanity is to extreme weather. With 70% of the global population expected to be living in cities by the year 2050, the dangers are going to worsen as the climate changes intensify. While the average global temperature has risen 0.2 degrees C since 2005, the average heat in big cities and large population centers has gone up 0.8 degrees C in the same time frame. Climate change is a scourge, sparing no one, but affecting everyone. The special toll it takes on children makes it cruel as well.
Other changes involve the price and availability of food, and to a lesser and more qualified extent, more diseases, financial costs, and even world peace is at risk. The impacts are going to be more in number and size, and sooner than the scientists had anticipated. The report predicts that the first hits would be to plants and animals, both on land and in the acidifying oceans. Climate change will worsen problems such as poverty, sickness, violence, and refugees. The increasing magnitudes of warming will increase the likelihood of severe, pervasive, and irreversible impacts on living things everywhere.
It is true that a lot of effort has been put into large reforestation projects with seedlings, but the problems are occurring in our cities where more mature trees are being removed than are being replaced. It is the cities that need help the most.
According to the U.S. Census Bureau, about 79% of the population lives on 3.1% of the total land area within the US. According to the scientists representing the US, this fact has resulted in urban heat islands building up in most large cities where temperatures are averaging several degrees warmer than the surrounding countryside. This is causing great stress on the urban forests as well as urban residents and visitors to our cities. These higher temperatures along with reduced rainfall in many regions have increased the number of diseases and pests within the urban forests. Residents of our cities are finding relief from the urban heat islands when they can see and visit urban forests. This fact has been illustrated in many research reports.
What can we do about the changing climate?
- We must begin by informing as many people as we can about the benefits of healthy trees, shrubs, and plantings in the urban environment. We must also relay this message to public officials. Although about half of our cities have begun adapting to climate change with programs to reduce energy consumption, conserve water, and improve landscapes, more needs to be done. For example, very few people are looking at the urban canopy or how landscapes might affect the overall natural climatic balance. Tree planting programs are underfunded just about everywhere. Most political leaders do not know that arborists have the technical knowledge and experience to provide invaluable assistance in areas such as proper management of herbicides, water conservation and planting designs. Efforts in these areas might be of more benefit than solar panels on the roof.
- More city planners and consultants need to be aware of the positive effects of how adding green planting and maintaining our urban canopy properly would make a substantial difference in lowering the heat, increase oxygen in the atmosphere, and help sustain a healthier urban environment. For example, very little thought is given to making our traffic islands and parking lots greener and cooler with more trees.
- On a very hot day during the first heat wave of this coming summer, call the local press to show the reporters how people can deal with the hot temperatures. Show them two large thermometers, one in the shade and one a few feet away in the full sun. This effort will surely result in public pressure to fund the installation of more public trees and encourage city residents to install more trees on their own property if they have the space. You might also use the example to promote proper tree installation and management.
- As arborists and landscape architects, let us try to plant as many trees as we can afford. I recommend planting bare root trees because you can plant twice as many BR trees as the cost of the B&B trees in your budget. If possible, be sure the trees have fibrous root systems that will tolerate the urban soils. I also recommend you gather volunteers to help you plant these light-weight BR trees. Without a contractor doing the planting, you can plant even more bare root trees. Re-read the articles found in the Topic “All About Bare Root Trees”, especially the section pertaining to a “Tree Planting Program that Works”. During the installation process, follow the directions mentioned in “Tips for Planting Bare Root Trees” in this same Topic.
- Consider adding a shovel full of rich loam from around the roots of a nearby established tree of the same genus to add some beneficial mycorrhizal fungi that will help a new tree being installed, so it will thrive in future years, or sprinkle some fungal inoculants over the bare roots.
- Grow the right tree, in the right place, for the right purpose. (Article found in Topic #9)
- Be sure you are doing your part to conserve energy and water. To reduce burning fossil fuels, turn off your engine when the truck is not in use. Are your trips to and from the job sites, taking the shortest routes? Do you have all the tools you need to do the job, so you do not have to run back to the garage for something else? Do you combine your errands into one trip instead of many? If you have not yet replaced your gas powered chainsaws with battery pack models, they are available from your local chainsaw dealers. Are you using vegetable oil to replace the bar oil in your chain saw?
- This list could go on and on. Let me know if you have other ideas to save energy and cool our cities down. Send your ideas to me at lenphillips@yahoo.com and you may be published in the next Online Seminar.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, Utility Specialist, Tree Worker/Aerial Lift, 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.
The Best Solution to Global Warming
Edited By Len Phillips
“Big shade trees deserve a high five for cooling our cities while delivering a suite of environmental and health benefits. A handful of reasons to plant trees begins with the most obvious. Big shade trees:
1. reduce energy costs via direct shading of buildings and pavement and reducing temperatures via evapotranspiration,
2. help to manage stormwater onsite and reduce runoff,
3. convert carbon dioxide to oxygen and scrub the air of harmful particulates,
4. provide essential health benefits, and
5. increase property values.” J. Frank Schmidt
Besides big shade trees, the next best way human beings can help reverse global warming is to plant more trees. Better still, plant trees that will be tolerant of the rising temperatures, so they will survive when other trees may not. The heat tolerance is based on a general comparison to other trees. For example, Cinnamon Girl paperbark maple is more heat tolerant compared to other paperbark maples, but not when compared to a species like Japanese maples.
As you can see on the list below, there are many species of trees that will tolerate heat as far south as to the Hardiness Zone 9 of southern Florida, but there are also many new introductions that have been selected for their heat tolerance in addition to other desirable features. The more heat tolerant cultivars are indicated on the “Cultivars” column below. If no cultivars are listed, it means that all available cultivars of that species are tolerant of heat.
Keep in mind that although these trees are heat tolerant, that does not mean that they are also resistant to drought, disease, pest problems or other abiotic conditions. For example, do not plant Fraxinus if the emerald ash borer is coming your way. In other words, when you are selecting a tree for planting, make sure you plant the right tree in the right spot, for the right reason.
Heat Tolerant Trees
Botanical Name Trade Name Cultivars
Abies firdma Japanese momi fir
Acer campestre Hedge maple
Acer ginnala Amur maple Red November 'JFS-UGA'
A. griseum x A. nikoense Paperbark maple Cinnamon Girl 'Molly Fordham'
Acer miyabei Miyabe maple State Street™'Morton', Rugged Ridge® 'JFS-KW3AMI'
Acer negundo Boxelder 'Sensation', 'Variegatum'
Acer pseudoplatanus Sycamore maple
Acer rubrum Red maple October Glory 'PNI 0268', Autumn Fantasy 'DTR 102', Autumn Flame, Brandywine, Redpointe 'Frank Jr', Summer Red 'HOSR'
Acer saccharum Sugar maple Autumn Faith 'Hawkersmith 1', Autumn Splendor, Legacy®, Commemoration, Belle Tower 'Reba', Fall Fiesta® 'Bailsta, Flashfire 'JFS-Caddo 2', Green Mountain®, John Pair,
Steeple 'Astis', Powder Keg 'WhitXLIX',
Acer x freemanii Freeman maple Armstrong, Autumn Blaze® 'Jeffersred'
Acer saccharinum Silver maple
Acer tataricum Tataricum maple Beethoven 'Betzam'
Acer truncatum Purpleblow maple Norwegian Sunset 'Keithsform', Pacific Sunset 'Warrenred'
Crimson Sunset ‘JFS-KW202’, Fire Dragon,
Urban Sunset 'JFS-KW187' Ruby Sunset 'JFS-KW249'
Aesculus hippocastanum Horsechestnut
Ailanthus altissima Chinese sumac
Betula nigra River birch City Slicker 'WhitXXV', DuraHeat®'BNMTF', Heritage® ‘Cully’
Carpinus betulus Hornbeam Emerald Avenue® 'JFS-KW1CB' PP 22814
Carpinus caroliniana Ironwood Native Flame 'JFS-KW6'
Catalpa speciosa Northern catalpa Heartland®'Hiawatha 2'
Cedrus atlantica Atlas cedar
Celtis occidentalis Common hackberry Prairie Sentinel®‘JFS-KSU1’, Magnifica'
Chionanthus virginicus White fringetree Dirr Clone
Cladrastis kentukea Yellowwood Perkins Pink (Rosea)
Cornus florida Flowering dogwood Cherokee Princess
Cornus kousa Kousa dogwood Scarlet Fire 'Rutpink'
Cornus x elwinortonii Rutgers hybrid dogwood Venus 'KN30-8', Starlight 'KN4-43', Rosy Teacups 'KN144-2'
Crataegus laevigata English hawthorn
Crataegus x lavalleei Lavalle hawthorn Carrierei
Crataegus viridis Green hawthorn Winter King
Cupressus arizonica Arizona cypress Carolina Sapphire
Cupressus x leylandii Leyland cypress Naylor's Blue
Cupressus x notabilis Alice Holt cypress
Fagus grandifloia American beech
Fraxinus pennsylvanica Green ash * Cimmaron™'Cimmzam', Urbanite™ 'Urbdell'
Ginkgo biloba Ginkgo all male cultivars
Gleditsia triacanthos var. inermis Thornless Honeylocust all male cultivars
Gymnocladus dioicus Kentucky Coffeetree Espresso™‘Espresso-JFS’
Ilex 'Nellie R. Stevens' Nellie R. Stevens holly
Ilex opaca American holly
Juniperus chinensis Chinese juniper Hetzii Columnaris, Keteleeri
Juniperus virginiana Eastern redcedar most cultivars
Koelreuteria paniculata Goldenrain tree Fastigiata, Summerburst, JFS 'Sunleaf'
Lagerstroemia Crapemyrtle
Liquidambar styraciflua American sweetgum Emerald Sentinel® ‘Clydesform’, ’Palo Alto’
Liriodendron tulipifera Tuliptree Emerald City®‘JFS-Oz‘
Maclura pomifera Osage orange ‘Wichita’, ‘White Shield’
Magnolia x soulangeana Saucer magnolia most cultivars
Magnolia stellata Star magnolia Centennial Blush, Royal Star
Magnolia tripetala Umbrella magnolia Ginter Spicy White
Magnolia virginiana Sweetbay magnolia Keltyk 'MVMTF'
Malus spp. Flowering crabapple 'Adams','Brandywine ''Branzam', Royal Raindrops, M. sargentii
Melia azedarach Chinaberry
Morus alba Mulberry
Nyssa sylvatica Black gum new cultivars
Ostrya virginiana American hophornbeam Autumn Treasure®‘JFS-KW5’
Oxydendrum araboreum Sourwood
Parrotia persica Persian parrotia Ruby Vase ’Inge', Persian Spire™‘JLColumnar’,‘Vanessa’
Parrotia subaequalis Chinese parrotia
Paulownia tomentosa Empress tree
Pinus ayacahuite Mexican white pine
Pinus canariensis Canary Island pine
Pinus halepensis Aleppo pine
Pinus palustris Longleaf pine
Pinus taeda Loblolly pine
Pinus thunbergii Japanese black pine
Pistacia chinensis Chinese pistache
Platanus x acerifolia London planetree ‘Columbia’
Platanus occidentalis Sycamore
Platycladus orientalis Oriental arborvitae
Prunus campanulata Formosan cherry 'Abigail Adams', 'Okame'
Prunus species almond, apricot, cherry, peach, and plum
Pseudocydonia sinensis Chinese quince
Pseudolarix amabilis Golden larch
Quercus bicolor Swamp white oak 'American Dream 'JFS-KW12', Beacon 'Bonnie and Mike'
Quercus coccinea Scarlet oak
Quercus hemisphaerica Laurel oak
Quercus lyrata Overcup oak Highbeam 'QLFTB', Marquee 'Hopeulikit'
Quercus macrocarpa Bur oak
Quercus nigra Water oak
Quercus nuttallii Nuttall oak Esplanade 'QNSTC', Highpoint 'QNFTA'
Quercus phellos Willow oak Hightower 'QPSTA'
Quercus shumardii Shumard oak Madison 'ACNRT1', Panache 'QSFTC', Prominence 'QSSTH'
Quercus stellata Post oak
Robinia pseudoacacia Black locust ** Bessoniana, Chicago Blues 'Benjamin', Frista,
Twisty Baby 'Lace Lady'
Sassafras albidum Common sassafras ‘Birch Mountain’
Sorbus aucuparia European mountain ash
Sorbus intermedia Swedish whitebeam
Styrax japonicus Japanese snowbell Emerald Pagoda 'Sohuksan',Marley's Pink 'JL Weeping'
Prystine Spire 'MTFSJ', Spring Showers
Syringa pekinensis Peking lilac China Snow 'Morton', Summer Charm 'DTR 124'
Taxodium distichum Baldcypress Shawnee Brave®‘Michelson’
Tilia americana American Linden ‘Redmond’
Tilia tomentosa Silver Linden ‘Sterling’,Green Mountain®‘PNI 6051’,
Satin Shadow™‘Sashazam’
Ulmus americana American Elm ‘New Harmony’, Jefferson’, ‘Valley Forge’, 'Princeton’ ***
Ulmus parvifolia Lacebark Elm Allee®‘Emer II’, Drake,‘Small Frye’
Ulmus propinqua Chalkbark Elm Emerald Sunshine® ‘JFS-Bieberich’
Ulmus pumila Siberian Elm
Viburnum prunifolium Blackhaw viburnum
Viburnum rufidulum Rusty blackhaw viburnum
Vitex agnus-castus Chastetree Abbeville Blue, Le Compte, Mississippi Blues
Zelkova serrata Japanese Zelkova Green Vase®, ‘Musashino’, Village Green, Wireless
Cautionary Notes
* When considering ash, use caution regarding the potentially lethal emerald ash borer.
** Avoid black locust species due to sucker growth; the cultivars and hybrids are less prone to suckers.
*** Princeton elms should be cuttings and not seedlings from the original Princeton elm to have resistance to Dutch elm disease.
I hope you find this list useful. Plant wisely and keep the future in mind.
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, Tree Worker/Climber, Tree Worker/Aerial Lift, or 0.25 CEUs toward BCMA science and 0.25 CEUs toward 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
“Big shade trees deserve a high five for cooling our cities while delivering a suite of environmental and health benefits. A handful of reasons to plant trees begins with the most obvious. Big shade trees:
1. reduce energy costs via direct shading of buildings and pavement and reducing temperatures via evapotranspiration,
2. help to manage stormwater onsite and reduce runoff,
3. convert carbon dioxide to oxygen and scrub the air of harmful particulates,
4. provide essential health benefits, and
5. increase property values.” J. Frank Schmidt
Besides big shade trees, the next best way human beings can help reverse global warming is to plant more trees. Better still, plant trees that will be tolerant of the rising temperatures, so they will survive when other trees may not. The heat tolerance is based on a general comparison to other trees. For example, Cinnamon Girl paperbark maple is more heat tolerant compared to other paperbark maples, but not when compared to a species like Japanese maples.
As you can see on the list below, there are many species of trees that will tolerate heat as far south as to the Hardiness Zone 9 of southern Florida, but there are also many new introductions that have been selected for their heat tolerance in addition to other desirable features. The more heat tolerant cultivars are indicated on the “Cultivars” column below. If no cultivars are listed, it means that all available cultivars of that species are tolerant of heat.
Keep in mind that although these trees are heat tolerant, that does not mean that they are also resistant to drought, disease, pest problems or other abiotic conditions. For example, do not plant Fraxinus if the emerald ash borer is coming your way. In other words, when you are selecting a tree for planting, make sure you plant the right tree in the right spot, for the right reason.
Heat Tolerant Trees
Botanical Name Trade Name Cultivars
Abies firdma Japanese momi fir
Acer campestre Hedge maple
Acer ginnala Amur maple Red November 'JFS-UGA'
A. griseum x A. nikoense Paperbark maple Cinnamon Girl 'Molly Fordham'
Acer miyabei Miyabe maple State Street™'Morton', Rugged Ridge® 'JFS-KW3AMI'
Acer negundo Boxelder 'Sensation', 'Variegatum'
Acer pseudoplatanus Sycamore maple
Acer rubrum Red maple October Glory 'PNI 0268', Autumn Fantasy 'DTR 102', Autumn Flame, Brandywine, Redpointe 'Frank Jr', Summer Red 'HOSR'
Acer saccharum Sugar maple Autumn Faith 'Hawkersmith 1', Autumn Splendor, Legacy®, Commemoration, Belle Tower 'Reba', Fall Fiesta® 'Bailsta, Flashfire 'JFS-Caddo 2', Green Mountain®, John Pair,
Steeple 'Astis', Powder Keg 'WhitXLIX',
Acer x freemanii Freeman maple Armstrong, Autumn Blaze® 'Jeffersred'
Acer saccharinum Silver maple
Acer tataricum Tataricum maple Beethoven 'Betzam'
Acer truncatum Purpleblow maple Norwegian Sunset 'Keithsform', Pacific Sunset 'Warrenred'
Crimson Sunset ‘JFS-KW202’, Fire Dragon,
Urban Sunset 'JFS-KW187' Ruby Sunset 'JFS-KW249'
Aesculus hippocastanum Horsechestnut
Ailanthus altissima Chinese sumac
Betula nigra River birch City Slicker 'WhitXXV', DuraHeat®'BNMTF', Heritage® ‘Cully’
Carpinus betulus Hornbeam Emerald Avenue® 'JFS-KW1CB' PP 22814
Carpinus caroliniana Ironwood Native Flame 'JFS-KW6'
Catalpa speciosa Northern catalpa Heartland®'Hiawatha 2'
Cedrus atlantica Atlas cedar
Celtis occidentalis Common hackberry Prairie Sentinel®‘JFS-KSU1’, Magnifica'
Chionanthus virginicus White fringetree Dirr Clone
Cladrastis kentukea Yellowwood Perkins Pink (Rosea)
Cornus florida Flowering dogwood Cherokee Princess
Cornus kousa Kousa dogwood Scarlet Fire 'Rutpink'
Cornus x elwinortonii Rutgers hybrid dogwood Venus 'KN30-8', Starlight 'KN4-43', Rosy Teacups 'KN144-2'
Crataegus laevigata English hawthorn
Crataegus x lavalleei Lavalle hawthorn Carrierei
Crataegus viridis Green hawthorn Winter King
Cupressus arizonica Arizona cypress Carolina Sapphire
Cupressus x leylandii Leyland cypress Naylor's Blue
Cupressus x notabilis Alice Holt cypress
Fagus grandifloia American beech
Fraxinus pennsylvanica Green ash * Cimmaron™'Cimmzam', Urbanite™ 'Urbdell'
Ginkgo biloba Ginkgo all male cultivars
Gleditsia triacanthos var. inermis Thornless Honeylocust all male cultivars
Gymnocladus dioicus Kentucky Coffeetree Espresso™‘Espresso-JFS’
Ilex 'Nellie R. Stevens' Nellie R. Stevens holly
Ilex opaca American holly
Juniperus chinensis Chinese juniper Hetzii Columnaris, Keteleeri
Juniperus virginiana Eastern redcedar most cultivars
Koelreuteria paniculata Goldenrain tree Fastigiata, Summerburst, JFS 'Sunleaf'
Lagerstroemia Crapemyrtle
Liquidambar styraciflua American sweetgum Emerald Sentinel® ‘Clydesform’, ’Palo Alto’
Liriodendron tulipifera Tuliptree Emerald City®‘JFS-Oz‘
Maclura pomifera Osage orange ‘Wichita’, ‘White Shield’
Magnolia x soulangeana Saucer magnolia most cultivars
Magnolia stellata Star magnolia Centennial Blush, Royal Star
Magnolia tripetala Umbrella magnolia Ginter Spicy White
Magnolia virginiana Sweetbay magnolia Keltyk 'MVMTF'
Malus spp. Flowering crabapple 'Adams','Brandywine ''Branzam', Royal Raindrops, M. sargentii
Melia azedarach Chinaberry
Morus alba Mulberry
Nyssa sylvatica Black gum new cultivars
Ostrya virginiana American hophornbeam Autumn Treasure®‘JFS-KW5’
Oxydendrum araboreum Sourwood
Parrotia persica Persian parrotia Ruby Vase ’Inge', Persian Spire™‘JLColumnar’,‘Vanessa’
Parrotia subaequalis Chinese parrotia
Paulownia tomentosa Empress tree
Pinus ayacahuite Mexican white pine
Pinus canariensis Canary Island pine
Pinus halepensis Aleppo pine
Pinus palustris Longleaf pine
Pinus taeda Loblolly pine
Pinus thunbergii Japanese black pine
Pistacia chinensis Chinese pistache
Platanus x acerifolia London planetree ‘Columbia’
Platanus occidentalis Sycamore
Platycladus orientalis Oriental arborvitae
Prunus campanulata Formosan cherry 'Abigail Adams', 'Okame'
Prunus species almond, apricot, cherry, peach, and plum
Pseudocydonia sinensis Chinese quince
Pseudolarix amabilis Golden larch
Quercus bicolor Swamp white oak 'American Dream 'JFS-KW12', Beacon 'Bonnie and Mike'
Quercus coccinea Scarlet oak
Quercus hemisphaerica Laurel oak
Quercus lyrata Overcup oak Highbeam 'QLFTB', Marquee 'Hopeulikit'
Quercus macrocarpa Bur oak
Quercus nigra Water oak
Quercus nuttallii Nuttall oak Esplanade 'QNSTC', Highpoint 'QNFTA'
Quercus phellos Willow oak Hightower 'QPSTA'
Quercus shumardii Shumard oak Madison 'ACNRT1', Panache 'QSFTC', Prominence 'QSSTH'
Quercus stellata Post oak
Robinia pseudoacacia Black locust ** Bessoniana, Chicago Blues 'Benjamin', Frista,
Twisty Baby 'Lace Lady'
Sassafras albidum Common sassafras ‘Birch Mountain’
Sorbus aucuparia European mountain ash
Sorbus intermedia Swedish whitebeam
Styrax japonicus Japanese snowbell Emerald Pagoda 'Sohuksan',Marley's Pink 'JL Weeping'
Prystine Spire 'MTFSJ', Spring Showers
Syringa pekinensis Peking lilac China Snow 'Morton', Summer Charm 'DTR 124'
Taxodium distichum Baldcypress Shawnee Brave®‘Michelson’
Tilia americana American Linden ‘Redmond’
Tilia tomentosa Silver Linden ‘Sterling’,Green Mountain®‘PNI 6051’,
Satin Shadow™‘Sashazam’
Ulmus americana American Elm ‘New Harmony’, Jefferson’, ‘Valley Forge’, 'Princeton’ ***
Ulmus parvifolia Lacebark Elm Allee®‘Emer II’, Drake,‘Small Frye’
Ulmus propinqua Chalkbark Elm Emerald Sunshine® ‘JFS-Bieberich’
Ulmus pumila Siberian Elm
Viburnum prunifolium Blackhaw viburnum
Viburnum rufidulum Rusty blackhaw viburnum
Vitex agnus-castus Chastetree Abbeville Blue, Le Compte, Mississippi Blues
Zelkova serrata Japanese Zelkova Green Vase®, ‘Musashino’, Village Green, Wireless
Cautionary Notes
* When considering ash, use caution regarding the potentially lethal emerald ash borer.
** Avoid black locust species due to sucker growth; the cultivars and hybrids are less prone to suckers.
*** Princeton elms should be cuttings and not seedlings from the original Princeton elm to have resistance to Dutch elm disease.
I hope you find this list useful. Plant wisely and keep the future in mind.
Sources
- Special thanks to Keith Warren, Richard Harper, Mandy Bayer, and Ashley McElhinney for their careful review of this list. 2019
- Appleton, Bonnie, et. al. “Trees for hot sites”, Virginia Cooperative Extension, Publication 430-024, 2015
- Dirr, Michael A. and Keith S. Warren, “The Tree Book”, Timber Press, 2019.
- J Frank Schmidt Reference Guide, 2018.
- Massachusetts Department of Environmental Conservation and the Center for Agriculture Food and the Environment at the University of Massachusetts for compiling a list of trees that will tolerate tough urban environments. For more information click on the ‘Lectures’ section at complete guide.
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, Tree Worker/Climber, Tree Worker/Aerial Lift, or 0.25 CEUs toward BCMA science and 0.25 CEUs toward 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.
Urban Tree of the Seminar
By Len Phillips
Flashfire® Maple is a selection developed for heat and drought resistance. It is a tree that has been selected for its tolerance to global warming. It has better leaf tatter and mildew resistance than other Caddo selections, strong growth, and brilliant red, early autumn color.
Common Name: Flashfire® Maple
Botanical Name: Acer saccharum 'JFS-Caddo2'
Parentage: A selection from the western Oklahoma, Caddo source of trees
Hardiness Zone: 4b – 9
Height: 45'
Spread: 40'
Plant Patent: # 23361’
Form: Oval in youth and broadly oval with age
Bloom Period: May
Flower: Greenish yellow and insignificant
Fruit: It produces very few seeds
Foliage: Dark green leaves are glossy as well as heat and tatter-resistant
Autumn Foliage: Bright fire engine red in autumn
Winter Interest: Brown young bark provides winter interest
Bark: Typically maple and turns gray brown with age
Growth Rate: Moderate, less than 1 ft. a year, 45' tall in 30 years
Planting: Easy to transplant
Propagating: Stem cuttings, budded or grafted
Site Requirements: Excellent heat and drought tolerance
Pest Problems: None
Salt Tolerance: Good
Design Uses: Excellent specimen for lawn, park, street, and residential use
Companions: Use with evergreen shrubs planted the year after planting the tree
Other Comments: Calipers well and develops a uniformly branched canopy with minimal pruning.
Ideal tree for city streets.
Photo
Source: Dirr, Michael A. and Keith S. Warren, “The Tree Book”, Timber Press, 201
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, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Len Phillips
Flashfire® Maple is a selection developed for heat and drought resistance. It is a tree that has been selected for its tolerance to global warming. It has better leaf tatter and mildew resistance than other Caddo selections, strong growth, and brilliant red, early autumn color.
Common Name: Flashfire® Maple
Botanical Name: Acer saccharum 'JFS-Caddo2'
Parentage: A selection from the western Oklahoma, Caddo source of trees
Hardiness Zone: 4b – 9
Height: 45'
Spread: 40'
Plant Patent: # 23361’
Form: Oval in youth and broadly oval with age
Bloom Period: May
Flower: Greenish yellow and insignificant
Fruit: It produces very few seeds
Foliage: Dark green leaves are glossy as well as heat and tatter-resistant
Autumn Foliage: Bright fire engine red in autumn
Winter Interest: Brown young bark provides winter interest
Bark: Typically maple and turns gray brown with age
Growth Rate: Moderate, less than 1 ft. a year, 45' tall in 30 years
Planting: Easy to transplant
Propagating: Stem cuttings, budded or grafted
Site Requirements: Excellent heat and drought tolerance
Pest Problems: None
Salt Tolerance: Good
Design Uses: Excellent specimen for lawn, park, street, and residential use
Companions: Use with evergreen shrubs planted the year after planting the tree
Other Comments: Calipers well and develops a uniformly branched canopy with minimal pruning.
Ideal tree for city streets.
Photo
Source: Dirr, Michael A. and Keith S. Warren, “The Tree Book”, Timber Press, 201
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, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Do We Know Enough to Save the Planet?
Edited by Len Philips
The answer is...
not yet, because we really need to do more. Too many cities are falling short on tree plantings every year because the budget to plant trees is considered a low priority. Trees around the world are being cut down, burned up, or dying, and there are few or no funds to replace them. Forests have been fragmented into tiny slivers because we wanted the lumber and paper products that trees provide, and we do not have enough regard for reforestation. Both air pollution and soil abuse caused by mankind have also taken a toll on trees in our cities and suburbs. It's not only the changes brought by a warmer planet, it is also because since the start of the industrial revolution we have treated the world's trees poorly and without regard to the ecological consequences.
What we do know!
We do know that trees are the planet's heat shield because they cool the temperature in the shade of a tree by 18°F (10°C). Tree leaves also filter our air and soak up climate-warming carbon dioxide, while tree roots filter our water and slow runoff during rainfall. Many of the world's damaging floods are becoming more frequent and more powerful and too often they are caused by deforestation upstream. Many other floods are caused by super storms at sea that blow ashore. Super storms are, in part, the result of global warming.
Many different kinds of chemicals are emitted by trees and forests that are beneficial to mankind. Many tree compounds have been proven to be antibacterial, anti-fungal, anti-viral and even cancer prevention compounds. One of the most well-known is Taxol from the Pacific yew tree (Taxus brevifolia), which is a powerful cancer fighting drug. Another example is the active ingredient of aspirin, acetylsalicylic acid which comes from the bark of willow trees (Salix alba).
Humans have lived in harmony with nature for thousands of years. Through evolution, we were made to fit into a natural environment, so we feel stress when we are placed in an urban environment. Hiking through the forest has been shown to reduce stress-causing chemicals in the human body and increase natural killer cells in the human immune system that fight tumors and viruses. Researchers have demonstrated that anxiety, depression, and even crimes occur less frequently in neighborhoods with trees.
Trees are also used in many places to prevent soil erosion and shade certain crops. Trees can be used to clean up toxic waste sites containing explosives, solvents, and organic wastes, by using a process known as phytoremediation.
What we do not know!
Scientists admit that trees, forests, and soils are poorly studied. We do not know why trees are greatly underused as an eco-technology to make natural systems, as well as the world's cities, more resilient. More work is needed to improve watershed management. Phytoremediation, mentioned above, works but has a long way to go before it is accepted by all people as an acceptable way of dealing with pollutants.
Still uncertain is the question of what to plant to withstand the challenges of a changing climate in order to assure survival of the trees that we do plant. On a local level many arborists have a difficult time deciding what is the right tree for the right place and what is the right reason. If arborists have a tough time with this, how are the typical landowners able to make these decisions correctly?
To help trees deal with the changing climate, many nurseries are actively breeding trees that are pest resistant and tolerant of urban sites. Other nurseries actively select the best trees, or the longest living trees, or trees that have other highly desirable features and breeding these trees to survive into the next century. But it is still not enough and much more work and study needs to continue. We need trees that can soak up carbon and store it in the soil. Arborists must start using these climate adaptable trees. (See “The Best Solution to Global Warming”, the second article in this Seminar.)
Many forests across the entire range of the Rocky Mountains have thinned out, burned up, or died in the last decade. Most of the mature forests of British Columbia are gone due to a combination of warming climate and the increased presence of new insect pests, and we do not know how to stop the process as the devastation continues creeping across the land.
The bristlecone pines (Pinus aristata) in the U.S. are the most ancient trees in the world, with some more than 5,000 years old. But they will be dead in the next few years because of a combination of bark beetles and a fungal disease, enabled by the warmer climate. Tree-ring studies on the bristlecone show that the last 50 years are the warmest half century in the last 3,700 years.
What we need to do!
A marine chemist in Japan has discovered that as the leaves from trees decompose, the humic acid leaches into the ocean and helps fertilize plankton, a critical food for many other forms of sea life. Japanese fisherman began an award-winning campaign called Forests Are the Lovers of the Sea, and have been planting trees along the coasts and rivers to rejuvenate fish and oyster populations. In the Gulf of Mexico region, a nursery called Acorns of Hope has donated 10,000 live oak trees from its nursery, so far. They will be continuing this effort of planting live oaks along the Gulf coast shoreline, as far into the future as they can. So far they have planted trees along one river flowing into the Gulf. This is the only example of ocean shoreline planting in the US that I have heard about. If you know of any, please send me an email.
We need to recognize that trees can communicate among themselves, which greatly helps them survive diseases and pests. However, mankind has not yet learned their language, but learning it may well be a key to their survival.
It is time to act. We have all heard the expression, “When is the best time to plant a tree? Twenty years ago! When is the second-best time? Today!” It is time for you to do your best to plant as many trees as you can.
Source
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, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or 0.25 CEUs toward BCMA science and 0.25 CEUs toward 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 Philips
The answer is...
not yet, because we really need to do more. Too many cities are falling short on tree plantings every year because the budget to plant trees is considered a low priority. Trees around the world are being cut down, burned up, or dying, and there are few or no funds to replace them. Forests have been fragmented into tiny slivers because we wanted the lumber and paper products that trees provide, and we do not have enough regard for reforestation. Both air pollution and soil abuse caused by mankind have also taken a toll on trees in our cities and suburbs. It's not only the changes brought by a warmer planet, it is also because since the start of the industrial revolution we have treated the world's trees poorly and without regard to the ecological consequences.
What we do know!
We do know that trees are the planet's heat shield because they cool the temperature in the shade of a tree by 18°F (10°C). Tree leaves also filter our air and soak up climate-warming carbon dioxide, while tree roots filter our water and slow runoff during rainfall. Many of the world's damaging floods are becoming more frequent and more powerful and too often they are caused by deforestation upstream. Many other floods are caused by super storms at sea that blow ashore. Super storms are, in part, the result of global warming.
Many different kinds of chemicals are emitted by trees and forests that are beneficial to mankind. Many tree compounds have been proven to be antibacterial, anti-fungal, anti-viral and even cancer prevention compounds. One of the most well-known is Taxol from the Pacific yew tree (Taxus brevifolia), which is a powerful cancer fighting drug. Another example is the active ingredient of aspirin, acetylsalicylic acid which comes from the bark of willow trees (Salix alba).
Humans have lived in harmony with nature for thousands of years. Through evolution, we were made to fit into a natural environment, so we feel stress when we are placed in an urban environment. Hiking through the forest has been shown to reduce stress-causing chemicals in the human body and increase natural killer cells in the human immune system that fight tumors and viruses. Researchers have demonstrated that anxiety, depression, and even crimes occur less frequently in neighborhoods with trees.
Trees are also used in many places to prevent soil erosion and shade certain crops. Trees can be used to clean up toxic waste sites containing explosives, solvents, and organic wastes, by using a process known as phytoremediation.
What we do not know!
Scientists admit that trees, forests, and soils are poorly studied. We do not know why trees are greatly underused as an eco-technology to make natural systems, as well as the world's cities, more resilient. More work is needed to improve watershed management. Phytoremediation, mentioned above, works but has a long way to go before it is accepted by all people as an acceptable way of dealing with pollutants.
Still uncertain is the question of what to plant to withstand the challenges of a changing climate in order to assure survival of the trees that we do plant. On a local level many arborists have a difficult time deciding what is the right tree for the right place and what is the right reason. If arborists have a tough time with this, how are the typical landowners able to make these decisions correctly?
To help trees deal with the changing climate, many nurseries are actively breeding trees that are pest resistant and tolerant of urban sites. Other nurseries actively select the best trees, or the longest living trees, or trees that have other highly desirable features and breeding these trees to survive into the next century. But it is still not enough and much more work and study needs to continue. We need trees that can soak up carbon and store it in the soil. Arborists must start using these climate adaptable trees. (See “The Best Solution to Global Warming”, the second article in this Seminar.)
Many forests across the entire range of the Rocky Mountains have thinned out, burned up, or died in the last decade. Most of the mature forests of British Columbia are gone due to a combination of warming climate and the increased presence of new insect pests, and we do not know how to stop the process as the devastation continues creeping across the land.
The bristlecone pines (Pinus aristata) in the U.S. are the most ancient trees in the world, with some more than 5,000 years old. But they will be dead in the next few years because of a combination of bark beetles and a fungal disease, enabled by the warmer climate. Tree-ring studies on the bristlecone show that the last 50 years are the warmest half century in the last 3,700 years.
What we need to do!
A marine chemist in Japan has discovered that as the leaves from trees decompose, the humic acid leaches into the ocean and helps fertilize plankton, a critical food for many other forms of sea life. Japanese fisherman began an award-winning campaign called Forests Are the Lovers of the Sea, and have been planting trees along the coasts and rivers to rejuvenate fish and oyster populations. In the Gulf of Mexico region, a nursery called Acorns of Hope has donated 10,000 live oak trees from its nursery, so far. They will be continuing this effort of planting live oaks along the Gulf coast shoreline, as far into the future as they can. So far they have planted trees along one river flowing into the Gulf. This is the only example of ocean shoreline planting in the US that I have heard about. If you know of any, please send me an email.
We need to recognize that trees can communicate among themselves, which greatly helps them survive diseases and pests. However, mankind has not yet learned their language, but learning it may well be a key to their survival.
It is time to act. We have all heard the expression, “When is the best time to plant a tree? Twenty years ago! When is the second-best time? Today!” It is time for you to do your best to plant as many trees as you can.
Source
- Robbins, Jim, “Trees, our life savers are dying”, The Guardian, July 2013
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or 0.25 CEUs toward BCMA science and 0.25 CEUs toward 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.
The Urban Forest and Climate Change in a Nutshell
by Dick Miller, Urban Forester - City of Canal Winchester, Ohio
The height of Hawaii’s Mauna Kea from the ocean floor base to the peak at 33,500 feet makes this the world’s tallest mountain from its base to the peak (Mt. Everest reaches the highest elevation). This mass of former molten lava represents a record of the existence of all life on earth. Is it possible to alter the land and air that supports all life from ocean bottom to mountain top of this planet? Can the seven billion (still growing) humans afford to enter uncharted territory as the atmospheric levels of greenhouse gases continue to rise?
Global warming is having an unquestionable impact on forest eco-systems everywhere. The climatic ramifications could be staggering for almost all eco-systems on the planet and one segment of those systems is the urban forest. The future of important urban forest functions includes their effect on stormwater, wildlife management decisions, carbon storage, energy conservation, air quality, continuing an aesthetic sense of place and most importantly the effect that the shaded forest cover will have on the over-all health of this planet. To break it down even further, all forest systems will experience over a relatively short period of time, unknown biological thresholds not experienced in their evolutionary development.
Ecological indicators of change and shifts in species distribution are not new to forest science in the Americas. The decline of quaking aspen (Populus tremuloides), possibly due to effects of climate change in the western U.S., has made news for years. Digging through an outdated Harlow and Harrar 1969 “Textbook of Dendrology”, shows the original range map of P. tremuloides in central/southern Ohio. I can no longer locate the species in that area and native stands apparently are disappearing from northern reaches of the state as well. Also noted by Harlow and Harrar, Ilex opaca (American Holly) in the 200 years prior to the middle of the 20th century, was considered a southern tree. Soon after the beginning of the automobile revolution the species marched steadily northward. The ‘natural shift’ of this plant species toward the north could be due to the warming phenomena in combination with bird species (e.g. northern mockingbird), also simultaneously moving northward that would aid in Ilex seed dissemination.
The primary reason for forest canopy decline where insect and disease are presently moving through forest stands, may be directly related to warming. Simply put, insects and disease are secondary or even tertiary in response to other changes in the forest. Jim Chatfield, associate professor at the Ohio State University notes in 2012 “that the bagworm moth (Thyridoptery x ephemeraeformis) has altered its range due to mild winters in Ohio. Prior to 1980, the insect was rarely able to survive north of the central regions of the state. Now the insect can survive the winters of Michigan.” How a species arrives in a new eco-region by migration or some form of un-natural shift, (e.g. hidden in a wooden shipping pallet of another continental origin), may be inconsequential relative to future survival of the organism. In addition, the native southern pine beetle in the east and native mountain pine beetle in the west are expanding their ranges laterally as well as to higher elevations. All forest types including the urban monocultures are on the brink of succumbing to insects and disease with primary foundations in minute changes in the overall climate.
Urban foresters and others, while not dealing with forest ecosystems that are totally natural, are no less responsible to ensure a viable forest canopy where the most important attribute (relative to the future urban heat island effect) is the production of shade. In the most simplistic terms, making an argument for more long-lived shade via good planting practices in science based suitable soil volumes should be without question. Relative to urban soils, site indexing indicating the ability of a soil to produce and sustain a tree over a given amount of time needs the urban forester's unfettered attention. One certainly should even contemplate the moral dynamics of utilizing only native plant material when a ‘mix-in’ of non-native non-invasive material would further the future of a shade produced and sustained over time. Finally, the essential elements of securing the urban forest for the future must include at the very least the following elements:
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, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or 0.25 CEUs toward BCMA science and 0.25 CEUs toward 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 Dick Miller, Urban Forester - City of Canal Winchester, Ohio
The height of Hawaii’s Mauna Kea from the ocean floor base to the peak at 33,500 feet makes this the world’s tallest mountain from its base to the peak (Mt. Everest reaches the highest elevation). This mass of former molten lava represents a record of the existence of all life on earth. Is it possible to alter the land and air that supports all life from ocean bottom to mountain top of this planet? Can the seven billion (still growing) humans afford to enter uncharted territory as the atmospheric levels of greenhouse gases continue to rise?
Global warming is having an unquestionable impact on forest eco-systems everywhere. The climatic ramifications could be staggering for almost all eco-systems on the planet and one segment of those systems is the urban forest. The future of important urban forest functions includes their effect on stormwater, wildlife management decisions, carbon storage, energy conservation, air quality, continuing an aesthetic sense of place and most importantly the effect that the shaded forest cover will have on the over-all health of this planet. To break it down even further, all forest systems will experience over a relatively short period of time, unknown biological thresholds not experienced in their evolutionary development.
Ecological indicators of change and shifts in species distribution are not new to forest science in the Americas. The decline of quaking aspen (Populus tremuloides), possibly due to effects of climate change in the western U.S., has made news for years. Digging through an outdated Harlow and Harrar 1969 “Textbook of Dendrology”, shows the original range map of P. tremuloides in central/southern Ohio. I can no longer locate the species in that area and native stands apparently are disappearing from northern reaches of the state as well. Also noted by Harlow and Harrar, Ilex opaca (American Holly) in the 200 years prior to the middle of the 20th century, was considered a southern tree. Soon after the beginning of the automobile revolution the species marched steadily northward. The ‘natural shift’ of this plant species toward the north could be due to the warming phenomena in combination with bird species (e.g. northern mockingbird), also simultaneously moving northward that would aid in Ilex seed dissemination.
The primary reason for forest canopy decline where insect and disease are presently moving through forest stands, may be directly related to warming. Simply put, insects and disease are secondary or even tertiary in response to other changes in the forest. Jim Chatfield, associate professor at the Ohio State University notes in 2012 “that the bagworm moth (Thyridoptery x ephemeraeformis) has altered its range due to mild winters in Ohio. Prior to 1980, the insect was rarely able to survive north of the central regions of the state. Now the insect can survive the winters of Michigan.” How a species arrives in a new eco-region by migration or some form of un-natural shift, (e.g. hidden in a wooden shipping pallet of another continental origin), may be inconsequential relative to future survival of the organism. In addition, the native southern pine beetle in the east and native mountain pine beetle in the west are expanding their ranges laterally as well as to higher elevations. All forest types including the urban monocultures are on the brink of succumbing to insects and disease with primary foundations in minute changes in the overall climate.
Urban foresters and others, while not dealing with forest ecosystems that are totally natural, are no less responsible to ensure a viable forest canopy where the most important attribute (relative to the future urban heat island effect) is the production of shade. In the most simplistic terms, making an argument for more long-lived shade via good planting practices in science based suitable soil volumes should be without question. Relative to urban soils, site indexing indicating the ability of a soil to produce and sustain a tree over a given amount of time needs the urban forester's unfettered attention. One certainly should even contemplate the moral dynamics of utilizing only native plant material when a ‘mix-in’ of non-native non-invasive material would further the future of a shade produced and sustained over time. Finally, the essential elements of securing the urban forest for the future must include at the very least the following elements:
- decisions about soil volumes and soil consistency made to withstand the harshest future climate,
- planting a diversity of species paying attention to provenance of those species choices, and
- reducing initial stressors to help insure the future of those plants.
Sources
- Forest Ecology and Management, 2013 vol. 299 pgs. 35-51
- Harlow and Harrar, 1969, Textbook of Dendrology
- Dickerson, 2015 Business Insider. Mt. Everest isn’t the Tallest Mountain.
- Chatfield J. 2012. Presentation live at The Ohio State University Nursery Short Course.
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, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or 0.25 CEUs toward BCMA science and 0.25 CEUs toward 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.
Soil Specification for Urban Tree Installations
Edited by Len Phillips
Global warming has started and one way that arborists can help modify the problem is to plant as many trees as possible. When installing trees in an urban landscape such as a plaza, beside a sidewalk, in the street median or any other location where the disturbed soil will not support plant growth, it is important to specify and install a soil that meets the cultural needs of the tree species. The following are guidelines for the mixing of a soil that will promote growth of most woody landscape plants. This soil is also suitable for the installation in new planting locations in suburban areas, but is not intended for roof top gardens.
Soil Volume Requirements
The amount of soil available will in large part determine the maximum size that the tree will achieve during its growing life span. To determine soil volume required, a tree will need about 5 square feet (0.45 s. meters), 3 feet (1 m.) deep of soil area for each square inch (6.5 s.cm.) of trunk diameter or 15 cubic ft. (4.3 cubic m.) that the tree is anticipated to be at its maximum size. In the urban environment, the essential soil area may need to come from the tree lawn between the street and the sidewalk as well as under and beyond the sidewalk toward private property where there may be better soil.
Soil Depth
Tree roots will seldom grow deeper than 3 feet (1 m). To allow trees to grow to their full potential, the soil must be composed of topsoil and installed in layers. A subsoil mix should be installed first if the planting site is deeper than 3 feet and this should be covered with the topsoil mix. When installing layers, the base soil surface should be tilled or scarified with the teeth of an excavator bucket initially to break up any compaction that is there. Then the topsoil is installed in three or four lifts or layers of less than 12 inches (30 cm) each.
Soil Mix
The top soil may be from either a naturally occurring topsoil or soil that has been mixed to achieve the following specification. Both the top and subsoil should be a sandy loam soil with 50-80% medium and coarse sand (less than 25% fine sand), 5-20% clay, 5-35% silt, compost, or leaf mold.
Stones and Rocks
No stones larger than 1 inch (2.5 cm) in the longest dimension should be permitted. Stones ranging from ½ to 1 inch (1.25 to 2.5 cm) should not exceed 5% of the soil volume, and gravel or coarse sand should not exceed 5% of the soil volume.
Debris Content
Debris is defined as fragments of brick, concrete, wood, glass, metal, stone and plastic greater than 1 inch in the longest dimension. This debris provides no benefit for tree growth. The total volume of debris less than 1 inch long should not be more than 5% of the total soil mix volume.
Contaminants
The soil should have no herbicides, heavy metals, biological toxins, or hydrocarbons that will impact plant growth or are at levels exceeding the EPA’s standards for soil contaminants.
Clod Size
Mixed soils often contain soil clods with a high clay content. Smaller soil peds or lumps that are less than 1 inch long are desirable from a soil drainage perspective and there is no limit on the amount of these small peds contained in the soil mix. Clods from 1-3 inches (2.5-7.5 cm) should make up less than 10% of the soil volume and clods 3-6 inch (7.5-15 cm) should be less than 5%.
Organic Matter Content
Organic matter (OM) is important for retaining water, maintaining stable soil aggregates, promoting biological diversity and providing nutrients for tree growth. The top soil shall have 4-6% OM by weight. If additional organic matter is needed, compost can be added to the soil. A well composted leaf mold, yard waste, or wood chip compost can be used as long as there is no more than 10% OM by volume in the top soil. No soil mix should contain more than 10% compost by volume so as to avoid settling or subsidence problems. Subsoil should have between 1-3% OM, but higher levels are not detrimental.
Density
Soil density needs to be high enough to avoid settling, yet low enough to allow root growth. Top soil should have a density of 1.0 to 1.4 g/cc and subsoil 1.2 to 1.5 g/cc. A vibrating plate compactor may be used between lifts to settle the soil, but only if the engineer on the job demands it.
Drainage
Water should readily drain from the soil. Percolation rates of 1-2 inches (2.5-5 cm) per hour are preferred, if irrigation will be installed during the tree installation process. A drainage system should be installed if the native subsoil has a drainage rate less than 1 inch (2.5 cm) per hour. Corrugated, slotted pipe should be used for drainage. Slots must only be on the bottom half of the pipe. If pipe has slots on the top, plastic sheeting should be taped to the top to keep soil particles from dropping into the pipe.
The drain pipe should be surrounded with coarse sand and should not be wrapped with filter fabric to avoid future clogging problems. The coarse sand trench should be at least 12 inches (30 cm) wide and 10 inches (25 cm) deep, with the pipe in the center. The pipe must go downhill to an appropriate drainage area or municipal stormwater drain system.
If the tree installation is occurring in conjunction with a street drainage improvement project, perforated pipe between the street drain and the planting pit will allow the tree to be watered with street runoff water. A second perforated pipe should be installed near the bottom of the tree pit to collect surplus water and that pipe should be connected to the municipal storm drain or an appropriate drainage area. This process will also clean the street drainage water as it passes through the planting soil.
Soil pH
Soil pH determines the availability of nutrients in the soil. The exact pH range is dependent on the tree species to be planted. Generally, the most desirable pH range is 5.5-6.6 in humid regions (eastern and southern North America, western OR, WA and BC) and 6.0 to 7.4 in arid regions (TX, AZ, and CA). Optimal pH is highly dependent on the tree species to be planted and should be tested and adjusted based on species, prior to planting.
Nutrients
Plant-available nutrients should be tested prior to soil installation. If they are found to be at levels that are listed as “medium” or less on the soil analysis report, the soil should be amended with the appropriate fertilizers. If nitrogen is required, the nitrogen fertilizer shall contain at least 50% of the total N applied in a water insoluble (WIN) form.
Soluble Salt
Soluble salt content shall be less than 2 dS/m. High salt levels can be fatal to most trees and shrubs.
Water
Water is an essential component of keeping new transplants alive and thriving. Soil moisture should be monitored regularly and irrigation applied when needed to assure adequate moisture. Excess irrigation can also harm plants so over irrigation should be avoided. Installation of soil moisture sensors at the time of soil installation is highly recommended.
Pests
With any new planting, the trees and soil moisture should be monitored regularly. Pests can do serious damage to new transplants and are most easily managed before populations build to damaging levels. An Integrated Pest Management (IPM) program is an effective means for protecting new transplants.
Source
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, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or 0.25 CEUs toward BCMA science and 0.25 CEUs toward 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
Global warming has started and one way that arborists can help modify the problem is to plant as many trees as possible. When installing trees in an urban landscape such as a plaza, beside a sidewalk, in the street median or any other location where the disturbed soil will not support plant growth, it is important to specify and install a soil that meets the cultural needs of the tree species. The following are guidelines for the mixing of a soil that will promote growth of most woody landscape plants. This soil is also suitable for the installation in new planting locations in suburban areas, but is not intended for roof top gardens.
Soil Volume Requirements
The amount of soil available will in large part determine the maximum size that the tree will achieve during its growing life span. To determine soil volume required, a tree will need about 5 square feet (0.45 s. meters), 3 feet (1 m.) deep of soil area for each square inch (6.5 s.cm.) of trunk diameter or 15 cubic ft. (4.3 cubic m.) that the tree is anticipated to be at its maximum size. In the urban environment, the essential soil area may need to come from the tree lawn between the street and the sidewalk as well as under and beyond the sidewalk toward private property where there may be better soil.
Soil Depth
Tree roots will seldom grow deeper than 3 feet (1 m). To allow trees to grow to their full potential, the soil must be composed of topsoil and installed in layers. A subsoil mix should be installed first if the planting site is deeper than 3 feet and this should be covered with the topsoil mix. When installing layers, the base soil surface should be tilled or scarified with the teeth of an excavator bucket initially to break up any compaction that is there. Then the topsoil is installed in three or four lifts or layers of less than 12 inches (30 cm) each.
Soil Mix
The top soil may be from either a naturally occurring topsoil or soil that has been mixed to achieve the following specification. Both the top and subsoil should be a sandy loam soil with 50-80% medium and coarse sand (less than 25% fine sand), 5-20% clay, 5-35% silt, compost, or leaf mold.
Stones and Rocks
No stones larger than 1 inch (2.5 cm) in the longest dimension should be permitted. Stones ranging from ½ to 1 inch (1.25 to 2.5 cm) should not exceed 5% of the soil volume, and gravel or coarse sand should not exceed 5% of the soil volume.
Debris Content
Debris is defined as fragments of brick, concrete, wood, glass, metal, stone and plastic greater than 1 inch in the longest dimension. This debris provides no benefit for tree growth. The total volume of debris less than 1 inch long should not be more than 5% of the total soil mix volume.
Contaminants
The soil should have no herbicides, heavy metals, biological toxins, or hydrocarbons that will impact plant growth or are at levels exceeding the EPA’s standards for soil contaminants.
Clod Size
Mixed soils often contain soil clods with a high clay content. Smaller soil peds or lumps that are less than 1 inch long are desirable from a soil drainage perspective and there is no limit on the amount of these small peds contained in the soil mix. Clods from 1-3 inches (2.5-7.5 cm) should make up less than 10% of the soil volume and clods 3-6 inch (7.5-15 cm) should be less than 5%.
Organic Matter Content
Organic matter (OM) is important for retaining water, maintaining stable soil aggregates, promoting biological diversity and providing nutrients for tree growth. The top soil shall have 4-6% OM by weight. If additional organic matter is needed, compost can be added to the soil. A well composted leaf mold, yard waste, or wood chip compost can be used as long as there is no more than 10% OM by volume in the top soil. No soil mix should contain more than 10% compost by volume so as to avoid settling or subsidence problems. Subsoil should have between 1-3% OM, but higher levels are not detrimental.
Density
Soil density needs to be high enough to avoid settling, yet low enough to allow root growth. Top soil should have a density of 1.0 to 1.4 g/cc and subsoil 1.2 to 1.5 g/cc. A vibrating plate compactor may be used between lifts to settle the soil, but only if the engineer on the job demands it.
Drainage
Water should readily drain from the soil. Percolation rates of 1-2 inches (2.5-5 cm) per hour are preferred, if irrigation will be installed during the tree installation process. A drainage system should be installed if the native subsoil has a drainage rate less than 1 inch (2.5 cm) per hour. Corrugated, slotted pipe should be used for drainage. Slots must only be on the bottom half of the pipe. If pipe has slots on the top, plastic sheeting should be taped to the top to keep soil particles from dropping into the pipe.
The drain pipe should be surrounded with coarse sand and should not be wrapped with filter fabric to avoid future clogging problems. The coarse sand trench should be at least 12 inches (30 cm) wide and 10 inches (25 cm) deep, with the pipe in the center. The pipe must go downhill to an appropriate drainage area or municipal stormwater drain system.
If the tree installation is occurring in conjunction with a street drainage improvement project, perforated pipe between the street drain and the planting pit will allow the tree to be watered with street runoff water. A second perforated pipe should be installed near the bottom of the tree pit to collect surplus water and that pipe should be connected to the municipal storm drain or an appropriate drainage area. This process will also clean the street drainage water as it passes through the planting soil.
Soil pH
Soil pH determines the availability of nutrients in the soil. The exact pH range is dependent on the tree species to be planted. Generally, the most desirable pH range is 5.5-6.6 in humid regions (eastern and southern North America, western OR, WA and BC) and 6.0 to 7.4 in arid regions (TX, AZ, and CA). Optimal pH is highly dependent on the tree species to be planted and should be tested and adjusted based on species, prior to planting.
Nutrients
Plant-available nutrients should be tested prior to soil installation. If they are found to be at levels that are listed as “medium” or less on the soil analysis report, the soil should be amended with the appropriate fertilizers. If nitrogen is required, the nitrogen fertilizer shall contain at least 50% of the total N applied in a water insoluble (WIN) form.
Soluble Salt
Soluble salt content shall be less than 2 dS/m. High salt levels can be fatal to most trees and shrubs.
Water
Water is an essential component of keeping new transplants alive and thriving. Soil moisture should be monitored regularly and irrigation applied when needed to assure adequate moisture. Excess irrigation can also harm plants so over irrigation should be avoided. Installation of soil moisture sensors at the time of soil installation is highly recommended.
Pests
With any new planting, the trees and soil moisture should be monitored regularly. Pests can do serious damage to new transplants and are most easily managed before populations build to damaging levels. An Integrated Pest Management (IPM) program is an effective means for protecting new transplants.
Source
- Smiley, E. Thomas, PhD, “Soil for Urban Tree Planting”, Bartlett Research Laboratory Technical Report
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, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or 0.25 CEUs toward BCMA science and 0.25 CEUs toward 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.
Have Two Cities Found the Answer?
Edited by Len Phillips
Louisville, Kentucky
This city has some of the worst air in the country. The reasons for this include the fact that Louisville is a transit hub where tens of thousands of planes, trains, automobiles, and trucks producing air pollutants pass through the city each year. Louisville is also an industrial and manufacturing center where byproducts are released into the air.
This poor air quality has resulted in heart disease, strokes, asthma and other conditions caused by excessive air pollutants found at very high levels. In addition, the city received a failing grade from the American Lung Association in its annual report.
In order to see if trees could help combat the negative health impacts of the city’s deadly air pollution, the University of Louisville Medical Center, the Nature Conservancy, Hyphae Design Laboratory and other organizations came together in the Green Heart project to coordinate a clinical trial to determine if nature could be a pharmaceutical solution.
This ambitious effort conducted a first-of-its-kind medical study by planting trees in strategic locations in the neighborhoods of Louisville for the purpose of observing how trees impact residents’ health. The study was financed by the National Institutes of Health and Louisville-based philanthropies.
The project had its official launch with a community workshop and the start of baseline data collection. Temperatures, particulate matter levels, and volatile organic compounds in the air were all tracked by a network of more than 50 passive air monitors as well as more elaborate monitoring arrays mounted on towers and on an electric car.
Approximately 8,000 trees, shrubs, and other plants were planted in South Louisville, according to a map devised by the Nature Conservancy, and based on data where likely impacts will be of the greatest benefit. As has been noted, trees catch small particulate matter in their leaves, reducing nearby air pollution by a third in some cases; and, if planted near highways, they can act as a buffer, reducing pollution by up to 60 percent.
The next step required 700 neighborhood residents to participate in several rounds of medical tests that began tracking the residual evidence of air pollution in their blood and urine. Different chemical signals were monitored, including the presence of cortisol and adrenaline that are produced when the body is under stress. Participants’ physiological reactions to air pollution were studied for five years, because some compounds appear within hours of exposure while others take months or years to emerge.
The Results – At the end of the five year study, the researchers had a residents’ health data set. They looked at residents before and after the trees were planted, and, for comparison’s sake, data from people who live nearby but didn’t get new trees. The study resulted in a new public health model designed to help reduce urban pollution-related deaths.
The study has positively affected Louisville by reducing health inequities. The life expectancy in the “leafy suburbs” of the city is 13 years longer than in South and West Louisville neighborhoods where lower incomes and less access to nature, prove once again that trees are a reliable indicator of health. The newly-planted trees appeared to have less capacity to catch particulate matter and serve as buffers than mature, fully-grown trees with broad canopies, but the results were still very positive.
The results did show positive benefits from trees and the city government is addressing the inequities and partnering with local community groups to build robust tree canopies all over the city, especially in the neighborhoods that lack them. With solid data, the city will also invest further in the existing urban forest, which annually loses about 55,000 trees from neglect every year city-wide.
Toronto, Ontario
From a similar study of urban trees kept by the city of Toronto, some 530,000 trees were categorized by species, location, and tree diameter. The study findings were not limited to self-perceived health. For cardio-metabolic conditions, a category that includes not only heart disease but stroke, diabetes, obesity and more, this study of Toronto's trees found that an increase of 11 trees per city block was comparable to an increase in annual personal income of $20,000, and moving to a neighborhood with $20,000 higher median income was statistically equal to being 1.4 years younger.
This study was built on a body of prior research showing the cognitive and psychological benefits of natural scenery. But it also goes further by actually beginning to quantify just how much an addition of trees in a neighborhood enhances health outcomes. The researchers were able to do so because they were working with a vast data-set of public and satellite measurements of non-public green space, such as residential back yards. They also had the health records for over 30,000 Toronto residents, reporting not only individual self-perceptions of health but also heart conditions, the prevalence of cancer, diabetes, mental health problems and much more. Most importantly, it seemed like the effect was strongest for the public trees. The fact that street trees seemed to have a more beneficial effect than private or backyard trees may be explained by the fact that they are more accessible to all residents in a given neighborhood.
The results are powerful because of the size of the study. However, the scientists cannot definitively identify the precise mechanism by which trees seem to improve health, but there are some obvious possibilities. Trees are known to improve urban air quality by pulling ozone, particulates, and other pollutants out of the air, and thus, partly protecting people from these problems. Trees are also very calming and play a role of reducing stress which in turn improves the health of Toronto's residents.
Source
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, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA management credits.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or 0.25 CEUs toward BCMA science and 0.25 CEUs toward 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
Louisville, Kentucky
This city has some of the worst air in the country. The reasons for this include the fact that Louisville is a transit hub where tens of thousands of planes, trains, automobiles, and trucks producing air pollutants pass through the city each year. Louisville is also an industrial and manufacturing center where byproducts are released into the air.
This poor air quality has resulted in heart disease, strokes, asthma and other conditions caused by excessive air pollutants found at very high levels. In addition, the city received a failing grade from the American Lung Association in its annual report.
In order to see if trees could help combat the negative health impacts of the city’s deadly air pollution, the University of Louisville Medical Center, the Nature Conservancy, Hyphae Design Laboratory and other organizations came together in the Green Heart project to coordinate a clinical trial to determine if nature could be a pharmaceutical solution.
This ambitious effort conducted a first-of-its-kind medical study by planting trees in strategic locations in the neighborhoods of Louisville for the purpose of observing how trees impact residents’ health. The study was financed by the National Institutes of Health and Louisville-based philanthropies.
The project had its official launch with a community workshop and the start of baseline data collection. Temperatures, particulate matter levels, and volatile organic compounds in the air were all tracked by a network of more than 50 passive air monitors as well as more elaborate monitoring arrays mounted on towers and on an electric car.
Approximately 8,000 trees, shrubs, and other plants were planted in South Louisville, according to a map devised by the Nature Conservancy, and based on data where likely impacts will be of the greatest benefit. As has been noted, trees catch small particulate matter in their leaves, reducing nearby air pollution by a third in some cases; and, if planted near highways, they can act as a buffer, reducing pollution by up to 60 percent.
The next step required 700 neighborhood residents to participate in several rounds of medical tests that began tracking the residual evidence of air pollution in their blood and urine. Different chemical signals were monitored, including the presence of cortisol and adrenaline that are produced when the body is under stress. Participants’ physiological reactions to air pollution were studied for five years, because some compounds appear within hours of exposure while others take months or years to emerge.
The Results – At the end of the five year study, the researchers had a residents’ health data set. They looked at residents before and after the trees were planted, and, for comparison’s sake, data from people who live nearby but didn’t get new trees. The study resulted in a new public health model designed to help reduce urban pollution-related deaths.
The study has positively affected Louisville by reducing health inequities. The life expectancy in the “leafy suburbs” of the city is 13 years longer than in South and West Louisville neighborhoods where lower incomes and less access to nature, prove once again that trees are a reliable indicator of health. The newly-planted trees appeared to have less capacity to catch particulate matter and serve as buffers than mature, fully-grown trees with broad canopies, but the results were still very positive.
The results did show positive benefits from trees and the city government is addressing the inequities and partnering with local community groups to build robust tree canopies all over the city, especially in the neighborhoods that lack them. With solid data, the city will also invest further in the existing urban forest, which annually loses about 55,000 trees from neglect every year city-wide.
Toronto, Ontario
From a similar study of urban trees kept by the city of Toronto, some 530,000 trees were categorized by species, location, and tree diameter. The study findings were not limited to self-perceived health. For cardio-metabolic conditions, a category that includes not only heart disease but stroke, diabetes, obesity and more, this study of Toronto's trees found that an increase of 11 trees per city block was comparable to an increase in annual personal income of $20,000, and moving to a neighborhood with $20,000 higher median income was statistically equal to being 1.4 years younger.
This study was built on a body of prior research showing the cognitive and psychological benefits of natural scenery. But it also goes further by actually beginning to quantify just how much an addition of trees in a neighborhood enhances health outcomes. The researchers were able to do so because they were working with a vast data-set of public and satellite measurements of non-public green space, such as residential back yards. They also had the health records for over 30,000 Toronto residents, reporting not only individual self-perceptions of health but also heart conditions, the prevalence of cancer, diabetes, mental health problems and much more. Most importantly, it seemed like the effect was strongest for the public trees. The fact that street trees seemed to have a more beneficial effect than private or backyard trees may be explained by the fact that they are more accessible to all residents in a given neighborhood.
The results are powerful because of the size of the study. However, the scientists cannot definitively identify the precise mechanism by which trees seem to improve health, but there are some obvious possibilities. Trees are known to improve urban air quality by pulling ozone, particulates, and other pollutants out of the air, and thus, partly protecting people from these problems. Trees are also very calming and play a role of reducing stress which in turn improves the health of Toronto's residents.
Source
- Mooney, Chris, “Energy and Environment”, July 9, 2015.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA management credits.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or 0.25 CEUs toward BCMA science and 0.25 CEUs toward 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.
Urban Tree of the Year – 2020
by Len Phillips
Celtis occidentalis, also called common hackberry does not have the most-lovely name, but it is one very tough tree. This tree, a member of the Ulmaceae family, is native to southeastern Canada and the eastern half of the US and west to Wyoming. In its native range, it prefers to grow in river valleys, though it also grows well in upland mixed forests. Hackberry also grows in rocky, alkaline sites where other trees may struggle. Hackberry can reach 40 to 60 feet ( 12 – 18 m) tall, with a similar spread, resulting in an American elm shape. The Champion Tree, located in Rippon WV has a height of 104 feet (31 m) and spread of 97 feet (29.5 m) and a trunk circumference of 233 inches (6 m). Hackberry is hardy from the cold USDA Hardiness Zone 2 to the sweltering heat of Zone 9 and AHS Heat Zones 9 – 1.
Celtis occidentalis has alternate, simple, ovate, pointed leaves that are 2 to 5 inches (5 to 13 cm) long. The base has one side longer than the other, similar to leaves on elm trees. The leaves are shiny green in color above and pale green on the underside, with glabrous veins. Autumn color may be yellow or yellow-green. Deer will browse on the leaves of hackberry. The wood from hackberry is not used for timber, but it is used as firewood.
The common name hackberry comes from ‘Scottish hagberry,’ which referred to bird cherry (Prunus avium) which has a similar-looking fruit. It is also known as the nettletree, sugarberry, beaverwood, northern hackberry, and American hackberry. Celtis occidentalis can tolerate a variety of conditions, including dry soils and wind, making it an under estimated contributor to the native forest and a good choice to diversify the city forest.
The most handsome hackberry in New York City grows along the Mosholu Parkway where it approaches 80 feet (24 m) in height, with a remarkable American elm-like branching structure.
Lacking a terminal bud, hackberry has a pseudo-terminal bud which is a bud that seems like a terminal bud, but is actually a lateral bud causing the twig to grow in a zig-zag form. The twigs are slender, reddish-brown, and hairy. The pith is white and may be chambered at nodes. The bark of hackberry is smooth and gray when young and develops corky warts with age. As the tree matures, the warts develop into ridges.
Hackberry flowers are polygamo-monecious; meaning male, female, and perfect flowers all on the same tree. Flowers are greenish and not ornamentally important. The fruit, a one-seeded drupe that is orange-red to purple and matures in autumn. The fruits are pea-sized approximately ¼ – ⅓ inch (6 – 8 cm) wide and hang on a pedicel 1 – 2 inches (2 – 5 cm) long. The hackberry's fruit ripen in early September. The fruit can persist through the winter and are favored by people, wildlife, including small mammals and birds. The ripe drupes are high in protein and somewhat sweet. Unlike most fruits, the berries are also remarkably high in calories from fat, carbohydrates, and protein, and these calories are easily digestible without any cooking or preparation. The Omaha Native Americans ate the berries casually, while the Dakota Native Americans used them as a flavoring for meat after pounding them into a fine paste, seeds and all. The Pawnee Native Americans also pounded the berries to a paste, then added a little fat, and mixed them with parched corn which was cooked by dry roasting.
Celtis occidentalis is susceptible to several insects that primarily affect the appearance of the tree. These include a few gall-makers in the genus Pachypsylla, such as the hackberry petiole gall psyllid, the hackberry nipple gall, the hackberry bud gall, and the hackberry blistergall psyllid. Hackberry nipple gall is so often present on the leaves that it can aid identification. The gall ridden leaves are more of an unsightly irritation than they are detrimental to the tree’s health. However, this suggests that the tree should not be grown anywhere that people are looking closely at the leaves. Hackberry is also susceptible to witches’ broom and this can disfigure the tree severely.
There are cultivars that are resistant to witches’ brooms and the nipple gall, including ‘Magnifica,’ which is a vigorous growing cross between C. occidentalis and C. laevigata, (C. laevigata is native to southern United States). Another C. occidentalis cultivar, ‘Prairie Sentinel’ is a columnar form of hackberry. Both cultivars are commonly available in the nursery trade and are preferable for growing as a city tree. Hackberry is only occasionally used as a street or landscape tree, although its tolerance for city conditions makes it well suited for this role.
An historian writes of some large Celtis occidentalis specimens, including a tree trunk over 4 feet (1.2 m) in diameter near Springfield, Massachusetts that was cut down “before the axe of improvement”. It was growing in the middle of the road. Historic street trees were often in the road, growing right there in the dirt. This was before there were automobiles and horse and wagons, so people could easily walk or ride their horses around the trees even when they were growing in the road.
Celtis occidentalis was selected as the 2020 Urban Tree of the Year by a vote from the members of the Society of Municipal Arborists. This tree's popularity comes from the tree's many unique features and its ability to tolerate the urban environment. The increased vigor of ‘Magnifica’ is nice, but comes with a reduced cold hardiness owing to its mixed parentage from C. laevigata, known through the South as sugarberry.
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, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
by Len Phillips
Celtis occidentalis, also called common hackberry does not have the most-lovely name, but it is one very tough tree. This tree, a member of the Ulmaceae family, is native to southeastern Canada and the eastern half of the US and west to Wyoming. In its native range, it prefers to grow in river valleys, though it also grows well in upland mixed forests. Hackberry also grows in rocky, alkaline sites where other trees may struggle. Hackberry can reach 40 to 60 feet ( 12 – 18 m) tall, with a similar spread, resulting in an American elm shape. The Champion Tree, located in Rippon WV has a height of 104 feet (31 m) and spread of 97 feet (29.5 m) and a trunk circumference of 233 inches (6 m). Hackberry is hardy from the cold USDA Hardiness Zone 2 to the sweltering heat of Zone 9 and AHS Heat Zones 9 – 1.
Celtis occidentalis has alternate, simple, ovate, pointed leaves that are 2 to 5 inches (5 to 13 cm) long. The base has one side longer than the other, similar to leaves on elm trees. The leaves are shiny green in color above and pale green on the underside, with glabrous veins. Autumn color may be yellow or yellow-green. Deer will browse on the leaves of hackberry. The wood from hackberry is not used for timber, but it is used as firewood.
The common name hackberry comes from ‘Scottish hagberry,’ which referred to bird cherry (Prunus avium) which has a similar-looking fruit. It is also known as the nettletree, sugarberry, beaverwood, northern hackberry, and American hackberry. Celtis occidentalis can tolerate a variety of conditions, including dry soils and wind, making it an under estimated contributor to the native forest and a good choice to diversify the city forest.
The most handsome hackberry in New York City grows along the Mosholu Parkway where it approaches 80 feet (24 m) in height, with a remarkable American elm-like branching structure.
Lacking a terminal bud, hackberry has a pseudo-terminal bud which is a bud that seems like a terminal bud, but is actually a lateral bud causing the twig to grow in a zig-zag form. The twigs are slender, reddish-brown, and hairy. The pith is white and may be chambered at nodes. The bark of hackberry is smooth and gray when young and develops corky warts with age. As the tree matures, the warts develop into ridges.
Hackberry flowers are polygamo-monecious; meaning male, female, and perfect flowers all on the same tree. Flowers are greenish and not ornamentally important. The fruit, a one-seeded drupe that is orange-red to purple and matures in autumn. The fruits are pea-sized approximately ¼ – ⅓ inch (6 – 8 cm) wide and hang on a pedicel 1 – 2 inches (2 – 5 cm) long. The hackberry's fruit ripen in early September. The fruit can persist through the winter and are favored by people, wildlife, including small mammals and birds. The ripe drupes are high in protein and somewhat sweet. Unlike most fruits, the berries are also remarkably high in calories from fat, carbohydrates, and protein, and these calories are easily digestible without any cooking or preparation. The Omaha Native Americans ate the berries casually, while the Dakota Native Americans used them as a flavoring for meat after pounding them into a fine paste, seeds and all. The Pawnee Native Americans also pounded the berries to a paste, then added a little fat, and mixed them with parched corn which was cooked by dry roasting.
Celtis occidentalis is susceptible to several insects that primarily affect the appearance of the tree. These include a few gall-makers in the genus Pachypsylla, such as the hackberry petiole gall psyllid, the hackberry nipple gall, the hackberry bud gall, and the hackberry blistergall psyllid. Hackberry nipple gall is so often present on the leaves that it can aid identification. The gall ridden leaves are more of an unsightly irritation than they are detrimental to the tree’s health. However, this suggests that the tree should not be grown anywhere that people are looking closely at the leaves. Hackberry is also susceptible to witches’ broom and this can disfigure the tree severely.
There are cultivars that are resistant to witches’ brooms and the nipple gall, including ‘Magnifica,’ which is a vigorous growing cross between C. occidentalis and C. laevigata, (C. laevigata is native to southern United States). Another C. occidentalis cultivar, ‘Prairie Sentinel’ is a columnar form of hackberry. Both cultivars are commonly available in the nursery trade and are preferable for growing as a city tree. Hackberry is only occasionally used as a street or landscape tree, although its tolerance for city conditions makes it well suited for this role.
An historian writes of some large Celtis occidentalis specimens, including a tree trunk over 4 feet (1.2 m) in diameter near Springfield, Massachusetts that was cut down “before the axe of improvement”. It was growing in the middle of the road. Historic street trees were often in the road, growing right there in the dirt. This was before there were automobiles and horse and wagons, so people could easily walk or ride their horses around the trees even when they were growing in the road.
Celtis occidentalis was selected as the 2020 Urban Tree of the Year by a vote from the members of the Society of Municipal Arborists. This tree's popularity comes from the tree's many unique features and its ability to tolerate the urban environment. The increased vigor of ‘Magnifica’ is nice, but comes with a reduced cold hardiness owing to its mixed parentage from C. laevigata, known through the South as sugarberry.
Sources
- J. Frank Schmidt & Son Nursery Fact Sheet, 'Hackberry', 2017.
- Learn 2 Grow, “Celtis occidentalis” Plant Search, 2017.
- Missouri Botannical Garden, Celtis occidentalis, 2018
- Sutton, Michelle, Species Spotlight, The Citizen Forester, January 2020.
- Wikipedia, Celtis occidentalis, July 12, 2018.
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, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Trees with Tales
A Tree's Survival Story
Edited by Len Phillips
Despite the impact that global warming will have on the planet, it is likely that many trees will survive long after humans and many animals have died from excessive heat and oxygen deprivation. An American elm tree (Ulmus americana) just yards away from the explosion during the Oklahoma City bombing should not have survived the blast in 1995. However, this amazing tree not only survived, but it still thrives today and has actually reached “hero” status.
On April 19, 1995, Timothy McVeigh parked a rental truck filled with 4,000 pounds of explosives in front of the Alfred P. Murrah Federal Building. The resulting explosion killed 168 people and destroyed the entire north face of the building. The bomb’s blast was at that time, one of the worst terrorist attacks on American soil.
Right after that fateful day of the bombing, the elm tree was almost chopped down by investigators in their attempt to recover pieces of evidence that hung from its branches. Valuable evidence was also retrieved from the trunk of the tree.
The Survivor Elm Tree has come to stand as a symbol of hope and resilience for an entire community. The elm tree was more than 90 years old when the bomb went off near where it stands. Before the bombing, the tree was important because it provided the only shade in a downtown parking lot. People would arrive early to work just to be able to park in the shade of the elm tree’s branches.
Six hundred and twenty four designs were submitted for a memorial to remember those who died, and in July 1997 a design was chosen. The memorial was to be built in downtown Oklahoma City and called the National Memorial & Museum. It was to be located on the site of the former Murrah Federal Building, which was destroyed beyond repair by the bombing and had to be torn down.
When hundreds of community citizens, family members of those who were killed, survivors and rescue workers came together to write the Memorial Mission Statement, one of its resolutions dictated that “one of the components of the Memorial must be the Survivor Tree located on the south half of the Journal Record Building block.”
Rowland Denman, the Memorial Foundation’s volunteer Executive Director and Richard Williams, District Manager for the General Services Administration, Oklahoma division, called upon the expertise of Mark Bays, an urban forester with the Oklahoma Department of Agriculture, Food and Forestry, to do what he could to save the tree.
Mark took on this project to personally help this tree and began by developing a plan. The asphalt that lined the parking lot was pulled away from the tree so he could begin improving the soil conditions around it. The tree began to thrive and seeds were taken and seedlings were grown in case the tree did not make it or if others wanted a seedling from the survivor tree.
On October 1997, President Bill Clinton signed a law creating the Oklahoma City National Memorial as a unit of the National Park Service to be operated by the Oklahoma City National Memorial Trust. The Memorial design was unveiled the following year, with a prominence put on this old elm. Designers Hans and Torrey Butzer wrote in their plans submitted for the Memorial, “…by creating a level ground plane along Fifth Street, the resulting site contours would emphasize the high point or promontory on which the Survivor Tree now stands. Thus, the Survivor Tree and its cascading terraces became the perfect counter-point to the sloping Murrah Building Footprint across the street.”
Because the roots of the tree ran so deep, the promontory was put on piers so that there would be no damage to the tree’s root system during the memorial construction. The foundation for each pier was hand dug. The design also included an aeration and irrigation system underneath the promontory, which permits the air and water to get to the tree’s roots. This state of the art system allows the tree to receive the appropriate amount of water and air to keep it growing for years to come. The memorial was formally dedicated on April 19, 2000: the fifth anniversary of the bombing. The museum was dedicated and opened the following year on February 19.
Each year, the Facilities and Grounds crew at the Memorial provide nursery men and women with hundreds of seeds from the Survivor Elm. The crew also plants some seeds and distributes the resulting seedlings each year on the anniversary of the bombing. Cuttings and seedlings of the Survivor Tree are now growing in nurseries all over Oklahoma. Owners of nurseries, arborists, urban foresters, and expert horticulturists from across the state and country have come together to work and preserve this piece of history. None of these people have ever charged the Memorial for their work.
Today, thousands of Survivor Trees are growing in public and private places all over the United States. The Survivor Tree is a symbol of human resilience, a hero. As a tribute to renewal and rebirth, the inscription around the tree reads, “The spirit of this city and this nation will not be defeated; our deeply rooted faith sustains us.”
The Oklahoma City National Memorial since its opening has seen over 4.4 million visitors to the Outdoor Symbolic Memorial, 1.6 million visitors to the Memorial Museum, and an unknown number of visitors who sat in the shade of the Survivor tree. The Memorial has an average of 350,000 visitors every year.
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, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or 0.25 CEUs toward BCMA science and 0.25 CEUs toward 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.
A Tree's Survival Story
Edited by Len Phillips
Despite the impact that global warming will have on the planet, it is likely that many trees will survive long after humans and many animals have died from excessive heat and oxygen deprivation. An American elm tree (Ulmus americana) just yards away from the explosion during the Oklahoma City bombing should not have survived the blast in 1995. However, this amazing tree not only survived, but it still thrives today and has actually reached “hero” status.
On April 19, 1995, Timothy McVeigh parked a rental truck filled with 4,000 pounds of explosives in front of the Alfred P. Murrah Federal Building. The resulting explosion killed 168 people and destroyed the entire north face of the building. The bomb’s blast was at that time, one of the worst terrorist attacks on American soil.
Right after that fateful day of the bombing, the elm tree was almost chopped down by investigators in their attempt to recover pieces of evidence that hung from its branches. Valuable evidence was also retrieved from the trunk of the tree.
The Survivor Elm Tree has come to stand as a symbol of hope and resilience for an entire community. The elm tree was more than 90 years old when the bomb went off near where it stands. Before the bombing, the tree was important because it provided the only shade in a downtown parking lot. People would arrive early to work just to be able to park in the shade of the elm tree’s branches.
Six hundred and twenty four designs were submitted for a memorial to remember those who died, and in July 1997 a design was chosen. The memorial was to be built in downtown Oklahoma City and called the National Memorial & Museum. It was to be located on the site of the former Murrah Federal Building, which was destroyed beyond repair by the bombing and had to be torn down.
When hundreds of community citizens, family members of those who were killed, survivors and rescue workers came together to write the Memorial Mission Statement, one of its resolutions dictated that “one of the components of the Memorial must be the Survivor Tree located on the south half of the Journal Record Building block.”
Rowland Denman, the Memorial Foundation’s volunteer Executive Director and Richard Williams, District Manager for the General Services Administration, Oklahoma division, called upon the expertise of Mark Bays, an urban forester with the Oklahoma Department of Agriculture, Food and Forestry, to do what he could to save the tree.
Mark took on this project to personally help this tree and began by developing a plan. The asphalt that lined the parking lot was pulled away from the tree so he could begin improving the soil conditions around it. The tree began to thrive and seeds were taken and seedlings were grown in case the tree did not make it or if others wanted a seedling from the survivor tree.
On October 1997, President Bill Clinton signed a law creating the Oklahoma City National Memorial as a unit of the National Park Service to be operated by the Oklahoma City National Memorial Trust. The Memorial design was unveiled the following year, with a prominence put on this old elm. Designers Hans and Torrey Butzer wrote in their plans submitted for the Memorial, “…by creating a level ground plane along Fifth Street, the resulting site contours would emphasize the high point or promontory on which the Survivor Tree now stands. Thus, the Survivor Tree and its cascading terraces became the perfect counter-point to the sloping Murrah Building Footprint across the street.”
Because the roots of the tree ran so deep, the promontory was put on piers so that there would be no damage to the tree’s root system during the memorial construction. The foundation for each pier was hand dug. The design also included an aeration and irrigation system underneath the promontory, which permits the air and water to get to the tree’s roots. This state of the art system allows the tree to receive the appropriate amount of water and air to keep it growing for years to come. The memorial was formally dedicated on April 19, 2000: the fifth anniversary of the bombing. The museum was dedicated and opened the following year on February 19.
Each year, the Facilities and Grounds crew at the Memorial provide nursery men and women with hundreds of seeds from the Survivor Elm. The crew also plants some seeds and distributes the resulting seedlings each year on the anniversary of the bombing. Cuttings and seedlings of the Survivor Tree are now growing in nurseries all over Oklahoma. Owners of nurseries, arborists, urban foresters, and expert horticulturists from across the state and country have come together to work and preserve this piece of history. None of these people have ever charged the Memorial for their work.
Today, thousands of Survivor Trees are growing in public and private places all over the United States. The Survivor Tree is a symbol of human resilience, a hero. As a tribute to renewal and rebirth, the inscription around the tree reads, “The spirit of this city and this nation will not be defeated; our deeply rooted faith sustains us.”
The Oklahoma City National Memorial since its opening has seen over 4.4 million visitors to the Outdoor Symbolic Memorial, 1.6 million visitors to the Memorial Museum, and an unknown number of visitors who sat in the shade of the Survivor tree. The Memorial has an average of 350,000 visitors every year.
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, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or 0.25 CEUs toward BCMA science and 0.25 CEUs toward 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.
Growing Trees in a City Sidewalk
Edited by Len Phillips
Is there a better way to promote tree root growth in the soil under a city sidewalk and reduce the infrastructure conflicts? Yes!! Is there a way to grow sidewalk trees faster than usual? Yes again!!
A study was concluded in 2015 that compared the effect of various soil treatments on tree growth. This study found that trees will grow better and faster when using the latest developments in growing trees in the city. These treatments included Amsterdam-like soil, two soil cell products, a treatment like Cornell's CU-Structural Soil and two control plots that illustrate current city sidewalk tree installation procedures.
Tom Smiley, the researcher who conducted this effort, objectively compared the growth of trees installed in all these products along with conventional urban street tree installation practices. All of these planting techniques are more expensive than conventional tree installations in existing soil. However, his research demonstrated they are better in terms of supporting long-term tree growth.
He began with Chinese tulip trees Liriodendron chinense being planted in long plots that duplicated a city sidewalk and tree lawn. The soil was 2 feet (60 cm) deep, and 5 feet (1.5 m) wide. At five foot intervals, wood barriers were constructed to separate each of the plots so each plot contained only 42 cubic feet (1.2 cm) of soil, similar to what might be expected in a typical city sidewalk tree pit. The six treatments were duplicated six times to provide replication, so the final growth rates would be an average of the 6 plots.
Treatments
The six different treatments were:
After the trees were planted, a 2 inch (5 cm) layer of concrete was poured over all the plots to replicate a sidewalk, and a 9 inch (22 cm) diameter hole was left in the middle of the plot to accommodate the tree's trunk growth and irrigation.
One year later, each tree's growth data was collected and the tree height, diameter, condition, dieback, and leaf color were all measured. The first year's growth is indicated in the list below.
They were averaged and the 6 soil treatments were compared.
The height and spread of growth for the 2015 growing season numbers clearly illustrate that soil cells out-performed all the other methods.
Soil Cells
The soil cells studied in this research allow for support of the concrete surface, while providing a large less compacted soil volume below the pavement and within the soil cell structure. The two soil cell products available in the U.S. and Canada at the time of this study were:
Both products are placed on a compacted surface at the bottom of the enlarged planting pit. The weight of the pavement and any other surface loading is transferred downward by the cells to the compacted surface at the bottom of the pit while the soil within the cells remains loose and suitable for a tree's root growth. The optimum amount of high quality soil for tree root growth also provides a stormwater reservoir function. Excess water infiltration into the pit escapes through a drain connected to the city storm drain system from the bottom of the pit.
Each soil cell supports the hardscape at the surface and can meet AASHTO H-20 loading requirements with proper engineered surfaces and as reviewed by a qualified engineer. Irrigation and aeration systems as well as local utilities can be integrated into the soil cell layout. Water can also enter the system through pervious paving, drains, catch basins, and the opening around the tree trunk.
Soil cells are not practical for infrastructure replacement projects or around existing trees, unless the utilities are placed in a section where the cells are omitted. Soil cells should be considered for every new, large sidewalk and street tree construction project that has the space for creating 300 cubic feet (8 cubic meters) of soil space or more, and can potentially connect tree planting sites with linear soil volumes.
Tree Valuation
Providing shade in parking lots and near street curbs is a big factor in controlling global warming. Not only does shade drastically improve the shopping experience, it also prolongs the life of the pavement.
In the City of Belmont, Perth, Australia, an asphalt parking lot contains London Plane (Platanus × acerifolia) trees installed with adequate space and soil volume due to the soil cell system beneath the pavement. The cost for installing the five trees (including the soil cell system) was $50,000 or $10,000 per tree. Four years later the trees had grown from a 3” (75mm) trunk diameter at the time of installation, to 10” (250mm). Today, these trees are valued by the City at $17,500 each.
As a comparison, the same council has the same species growing in a nearby parking lot using the conventional installation method. Planted 15 years ago, the same size trees cost $250 per tree and today are valued by the City at $510 each. The tree growth was noticeably less.
Essentially, using the soil vault system, this City was able to grow trees worth 34 times as much in one quarter of the time. This is not just about improving the City's bottom line, but also improving the health and well-being of the communities they serve.
To see a cost comparison of soil cells, see Two Ways to Successful Planting. If you are interested in sending
out a bid to purchase and install soil cells, here is a specification you might want to use.
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, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or 0.25 CEUs toward BCMA science and 0.25 CEUs toward 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
Is there a better way to promote tree root growth in the soil under a city sidewalk and reduce the infrastructure conflicts? Yes!! Is there a way to grow sidewalk trees faster than usual? Yes again!!
A study was concluded in 2015 that compared the effect of various soil treatments on tree growth. This study found that trees will grow better and faster when using the latest developments in growing trees in the city. These treatments included Amsterdam-like soil, two soil cell products, a treatment like Cornell's CU-Structural Soil and two control plots that illustrate current city sidewalk tree installation procedures.
Tom Smiley, the researcher who conducted this effort, objectively compared the growth of trees installed in all these products along with conventional urban street tree installation practices. All of these planting techniques are more expensive than conventional tree installations in existing soil. However, his research demonstrated they are better in terms of supporting long-term tree growth.
He began with Chinese tulip trees Liriodendron chinense being planted in long plots that duplicated a city sidewalk and tree lawn. The soil was 2 feet (60 cm) deep, and 5 feet (1.5 m) wide. At five foot intervals, wood barriers were constructed to separate each of the plots so each plot contained only 42 cubic feet (1.2 cm) of soil, similar to what might be expected in a typical city sidewalk tree pit. The six treatments were duplicated six times to provide replication, so the final growth rates would be an average of the 6 plots.
Treatments
The six different treatments were:
- Compacted control – the soil mix was compacted to 95% Proctor Compaction Test to meet current standards for compaction under streets, sidewalks, and structures – typically found in most cities.
- Silva Cells – the soil mix was compacted to 80% Proctor within the Silva Cell structure.
- StrataCells – the soil mix was installed within the cells at the direction of the manufacturer but the soil density was not tested.
- Sand Based Structural Soil (SBSS) – the soil mix was very similar to Amsterdam soil. The basic formula was 4 parts medium to coarse sand, 1 part topsoil loam and 1.5 parts mature compost. It was compacted to 95% Proctor.
- CU Structural Soil – a small-stone based mix was compacted according to specifications of Cornell University publications. The basic mix was 80% #5 stone, 20% soil mix and 0.003% hydrogel. The mix was compacted to 95% Proctor.
- Control – the parent soil mix was put back in the hole after installation and compacted to 80% Proctor.
After the trees were planted, a 2 inch (5 cm) layer of concrete was poured over all the plots to replicate a sidewalk, and a 9 inch (22 cm) diameter hole was left in the middle of the plot to accommodate the tree's trunk growth and irrigation.
One year later, each tree's growth data was collected and the tree height, diameter, condition, dieback, and leaf color were all measured. The first year's growth is indicated in the list below.
They were averaged and the 6 soil treatments were compared.
- Silva Cells 85 cm (34 inches) height increase, 29 cm (12 inches) branch spread
- StrataCells 88 cm (36 inches) height increase, 25 cm (10 inches) branch spread
- SBSS 42 cm (17 inches) height increase, 18 cm (7 inches) branch spread
- CU Structural Soil 33 cm (13 inches) height increase, 12 cm (5 inches) branch spread
- Control 51 cm (22 inches) height increase, 18 cm (7 inches) branch spread
- Compacted control 9 cm ( 3 inches) height increase, 8 cm (3 inches) branch spread
The height and spread of growth for the 2015 growing season numbers clearly illustrate that soil cells out-performed all the other methods.
Soil Cells
The soil cells studied in this research allow for support of the concrete surface, while providing a large less compacted soil volume below the pavement and within the soil cell structure. The two soil cell products available in the U.S. and Canada at the time of this study were:
- Silva Cells – a type of soil cell that look like industrial shelving and can be stacked to various heights before they are topped with a deck. Each stack is completely open along both vertical and horizontal faces and the stacks stand independently, making future excavation and repairs simple and avoid any impact to the rest of the system. They can be spread laterally as wide as necessary. They are plastic units manufactured by Deep Root.
- StrataCells – manufactured by GreenBlue, are an eight sided “bowl” shaped module with holes on all sides and made from 100% recycled plastic that can be stacked to various heights and cut and shaped as required during construction. All the component modules clip together to form a skeletal matrix which is then filled with soil. This makes for a quick and easy installation. They can also be spread laterally as wide as necessary including under vehicular traffic areas with minimal surface coverage.
Both products are placed on a compacted surface at the bottom of the enlarged planting pit. The weight of the pavement and any other surface loading is transferred downward by the cells to the compacted surface at the bottom of the pit while the soil within the cells remains loose and suitable for a tree's root growth. The optimum amount of high quality soil for tree root growth also provides a stormwater reservoir function. Excess water infiltration into the pit escapes through a drain connected to the city storm drain system from the bottom of the pit.
Each soil cell supports the hardscape at the surface and can meet AASHTO H-20 loading requirements with proper engineered surfaces and as reviewed by a qualified engineer. Irrigation and aeration systems as well as local utilities can be integrated into the soil cell layout. Water can also enter the system through pervious paving, drains, catch basins, and the opening around the tree trunk.
Soil cells are not practical for infrastructure replacement projects or around existing trees, unless the utilities are placed in a section where the cells are omitted. Soil cells should be considered for every new, large sidewalk and street tree construction project that has the space for creating 300 cubic feet (8 cubic meters) of soil space or more, and can potentially connect tree planting sites with linear soil volumes.
Tree Valuation
Providing shade in parking lots and near street curbs is a big factor in controlling global warming. Not only does shade drastically improve the shopping experience, it also prolongs the life of the pavement.
In the City of Belmont, Perth, Australia, an asphalt parking lot contains London Plane (Platanus × acerifolia) trees installed with adequate space and soil volume due to the soil cell system beneath the pavement. The cost for installing the five trees (including the soil cell system) was $50,000 or $10,000 per tree. Four years later the trees had grown from a 3” (75mm) trunk diameter at the time of installation, to 10” (250mm). Today, these trees are valued by the City at $17,500 each.
As a comparison, the same council has the same species growing in a nearby parking lot using the conventional installation method. Planted 15 years ago, the same size trees cost $250 per tree and today are valued by the City at $510 each. The tree growth was noticeably less.
Essentially, using the soil vault system, this City was able to grow trees worth 34 times as much in one quarter of the time. This is not just about improving the City's bottom line, but also improving the health and well-being of the communities they serve.
To see a cost comparison of soil cells, see Two Ways to Successful Planting. If you are interested in sending
out a bid to purchase and install soil cells, here is a specification you might want to use.
Sources
- Gooden, Ben, “Tree Valuation”, Online Seminars #77, January 2018.
- Smiley, E. Thomas, Ph.D., “Comparison of Methods of Soil Management Under Pavement”, Bartlett Tree Research Laboratories, 6/4/2014
- Phillips, Len, “Two Ways to Successful Planting“, Online Seminars Topic #5, 2011.
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, Utility Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or 0.25 CEUs toward BCMA science and 0.25 CEUs toward 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.