Seminar #84 from Online Seminars for Municipal Arborists
October - December 2019
Sections Go directly to the section by clicking on the title below
October - December 2019
Sections Go directly to the section by clicking on the title below
Note: Click on green text in each section for more information and photos.
A Tree Preservation Case Study
By Richard Gibney RLA - ISA
In October 2003, we were called by the landscape architecture firm, TPA Design Group, to inspect two large Copper Beech trees (Fagus sylvatica ‘Atropunicea’) adjacent to a school that was going to be enlarged in two years. The call was to determine if these trees were worth preserving.
Construction of a new addition to the school was anticipated in 2005. The copper beeches were matching 38” (95 cm) caliper trees set symmetrically on either side of a wide concrete entrance walkway that would be converted to an ‘exterior hallway’ connecting the existing structure to the new building, thus forming an “H” shaped complex with the trees in each of the three sided courtyards. Excavations would be necessary on two sides of each tree and well into their root zones. Fortunately, about 70% of the root zones would be left undisturbed. We estimated the age of the trees was more than 60 years old. One of the beech trees was chlorotic and appeared to be lacking the nutrients that the other was getting. It also had several trunk defects that needed further investigation.
We inspected the trees on site, took soil samples, and sent photographs and bark samples of the trees to Cornell University. Cornell’s plant pathology department confirmed that no dangerous pathogens, especially Phytophthora, were present and that the health and vigor of these trees should help them survive a construction project if properly executed. Soil samples revealed that the available nutrients were low and pH was extremely low (4.8). We recommended nutrient amendments using organic products and the addition of dolomitic limestone as soon as possible. The aim was to get increase the pH up to 5.3 or higher for optimum nutrient absorption by the trees. Several applications over time would accomplish this. While many tree species are tough enough to survive adjacent construction, beech trees are especially sensitive to root damage.
That autumn we provided complete specifications for the protection of the trees that included fencing which limited activity surrounding the trees with a total avoidance of activity in the root zone. We recommended the AirSpade® trenching inside the proposed zone of excavation for the new construction would be done in two phases: 10 feet (3m) long by 18 inches (0.5 m) deep trenches set 10 feet apart in the fall and trenching of the remaining 10 foot areas in the spring. As trenches were made, roots would be cut cleanly. The trenches would be backfilled with clean compost and irrigated.
The ideal critical root zone (CRZ) for these trees would have been a 76 foot (21 m) diameter circle, however, construction was to take place well within that zone on two sides of each tree. We were able to protect what might be referred to as the interior CRZ which was about half the ideal CRZ. The size and health of these trees made wind failure a consideration but the adjacent building and proposed extension would provide excellent wind protection on three sides of both trees.
The interior CRZ was covered with 0.5 inches (1.27 cm) of compost followed by a 2 inch (5.08 cm) layer of shredded bark mulch. Autumn leaf drop was shredded and added to the compost. Irrigation was specified to be applied as needed to keep the root zone moist before and during construction. One foot around the root flare was left alone to allow for oxygen exchange and so not to encourage epicormic roots or shoots.
Fortunately for the trees, controversy surrounding the project created a one-year construction delay. This allowed the root pruning project to “rest” for a year so that new roots had the opportunity to develop. The construction eventually took place from late 2005 through 2006.
Care was taken to erect a 6 foot high (1.83 meters) chain link fence around the CRZ prior to construction and was left in place throughout the construction period. Every worker on the project was informed of the goal to preserve these trees. We specified that all the AirSpade® and remedial work was to be done by an ISA Certified Arborist®. The client complied and hired a leading tree care company that employed arborists with ISA credentials. Strong recommendations were made for aftercare, irrigation and follow-up soil testing for the trees. Again, the client complied.
In addition to the fencing, signs were hung on the fence stating what was taking place and instructing all workers on the site to respect the boundaries set up to protect the trees. They also served to inform the public of our client’s intentions to preserve these valuable local assets. The trees remained protected by fencing throughout the construction project and they were visited and inspected by the arborist on a regular basis to check on irrigation and fence integrity.
The overall cost for the tree preservation project exceeded $15,000 USD, and the two priceless trees are thriving as a result. These trees now occupy the two open courtyards within the “H” shaped building where the students can look out the windows to see the magnificence of the copper beech.
We have received communications from school personnel and one particular parent of a student thanking us for the efforts and expressing what a great asset these trees are to the school's aesthetics, environmental education programs, and the overall well-being of the teachers and students. We received photographs annually.
Steps for the Successful Preservation of Trees During and After Construction
- Plans that are developed for construction around valuable trees should take into consideration the trees’
critical root zones (CRZ), which is a circle around the tree with a radius of 1 foot per inch (30 cm per 2.5 cm)
of tree caliper. The more this CRZ is compromised, the lower the chances of tree survival.
- All trees in the vicinity of the construction site should be inspected for health and vitality prior to determining
which trees are valuable enough to be properly preserved.
- Trees under 9 inch (24 cm) caliper can often be transplanted using an AirSpade® (or tree spade or hand
digging) on or off site as a method of preservation. Trees larger than this would require special equipment,
higher cost and longer after care. The costs of transplanting must be weighed against the value of the
tree(s) and the developer’s budget.
- When root damage is inevitable, the arborist or LA must consider the possibility of tree failure not only due to
root loss but failure caused by wind and lack of soil support. Tree support system(s) or root stabilization
might be employed and kept in place temporarily after construction and until it can be determined that the
tree is showing healthy new growth. This could be up to three years or more, although root stabilizers can be
left in place forever.
- Once tree preservation is determined to be a worthy goal, the root system should be protected from that
moment until after construction. If the entire CRZ cannot be protected, it is advisable to root prune the tree
at the closest point outside of the proposed excavation and site disturbance (grading, cutting, filling,
stockpiling, etc.)
- Erection of a sturdy barrier outside the CRZ and/or outside the root pruning trench prior to any construction
activity is essential. Six feet (2 m) high chain link fencing is ideal.
- Soil amendments for proper nutrient balance and optimum pH for the species will promote new, healthy root
growth.
- Lightly mulching the CRZ and providing irrigation during dry spells is highly recommended.
- It is vital to inform everyone involved in the construction project to be aware of the tree preservation efforts.
- No activity is to take place inside the CRZ. This includes vehicle activity, parking, cleaning of equipment,
supply storage, portable toilets, seating for breaks, etc.
- Fencing can only be removed after the construction and all site activity is completed.
- Tree health should be monitored for several years after construction activity by a qualified arborist. A
minimum of two visits annually could determine the onset of any pest or health problems that might be
mitigated.
Richard W. Gibney is a NYS Registered Landscape Architect and ISA Certified Arborist for over three decades.
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 Specialist, Aerial Lift Specialist, or BCMA 0.25 science and 0.25 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.
Women in Arboriculture
Natasa Spica
Natasa Spica works as a landscape architect in public service for the city of JKP “Zelenilo”, in the state of Pancevo, Republic of Serbia, and has had various job positions since 2002. She has worked as an engineer of production, an arborist, a maintenance contractor, a planning consultant, and a designer. Her highest position in JKP “Zelenilo” was the Deputy Head of the Department of Cadastral for Public Green Surfaces. In her free time, beside being a mother of one daughter, she has worked as a florist, a sales person, a driver, and a writer.
For almost two decades, Natasa has been using her skills in GIS Urban Forestry, also known as Cadastre* for urban forestry management and protection. Her specialty involves solving problems and finding new approaches or inventions to reduce tree care and landscape problems. Her duties include creating, recording, and mapping plants, assessing tree health and risk, actual maintenance of vegetation, evaluating grassland conditions, and recording data about species and conditions of individual trees and damages to all the city's landscapes.
Her research effort has taken a bit longer than expected because it raised many new questions about urban vegetation. Many GIS mapping layers were opened and defined. She also started standardizing municipal maps, that might be copied and used in other cities and countries, in principle. After the mapping is completed she plans to continue implementing formulas for biodiversity as it pertains to future tree plantings.
Natasa is using her education and background to observe the conditions of many of the city's trees. Many have signs of risk. She is also evaluating the social-cultural importance of parks and public spaces around collective housing complexes. She has the time to make observations and take actions such removing branches from trees at risk.
While all these skills and duties look good on paper, reality is something else. Ten years ago, Natasa discovered a growing disrespect for the city property and landscapes and this attitude is continuing to grow. There was also an accelerating destruction of public landscapes by private concerns with no objection from the present government.
For a long time, Natasa was silent about the noticeable deterioration and corruption of the government, so she focused on researching Cadastre methods and she developed maps of the landscapes in JKP Zelenilo. She wants to be prepared for the moment when Cadastre will be usable, the people revolt, or the government changes, but all these options may be a losing battle.
Many people in Serbia depend on tourism which is now focused on putting money in private pockets. People are really angry but they do not see change because the government is not responding to citizen complaints. For some, the laws are strict, but for many others, they do not exist.
Most people in Natasa's situation would start applying for jobs in other cities and countries, but there are so few opportunities for a person with her skills, that she has chosen to concentrate on finding solutions and making improvements to the local environment where she is right now. Unfortunately, there are more disappointments and failures than happy moments. But she continues to do her best and looks forward to every spring and a new season of field work.
*Cadastre is defined as an official register of the ownership, extent, and value of real property in a given area.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Natasa Spica
Natasa Spica works as a landscape architect in public service for the city of JKP “Zelenilo”, in the state of Pancevo, Republic of Serbia, and has had various job positions since 2002. She has worked as an engineer of production, an arborist, a maintenance contractor, a planning consultant, and a designer. Her highest position in JKP “Zelenilo” was the Deputy Head of the Department of Cadastral for Public Green Surfaces. In her free time, beside being a mother of one daughter, she has worked as a florist, a sales person, a driver, and a writer.
For almost two decades, Natasa has been using her skills in GIS Urban Forestry, also known as Cadastre* for urban forestry management and protection. Her specialty involves solving problems and finding new approaches or inventions to reduce tree care and landscape problems. Her duties include creating, recording, and mapping plants, assessing tree health and risk, actual maintenance of vegetation, evaluating grassland conditions, and recording data about species and conditions of individual trees and damages to all the city's landscapes.
Her research effort has taken a bit longer than expected because it raised many new questions about urban vegetation. Many GIS mapping layers were opened and defined. She also started standardizing municipal maps, that might be copied and used in other cities and countries, in principle. After the mapping is completed she plans to continue implementing formulas for biodiversity as it pertains to future tree plantings.
Natasa is using her education and background to observe the conditions of many of the city's trees. Many have signs of risk. She is also evaluating the social-cultural importance of parks and public spaces around collective housing complexes. She has the time to make observations and take actions such removing branches from trees at risk.
While all these skills and duties look good on paper, reality is something else. Ten years ago, Natasa discovered a growing disrespect for the city property and landscapes and this attitude is continuing to grow. There was also an accelerating destruction of public landscapes by private concerns with no objection from the present government.
For a long time, Natasa was silent about the noticeable deterioration and corruption of the government, so she focused on researching Cadastre methods and she developed maps of the landscapes in JKP Zelenilo. She wants to be prepared for the moment when Cadastre will be usable, the people revolt, or the government changes, but all these options may be a losing battle.
Many people in Serbia depend on tourism which is now focused on putting money in private pockets. People are really angry but they do not see change because the government is not responding to citizen complaints. For some, the laws are strict, but for many others, they do not exist.
Most people in Natasa's situation would start applying for jobs in other cities and countries, but there are so few opportunities for a person with her skills, that she has chosen to concentrate on finding solutions and making improvements to the local environment where she is right now. Unfortunately, there are more disappointments and failures than happy moments. But she continues to do her best and looks forward to every spring and a new season of field work.
*Cadastre is defined as an official register of the ownership, extent, and value of real property in a given area.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA management credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Urban Tree of Seminar #84
By Len Phillips
Village Green Zelkova Zelkova serrata `Village Green' is a good fit as a street tree. This widely used and very popular cultivar is more upright and faster growing than the species. Foliage is very dense, dark green and presents a clean appearance. It was selected as an outstanding performer by William Flemer, who is featured in another article in this Seminar.
Botanical Name: Zelkova serrata `Village Green'
Common Name: Village Green Zelkova
Botanical Family: Aceraceae
Parentage: Selection from Z. serrata by Princeton Nurseries in 1964
Hardiness Zone: 6 - 8
Mature Size: Height 40' - 60'; Spread 40' - 50'
Plant Patent: #2337
Form: Vase shape in youth, becomes round with age
Flower: Inconspicuous, male only
Fruit: Small drupe
Foliage: Large, 2" - 5" long, dark green leaves, rusty red autumn color
Bark: Straight trunk, smooth and gray, flaky with orange patches on older trunks
Growth Rate: Vigorous, 40' in 30 years
Planting: Transplants easily, install in spring only
Site Requirements: Medium loam, moist, well drained, sun, adapts to all pH, tolerates pollution, drought, wind, and shade
Pest and Disease Resistance: Highly resistant to Dutch Elm Disease (DED) and Elm beetles as well as the Japanese beetle
Storm Resistance: Narrow crotch angles can split in storms
Salt Resistance: Excellent
Other Comments: Wine glass shape like American Elm, short trunk, broader and hardier than `Green Vase' Zelkova, prune young trees in autumn
Available From: Most nurseries
Photo
Sources
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, Utility Specialist, Tree Worker Specialist, Aerial Lift Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Len Phillips
Village Green Zelkova Zelkova serrata `Village Green' is a good fit as a street tree. This widely used and very popular cultivar is more upright and faster growing than the species. Foliage is very dense, dark green and presents a clean appearance. It was selected as an outstanding performer by William Flemer, who is featured in another article in this Seminar.
Botanical Name: Zelkova serrata `Village Green'
Common Name: Village Green Zelkova
Botanical Family: Aceraceae
Parentage: Selection from Z. serrata by Princeton Nurseries in 1964
Hardiness Zone: 6 - 8
Mature Size: Height 40' - 60'; Spread 40' - 50'
Plant Patent: #2337
Form: Vase shape in youth, becomes round with age
Flower: Inconspicuous, male only
Fruit: Small drupe
Foliage: Large, 2" - 5" long, dark green leaves, rusty red autumn color
Bark: Straight trunk, smooth and gray, flaky with orange patches on older trunks
Growth Rate: Vigorous, 40' in 30 years
Planting: Transplants easily, install in spring only
Site Requirements: Medium loam, moist, well drained, sun, adapts to all pH, tolerates pollution, drought, wind, and shade
Pest and Disease Resistance: Highly resistant to Dutch Elm Disease (DED) and Elm beetles as well as the Japanese beetle
Storm Resistance: Narrow crotch angles can split in storms
Salt Resistance: Excellent
Other Comments: Wine glass shape like American Elm, short trunk, broader and hardier than `Green Vase' Zelkova, prune young trees in autumn
Available From: Most nurseries
Photo
Sources
- Dirr, Michael A. and Keith S. Warren, “The Tree Book”, Timber Press, 2019.
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 Specialist, Aerial Lift Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Some Ancient Trees
Edited by Len Phillips
Definitions of what constitutes an oldest-known individual tree varies. Many trees may even be older than their listed ages, especially if the oldest wood in the center of the tree has rotted away, their age cannot be accurately determined. Instead, estimates are made based on the tree's size and presumed growth rate. A series of new studies using alternative techniques such as taking a core from the tree and measuring the rings have demonstrated that using such girth measurements can drastically overestimate the age of a tree, suggesting that many trees are likely much younger than previously reported. Estimates are also derived from a variety of sources such as written documents describing old trees, "tree-ring" counting of a core cross section, and from “historical estimates”. Here are some old trees using these varying criteria.
The oldest known living specimen of Taxodium distichum, commonly called Bald Cypress, is growing in Bladen County, NC. It is over 1,620 years old and one of the oldest living plants in eastern US.
Coast redwood, Sequoia sempervirens, is a long-living evergreen, monoecious tree usually living for 1,200 to 1,800 years or more. The oldest known Sequoia is about 2,200 years old. Coast redwoods are also the tallest living trees on Earth, reaching over 300 feet (90 m) in height and with a spread of 75 feet (20 m). The largest Sequoia populations today are found in Redwood National Park, Muir Woods, and The California Redwood State Parks, where they are protected from logging.
Giant sequoias, Sequoiadendron giganteum, are the world's largest trees by volume and can grow to an average height of 165 – 280 feet (50 – 85 m) and 20 – 25 feet (6 – 8 m) in trunk diameter at breast height (dbh). It occurs only in groves on the western slopes of the Sierra Nevada Mountains of California. Record trees have been measured to be 321 feet (100.5 m) in height and 27 feet (8.2 m) dbh. Sequoia bark is fibrous, furrowed, and may be 3 feet (90 cm) thick at the base of the trunk. The oldest known giant sequoia based on ring count is 3,500 years old.
The Celtics, Druids, and other pagan tribes in England used Taxus baccata, English yew, as places of gathering and often planted yews to form groves within which they would worship. Druids were forbidden from worshiping their gods inside an enclosed building, so they worshiped in the open air. Most of their sacred sites were on elevated ground, closer to the heavenly bodies that they worshiped, and where they could be seen most clearly. Yews are also found in the main squares of the villages where people celebrated the open councils that served as a general assembly to rule the village affairs.
Until now, the ages of some of Britain’s best-loved trees, including yews, sweet chestnuts and oaks, have largely been estimated from measuring the girth of their trunks. These are measurements which often result in a tree being declared hundreds or sometimes thousands of years old. But the age of a yew is impossible to determine accurately because there is rarely any solid trunk wood. Even the branches become hollow with age. Evidence of their age is based on growth rates and archaeological work of the surrounding structures.
The Ankerwycke Yew is an ancient yew tree close to the ruins of St Mary's Priory, the site of a Benedictine nunnery built in the 12th century, near Wraysbury in Berkshire, England. It is a male tree with a girth of 26 ft (8 meters) at one foot (0.3 meters) above the ground level. The tree is at least 1,400 years old, and could be as old as 2,500 years. The Ankerwycke Yew is situated on lands managed by the National Trust of the UK. In 2002 it was designated one of fifty Great British Trees, by The Tree Council. On the opposite bank of the adjacent River Thames are the meadows of Runnymede and this tree is said to have been witness to the signing of Magna Carta. There is some justification for the theory that the Ankerwycke Yew could be 'the last surviving witness to the sealing of the Magna Carta 800 years ago'. It is also said to be the location where Henry VIII met Anne Boleyn in the 1530s. The 13th Century landscape would have been different as the area was probably rather marshy as it was within the flood plain of the Thames. The Ankerwycke Yew is on a slightly raised area of land (therefore dry) and with the proximity of the Priory, perhaps both lend some credibility to this claim of survival and old age.
Another Taxus baccata, reported to be 3,000 years old, is the Ashbrittle Yew which stands in the churchyard of St John the Baptist, in Ashbrittle. With a branch circumference of 38 feet (12 m), this yew is reportedly situated on a Bronze Age mound where a pre-Roman chief is buried.
However, the evidence suggests that the oldest known Taxus baccata is the Fortingall Yew in Perthshire, Scotland, estimated between 3,000 to 9,000 years old, but most likely 5,000 years of age, making it the oldest tree in Europe. One characteristic contributing to the yew's longevity is that it was able to split under the weight of advanced growth without succumbing to disease in the fracture, as do most other trees. Another factor contributing to its age is its ability to grow new epicormic and basal shoots from cut surfaces and on low portions of its trunk, even at an old age.
The current record-holders for individual, non-clonal trees are the Pinus longaeva, the Great Basin bristlecone pine trees from California and Nevada, in the United States. Through tree-ring cross-referencing, this tree has been shown to be more than 5,000 years old. making it the oldest known individual of any species on Earth.
A clonal colony of trees can survive for a much longer time than an individual tree. A colony of Huon pine Lagarostrobos franklinii, is a species of conifer native to the wet southwestern corner of Tasmania, Australia. Huon pine trees covering 2.5 acres (1.0 ha) on Mount Read, Tasmania and are estimated to be around 10,000 years old, as determined by DNA samples taken from pollen collected from the sediment of a nearby lake. Individual trees in this group date to no more than 4,000 years old, as determined by tree ring samples.
A clonal colony of 47,000 male quaking aspen, Populus tremuloides, trees (nicknamed Pando), covers 106 acres (43 ha) in the Fishlake National Forest of Utah. It is considered one of the oldest and largest organisms in the world. The colony has been estimated to be 80,000 years old, although tree ring samples date individual, above-ground, trees at only an average of about 130 years. During intense fires, the organism survived underground, with its root system sending up new stems in the aftermath of each wildfire. If its postulated age is correct, the climate into which Pando was born in was markedly different from that of today, and it may have been as many as 10,000 years since Pando's last successful flowering. A study published in October 2018 concludes that Pando has not been growing for the past 30 – 40 years. Human interference was named as the primary cause, with the study specifically citing people allowing cattle and deer populations to thrive, their grazing resulting in fewer saplings to replace the dying trees.
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, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
Definitions of what constitutes an oldest-known individual tree varies. Many trees may even be older than their listed ages, especially if the oldest wood in the center of the tree has rotted away, their age cannot be accurately determined. Instead, estimates are made based on the tree's size and presumed growth rate. A series of new studies using alternative techniques such as taking a core from the tree and measuring the rings have demonstrated that using such girth measurements can drastically overestimate the age of a tree, suggesting that many trees are likely much younger than previously reported. Estimates are also derived from a variety of sources such as written documents describing old trees, "tree-ring" counting of a core cross section, and from “historical estimates”. Here are some old trees using these varying criteria.
The oldest known living specimen of Taxodium distichum, commonly called Bald Cypress, is growing in Bladen County, NC. It is over 1,620 years old and one of the oldest living plants in eastern US.
Coast redwood, Sequoia sempervirens, is a long-living evergreen, monoecious tree usually living for 1,200 to 1,800 years or more. The oldest known Sequoia is about 2,200 years old. Coast redwoods are also the tallest living trees on Earth, reaching over 300 feet (90 m) in height and with a spread of 75 feet (20 m). The largest Sequoia populations today are found in Redwood National Park, Muir Woods, and The California Redwood State Parks, where they are protected from logging.
Giant sequoias, Sequoiadendron giganteum, are the world's largest trees by volume and can grow to an average height of 165 – 280 feet (50 – 85 m) and 20 – 25 feet (6 – 8 m) in trunk diameter at breast height (dbh). It occurs only in groves on the western slopes of the Sierra Nevada Mountains of California. Record trees have been measured to be 321 feet (100.5 m) in height and 27 feet (8.2 m) dbh. Sequoia bark is fibrous, furrowed, and may be 3 feet (90 cm) thick at the base of the trunk. The oldest known giant sequoia based on ring count is 3,500 years old.
The Celtics, Druids, and other pagan tribes in England used Taxus baccata, English yew, as places of gathering and often planted yews to form groves within which they would worship. Druids were forbidden from worshiping their gods inside an enclosed building, so they worshiped in the open air. Most of their sacred sites were on elevated ground, closer to the heavenly bodies that they worshiped, and where they could be seen most clearly. Yews are also found in the main squares of the villages where people celebrated the open councils that served as a general assembly to rule the village affairs.
Until now, the ages of some of Britain’s best-loved trees, including yews, sweet chestnuts and oaks, have largely been estimated from measuring the girth of their trunks. These are measurements which often result in a tree being declared hundreds or sometimes thousands of years old. But the age of a yew is impossible to determine accurately because there is rarely any solid trunk wood. Even the branches become hollow with age. Evidence of their age is based on growth rates and archaeological work of the surrounding structures.
The Ankerwycke Yew is an ancient yew tree close to the ruins of St Mary's Priory, the site of a Benedictine nunnery built in the 12th century, near Wraysbury in Berkshire, England. It is a male tree with a girth of 26 ft (8 meters) at one foot (0.3 meters) above the ground level. The tree is at least 1,400 years old, and could be as old as 2,500 years. The Ankerwycke Yew is situated on lands managed by the National Trust of the UK. In 2002 it was designated one of fifty Great British Trees, by The Tree Council. On the opposite bank of the adjacent River Thames are the meadows of Runnymede and this tree is said to have been witness to the signing of Magna Carta. There is some justification for the theory that the Ankerwycke Yew could be 'the last surviving witness to the sealing of the Magna Carta 800 years ago'. It is also said to be the location where Henry VIII met Anne Boleyn in the 1530s. The 13th Century landscape would have been different as the area was probably rather marshy as it was within the flood plain of the Thames. The Ankerwycke Yew is on a slightly raised area of land (therefore dry) and with the proximity of the Priory, perhaps both lend some credibility to this claim of survival and old age.
Another Taxus baccata, reported to be 3,000 years old, is the Ashbrittle Yew which stands in the churchyard of St John the Baptist, in Ashbrittle. With a branch circumference of 38 feet (12 m), this yew is reportedly situated on a Bronze Age mound where a pre-Roman chief is buried.
However, the evidence suggests that the oldest known Taxus baccata is the Fortingall Yew in Perthshire, Scotland, estimated between 3,000 to 9,000 years old, but most likely 5,000 years of age, making it the oldest tree in Europe. One characteristic contributing to the yew's longevity is that it was able to split under the weight of advanced growth without succumbing to disease in the fracture, as do most other trees. Another factor contributing to its age is its ability to grow new epicormic and basal shoots from cut surfaces and on low portions of its trunk, even at an old age.
The current record-holders for individual, non-clonal trees are the Pinus longaeva, the Great Basin bristlecone pine trees from California and Nevada, in the United States. Through tree-ring cross-referencing, this tree has been shown to be more than 5,000 years old. making it the oldest known individual of any species on Earth.
A clonal colony of trees can survive for a much longer time than an individual tree. A colony of Huon pine Lagarostrobos franklinii, is a species of conifer native to the wet southwestern corner of Tasmania, Australia. Huon pine trees covering 2.5 acres (1.0 ha) on Mount Read, Tasmania and are estimated to be around 10,000 years old, as determined by DNA samples taken from pollen collected from the sediment of a nearby lake. Individual trees in this group date to no more than 4,000 years old, as determined by tree ring samples.
A clonal colony of 47,000 male quaking aspen, Populus tremuloides, trees (nicknamed Pando), covers 106 acres (43 ha) in the Fishlake National Forest of Utah. It is considered one of the oldest and largest organisms in the world. The colony has been estimated to be 80,000 years old, although tree ring samples date individual, above-ground, trees at only an average of about 130 years. During intense fires, the organism survived underground, with its root system sending up new stems in the aftermath of each wildfire. If its postulated age is correct, the climate into which Pando was born in was markedly different from that of today, and it may have been as many as 10,000 years since Pando's last successful flowering. A study published in October 2018 concludes that Pando has not been growing for the past 30 – 40 years. Human interference was named as the primary cause, with the study specifically citing people allowing cattle and deer populations to thrive, their grazing resulting in fewer saplings to replace the dying trees.
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, 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.
Planning the Urban Forest
Edited by Len Phillips
Today more people are choosing to live in urban areas than ever before. This requires more housing, better transportation, and up-to-date public services to support growing populations, which have negative impacts on air and water quality, and reduced access to natural environments. In addition, climate change is creating new realities like urban hot spots and rising sea levels, demanding more creativity from arborists who must make sure urban areas are suitable for trees and livable for residents. In response, city governments around the world are investing in public green spaces and tree care programs as a requirement of urban livability.
In Shanghai, the Huangpu River is lined with ferry docks, commercial buildings, a cement plant, and construction sites. To reconnect residents to the waterfront and improve urban livability, the city proposed creating the world’s largest urban forest along the east bank of the Huangpu River, winning an international award for the concept. Understanding that cities and their surrounding environments are constantly changing, this project was designed so that the waterfront today will be useful today and that future generations will still be able to use this waterfront. This effort ensures that no matter how Shanghai changes, residents will always have access to the natural, recreational spaces they need.
The project detailed a continuous woodland of two million trees, one tree planted for each of Shanghai’s two million children. While it is estimated that this effort would take 20 years to complete, the children represented by the forest would grow with it, coming of age at the same time of the project’s completion.
To give Shanghai’s young population a sense of ownership over their city and the project, the proposal features a series of tree planting events, allowing local schools to participate in the creation and custodianship of the forest. The project also contains a series of multi-functional events so that the community could host a wide variety of cultural gatherings.
Specifically, the urban forest would contain a multitude of different destinations, ranging from large, dramatic event spaces, to sporting facilities for locals, outdoor classrooms, libraries, and restaurants. A system of elevated walking loops would help overcome industrial and transportation barriers along the waterfront that had previously restricted public access. While the city provided the landscape, the residents will ultimately bring the space to life, so it must be able to accommodate a variety of cultural activities.
This approach is taking hold worldwide. For example, in the San Francisco Bay Area, a similar community-based approach combined the expertise and experience of residents, public officials and local, national and international experts to come up with community-based solutions to the sea level rise, the severe storms, the flooding, and the earthquakes that threaten communities throughout the Bay Area.
Before it became known as the Bay Area’s ‘industrial city’, the residents of South San Francisco could walk the length of nearby Colma Creek and swim in the San Francisco Bay. However, today, industry limits access to the shoreline and sea level rise, fueled by climate change that causes widespread and damaging floods. Through community engagement and research, a range of ways were prepared to strengthen the city of South San Francisco from the effects of climate change. The final proposal restores public access to the waterfront, establishes more open green spaces and parks, and creates continuous public access along Colma Creek. This effort addresses the impacts of climate change that the community will face in the coming decades.
South San Francisco's plan includes a wider, greener creek that would manage flooding and create the right conditions for a sequence of new parks on either side of the creek. There will be a new South City Circle Bridge that would serve as a walking and cycling gateway between the city and the train stop nearby, and a native plant nursery just below the bridge to help control flooding and treat runoff from the nearby highway, improving the quality of water flowing into the creek and Bay. Finally, there will be an ‘eco waterpark’ at a revamped, natural water plant, which would not only improve water quality but also become a teaching tool and natural shoreline swimming pool for the community to enjoy.
Other cities around the world are investing in public green spaces, and their longevity is determined by their ability to be adaptable and serve a multitude of purposes. In Shanghai, the waterfront is not just a walking path, but a series of cultural event venues for gatherings large and small. In South San Francisco, a park is not just a place to play and enjoy nature, but a way to manage flooding and improve water quality. By listening to the needs of the local communities, arborists, designers, and architects are creating spaces that can be enjoyed by the generations of today and tomorrow.
Source
Alcide, Matt, “An Urban Forest for Shanghai” Land 8, December 2, 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, or BCMA 0.25 practice and 0.25 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
Today more people are choosing to live in urban areas than ever before. This requires more housing, better transportation, and up-to-date public services to support growing populations, which have negative impacts on air and water quality, and reduced access to natural environments. In addition, climate change is creating new realities like urban hot spots and rising sea levels, demanding more creativity from arborists who must make sure urban areas are suitable for trees and livable for residents. In response, city governments around the world are investing in public green spaces and tree care programs as a requirement of urban livability.
In Shanghai, the Huangpu River is lined with ferry docks, commercial buildings, a cement plant, and construction sites. To reconnect residents to the waterfront and improve urban livability, the city proposed creating the world’s largest urban forest along the east bank of the Huangpu River, winning an international award for the concept. Understanding that cities and their surrounding environments are constantly changing, this project was designed so that the waterfront today will be useful today and that future generations will still be able to use this waterfront. This effort ensures that no matter how Shanghai changes, residents will always have access to the natural, recreational spaces they need.
The project detailed a continuous woodland of two million trees, one tree planted for each of Shanghai’s two million children. While it is estimated that this effort would take 20 years to complete, the children represented by the forest would grow with it, coming of age at the same time of the project’s completion.
To give Shanghai’s young population a sense of ownership over their city and the project, the proposal features a series of tree planting events, allowing local schools to participate in the creation and custodianship of the forest. The project also contains a series of multi-functional events so that the community could host a wide variety of cultural gatherings.
Specifically, the urban forest would contain a multitude of different destinations, ranging from large, dramatic event spaces, to sporting facilities for locals, outdoor classrooms, libraries, and restaurants. A system of elevated walking loops would help overcome industrial and transportation barriers along the waterfront that had previously restricted public access. While the city provided the landscape, the residents will ultimately bring the space to life, so it must be able to accommodate a variety of cultural activities.
This approach is taking hold worldwide. For example, in the San Francisco Bay Area, a similar community-based approach combined the expertise and experience of residents, public officials and local, national and international experts to come up with community-based solutions to the sea level rise, the severe storms, the flooding, and the earthquakes that threaten communities throughout the Bay Area.
Before it became known as the Bay Area’s ‘industrial city’, the residents of South San Francisco could walk the length of nearby Colma Creek and swim in the San Francisco Bay. However, today, industry limits access to the shoreline and sea level rise, fueled by climate change that causes widespread and damaging floods. Through community engagement and research, a range of ways were prepared to strengthen the city of South San Francisco from the effects of climate change. The final proposal restores public access to the waterfront, establishes more open green spaces and parks, and creates continuous public access along Colma Creek. This effort addresses the impacts of climate change that the community will face in the coming decades.
South San Francisco's plan includes a wider, greener creek that would manage flooding and create the right conditions for a sequence of new parks on either side of the creek. There will be a new South City Circle Bridge that would serve as a walking and cycling gateway between the city and the train stop nearby, and a native plant nursery just below the bridge to help control flooding and treat runoff from the nearby highway, improving the quality of water flowing into the creek and Bay. Finally, there will be an ‘eco waterpark’ at a revamped, natural water plant, which would not only improve water quality but also become a teaching tool and natural shoreline swimming pool for the community to enjoy.
Other cities around the world are investing in public green spaces, and their longevity is determined by their ability to be adaptable and serve a multitude of purposes. In Shanghai, the waterfront is not just a walking path, but a series of cultural event venues for gatherings large and small. In South San Francisco, a park is not just a place to play and enjoy nature, but a way to manage flooding and improve water quality. By listening to the needs of the local communities, arborists, designers, and architects are creating spaces that can be enjoyed by the generations of today and tomorrow.
Source
Alcide, Matt, “An Urban Forest for Shanghai” Land 8, December 2, 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, or BCMA 0.25 practice and 0.25 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.
Provenance
Edited by Len Phillips
There are two different methods to improve trees for nursery sales and growth in our cities:
What is Provenance? According to the Arborist Dictionary, provenance refers to the source of a tree such as regional seed sources or ecotypes within a species. Provenance in forestry refers to the particular place where trees are growing naturally or the place of origin of seeds from select trees. Provenance may refer either to native or to planted trees growing at that place, but its common use is in reference to native trees. According to Dirr & Warren's “The Tree Book”, provenance indicates regional differences in appearance and adaptability within a species. In other words, it is easy to understand that a red maple seedling is going to grow differently in Florida than a red maple seedling growing in New England. Ancient woodlands represent our closest link with 'wildwood' of early history. The small fragments of ancient semi-natural woodland that still exist are unique. These differences may apply to cold and heat tolerance, growth rate, wet and dry soil tolerances, insect and diseases resistance, and many other factors.
Many of the tree species common to our urban forests have wide natural ranges which cover many different habitats and climatic zones. Trees have adapted to these conditions and as a result they can have very different characteristics depending on the origin of the seed source. For example, Douglasfir have natural ranges that cover large areas of western North America, from moist coastal regions to high altitude dry interior mountain ranges, and from northern to the start of southern latitudes. They have developed characteristics that allow them to survive and grow in these varied conditions, and depending on which region the seed is collected from, the performance of the trees from these various seed sources can be very different when grown somewhere else. To determine the best sources, seed origin or provenance, studies have been carried out by the USDA Forest Service since the early 1960s in their attempt to develop trees that will thrive in very specific locations.
Provenance is as important to horticulturalists as it is to arborists. It is becoming more important to both professions for dealing with the effects of global warming. Generally, local seed sources are better for local plantings and forest restoration efforts. While trees originating in hot locations might be better seed sources if the tree is to be planted at an urban site where future global warming is being considered.
In urban tree settings, provenance plays a very important role because of altered soils, restricted root space, poor drainage, and hotter sites. Local nursery trees may not be suitable for growing in the city. This is when trees originating in a more stressful location such as a hot, dry desert site would likely perform better than pampered trees growing locally.
An excellent example of this feature is the City Slicker® Birch tree described elsewhere in this Seminar. The toughness of the birch to withstand heat and drought in Oklahoma make it a great tree for growing in hot cities around the world dealing with global warming.
While local nurseries were the best sources for native trees, the nursery industry has moved toward cultivar production because cities and sales have embraced this. Cultivar production offers the reliability of known performance and lessens the uncertainty inherent in a local seedling. If a tree has become labeled as a cultivar with known traits, the arborist can use this information when selecting the site for a specific tree or picking the right tree for a specific site.
Provenance is a powerful tool to use for tree improvement and a greater emphasis should be placed on it by those breeding and selecting new cultivars as well as by those purchasing and installing trees. Within forest populations (unimproved stands, seed stands or families) individuals are often found with outstanding characteristics which are far superior to the rest. Tree breeders select and propagate these individuals to produce superior clonal varieties with the same traits as the parent trees. In developing these varieties it is necessary to test the performance of the clones to ensure that they are indeed superior and will perform consistently over a range of site types.
Sources
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA 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
There are two different methods to improve trees for nursery sales and growth in our cities:
- Provenance refers to studies that identify selected trees from wild populations.
- Tree breeding programs will select and breed from the best individuals within a tree population.
What is Provenance? According to the Arborist Dictionary, provenance refers to the source of a tree such as regional seed sources or ecotypes within a species. Provenance in forestry refers to the particular place where trees are growing naturally or the place of origin of seeds from select trees. Provenance may refer either to native or to planted trees growing at that place, but its common use is in reference to native trees. According to Dirr & Warren's “The Tree Book”, provenance indicates regional differences in appearance and adaptability within a species. In other words, it is easy to understand that a red maple seedling is going to grow differently in Florida than a red maple seedling growing in New England. Ancient woodlands represent our closest link with 'wildwood' of early history. The small fragments of ancient semi-natural woodland that still exist are unique. These differences may apply to cold and heat tolerance, growth rate, wet and dry soil tolerances, insect and diseases resistance, and many other factors.
Many of the tree species common to our urban forests have wide natural ranges which cover many different habitats and climatic zones. Trees have adapted to these conditions and as a result they can have very different characteristics depending on the origin of the seed source. For example, Douglasfir have natural ranges that cover large areas of western North America, from moist coastal regions to high altitude dry interior mountain ranges, and from northern to the start of southern latitudes. They have developed characteristics that allow them to survive and grow in these varied conditions, and depending on which region the seed is collected from, the performance of the trees from these various seed sources can be very different when grown somewhere else. To determine the best sources, seed origin or provenance, studies have been carried out by the USDA Forest Service since the early 1960s in their attempt to develop trees that will thrive in very specific locations.
Provenance is as important to horticulturalists as it is to arborists. It is becoming more important to both professions for dealing with the effects of global warming. Generally, local seed sources are better for local plantings and forest restoration efforts. While trees originating in hot locations might be better seed sources if the tree is to be planted at an urban site where future global warming is being considered.
In urban tree settings, provenance plays a very important role because of altered soils, restricted root space, poor drainage, and hotter sites. Local nursery trees may not be suitable for growing in the city. This is when trees originating in a more stressful location such as a hot, dry desert site would likely perform better than pampered trees growing locally.
An excellent example of this feature is the City Slicker® Birch tree described elsewhere in this Seminar. The toughness of the birch to withstand heat and drought in Oklahoma make it a great tree for growing in hot cities around the world dealing with global warming.
While local nurseries were the best sources for native trees, the nursery industry has moved toward cultivar production because cities and sales have embraced this. Cultivar production offers the reliability of known performance and lessens the uncertainty inherent in a local seedling. If a tree has become labeled as a cultivar with known traits, the arborist can use this information when selecting the site for a specific tree or picking the right tree for a specific site.
Provenance is a powerful tool to use for tree improvement and a greater emphasis should be placed on it by those breeding and selecting new cultivars as well as by those purchasing and installing trees. Within forest populations (unimproved stands, seed stands or families) individuals are often found with outstanding characteristics which are far superior to the rest. Tree breeders select and propagate these individuals to produce superior clonal varieties with the same traits as the parent trees. In developing these varieties it is necessary to test the performance of the clones to ensure that they are indeed superior and will perform consistently over a range of site types.
Sources
- Dirr, Michael A. and Keith S. Warren, “The Tree Book”, Timber Press, 2019.
- The Conservation Volunteers, “Why plant native trees of local provenance?”, 2003.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Trees with Tales
By Len Phillips
The Tree
Betula nigra 'WhitXXV', PP16573, given the trademark name of City Slicker® Birch, is noted for its heat tolerance, good vigor, and the best drought resistance of all the river birch cultivars. The lustrous, dark green leaves are covered with surface waxes that enhance the drought resistance. The leaves turn a beautiful golden yellow in autumn.
The canopy of Betula nigra 'WhitXXV' will develop an oval form. This tree is said to be unattractive to deer and resistant to borers. It is a low maintenance tree and grows at a medium to fast rate. City Slicker® Birch prefers a moist soil but will tolerate periods of drought. It does well in light shade as well as full sun. Betula nigra ‘WHIT XXV’ has not been observed under all possible environmental conditions yet, but understand that the appearance may vary significantly with variations in soils, temperature, light intensity, and length of day, without any differences in the genetics of the tree and will do well throughout most of the U.S.
Male and female flowers appear in separate catkins on the same tree. The male flowers are characterized as hanging clusters of slender, shiny dark brown catkins that are between 1.5 in (4 cm) and 2.5 in (6 cm) long. The female flowers are characterized as being in upright green catkins that are between 0.15 and 0.4 inches (0.4 – 1 cm) long.
The Tales
While exploring botanical archives, Carl Whitcomb learned that during the last ice age, 30 or more species of birch trees were forced to migrate southward but only river birch, Betula nigra, remained in the south as temperatures warmed and the glaciers retreated. For some reason the river birch were the only species that tolerated the heat and avoided being attacked by the bronze birch borer.
Carl was interested in this so in the spring of 1986, he began to explore some of the western most native river birch trees located in central Oklahoma. These trees appeared to have exceptional heat and drought tolerance as they were growing along a narrow stream bed that was dry most of the year. The trees were small in stature with bark slightly lighter than typical river birch. A soil sample from near the trees showed alkaline soil with low nutrient levels, especially phosphorus, iron and manganese.
Seeds were collected in the spring of 1986, but none germinated. The process was repeated in 1987 and approximately three pounds of seeds were gathered (there are about 375,000 seeds per pound). From this seed lot, only a small fraction of the seeds germinated and most were weak and did not survive the first summer. There were, however three vigorous seedlings that were planted into a field and allowed to grow. Of these three seedlings, two were loose and open branched trees typical of the species and of little interest. The other seedling was more ornamental with denser branching, darker leaves and slightly slower growing. When this unusual seedling was six years old, seeds were produced and all were collected and planted. Many seedlings were weak and did not survive but about 600 seedlings were judged to have acceptable vigor and were planted in the field and allowed to grow. After five years, the seedling with the lightest bark produced viable seed which were collected and planted. Only 67 plants resulted, but one of the fourth generation seedlings had distinctly dark green leaves on dense branches well distributed around the main stems and when a stem reached about ¾ to 1 inch (2-3 cm) in diameter it began to peel. The inner bark was white. Today this seedling is nearly ten inches in diameter at the base and the bark remains white during fall and winter (it is necessary for light to contact the bark to shift to the white color). This unique seedling was given the cultivar name ‘Whit XXV’ and the registered trademark name City Slicker®. The USA Plant Patent #16573 has been awarded to this tree.
Cuttings from City Slicker® birch do produce roots and grow with vigor both in containers and in the field. Little effort is required to form an attractive multiple stem tree. Propagation procedures by tissue culture have been worked out and liners are available. Two trees were planted at a site in Fort Atkinson, Wisconsin in 2002 and survived a January 2019 temperature of -21° F (-30°C) with no winter damage. Under Oklahoma conditions City Slicker® is more heat and drought tolerant than Heritage® or Dura-Heat® cultivars and many other trees. Leaves of City Slicker® are smaller and darker green than Heritage, but slightly larger than Dura-Heat under the same conditions.
During the severe summer drought of 2011, the greater drought tolerance of City Slicker® was distinct. City Slicker® appears to have a range of adaptation from hardiness zones 5 (but most likely 4) through 9 and growth estimates are that it will reach a maximum height in the 30 to 40 foot (9–12 m) range with a 20 to 25 foot (6–8 m) spread. City Slicker® is one of the most talked about River Birch trees of our day.
This beautiful tree shows a lot of promise for the future especially when dealing with global warming. It is available in limited numbers from several large nurseries.
Appreciate the City Slicker® River Birch for its exceptional bark, its resistance to pests, and its tolerance to a warming climate. Also appreciate Carl Whitcomb for his achievements and introductions of better trees for our planet.
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 Specialist, Aerial Lift Specialist, or BCMA 0.25 science and 0.25 practice credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
By Len Phillips
The Tree
Betula nigra 'WhitXXV', PP16573, given the trademark name of City Slicker® Birch, is noted for its heat tolerance, good vigor, and the best drought resistance of all the river birch cultivars. The lustrous, dark green leaves are covered with surface waxes that enhance the drought resistance. The leaves turn a beautiful golden yellow in autumn.
The canopy of Betula nigra 'WhitXXV' will develop an oval form. This tree is said to be unattractive to deer and resistant to borers. It is a low maintenance tree and grows at a medium to fast rate. City Slicker® Birch prefers a moist soil but will tolerate periods of drought. It does well in light shade as well as full sun. Betula nigra ‘WHIT XXV’ has not been observed under all possible environmental conditions yet, but understand that the appearance may vary significantly with variations in soils, temperature, light intensity, and length of day, without any differences in the genetics of the tree and will do well throughout most of the U.S.
Male and female flowers appear in separate catkins on the same tree. The male flowers are characterized as hanging clusters of slender, shiny dark brown catkins that are between 1.5 in (4 cm) and 2.5 in (6 cm) long. The female flowers are characterized as being in upright green catkins that are between 0.15 and 0.4 inches (0.4 – 1 cm) long.
The Tales
While exploring botanical archives, Carl Whitcomb learned that during the last ice age, 30 or more species of birch trees were forced to migrate southward but only river birch, Betula nigra, remained in the south as temperatures warmed and the glaciers retreated. For some reason the river birch were the only species that tolerated the heat and avoided being attacked by the bronze birch borer.
Carl was interested in this so in the spring of 1986, he began to explore some of the western most native river birch trees located in central Oklahoma. These trees appeared to have exceptional heat and drought tolerance as they were growing along a narrow stream bed that was dry most of the year. The trees were small in stature with bark slightly lighter than typical river birch. A soil sample from near the trees showed alkaline soil with low nutrient levels, especially phosphorus, iron and manganese.
Seeds were collected in the spring of 1986, but none germinated. The process was repeated in 1987 and approximately three pounds of seeds were gathered (there are about 375,000 seeds per pound). From this seed lot, only a small fraction of the seeds germinated and most were weak and did not survive the first summer. There were, however three vigorous seedlings that were planted into a field and allowed to grow. Of these three seedlings, two were loose and open branched trees typical of the species and of little interest. The other seedling was more ornamental with denser branching, darker leaves and slightly slower growing. When this unusual seedling was six years old, seeds were produced and all were collected and planted. Many seedlings were weak and did not survive but about 600 seedlings were judged to have acceptable vigor and were planted in the field and allowed to grow. After five years, the seedling with the lightest bark produced viable seed which were collected and planted. Only 67 plants resulted, but one of the fourth generation seedlings had distinctly dark green leaves on dense branches well distributed around the main stems and when a stem reached about ¾ to 1 inch (2-3 cm) in diameter it began to peel. The inner bark was white. Today this seedling is nearly ten inches in diameter at the base and the bark remains white during fall and winter (it is necessary for light to contact the bark to shift to the white color). This unique seedling was given the cultivar name ‘Whit XXV’ and the registered trademark name City Slicker®. The USA Plant Patent #16573 has been awarded to this tree.
Cuttings from City Slicker® birch do produce roots and grow with vigor both in containers and in the field. Little effort is required to form an attractive multiple stem tree. Propagation procedures by tissue culture have been worked out and liners are available. Two trees were planted at a site in Fort Atkinson, Wisconsin in 2002 and survived a January 2019 temperature of -21° F (-30°C) with no winter damage. Under Oklahoma conditions City Slicker® is more heat and drought tolerant than Heritage® or Dura-Heat® cultivars and many other trees. Leaves of City Slicker® are smaller and darker green than Heritage, but slightly larger than Dura-Heat under the same conditions.
During the severe summer drought of 2011, the greater drought tolerance of City Slicker® was distinct. City Slicker® appears to have a range of adaptation from hardiness zones 5 (but most likely 4) through 9 and growth estimates are that it will reach a maximum height in the 30 to 40 foot (9–12 m) range with a 20 to 25 foot (6–8 m) spread. City Slicker® is one of the most talked about River Birch trees of our day.
This beautiful tree shows a lot of promise for the future especially when dealing with global warming. It is available in limited numbers from several large nurseries.
Appreciate the City Slicker® River Birch for its exceptional bark, its resistance to pests, and its tolerance to a warming climate. Also appreciate Carl Whitcomb for his achievements and introductions of better trees for our planet.
Sources
- J. Frank Schmidt & Son Nursery photo
- Personal communications with Carl Whitcomb.
- U.S. Patent application for Betula nigra 'WhitXXV', PP16573
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 Specialist, Aerial Lift Specialist, or BCMA 0.25 science and 0.25 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.
The Flemer Family of Nurserymen
By William Flemer IV
The original family business, F&F Nurseries was founded in 1913 by William Flemer Sr., and was located in Springfield, New Jersey. In the 1920's, when it became Princeton Nurseries, it had grown to become a large commercial plant nursery and had relocated to Kingston, New Jersey. The Kingston location was halfway between New York City and Philadelphia and on a branch of the Pennsylvania Railroad. It was also along the D&R Canal giving the location great logistical advantages.
William Flemer Jr. (Bill) entertained himself during World War I thinking about what he'd like to do with the nursery when he got home from serving in Europe. He began with the office building being constructed in 1920 in the style of a Bavarian hunting lodge, with cobblestone walls, diamond-mullioned windows, a big fireplace in a two-story room, and a stag's head mounted on the wall. There was a small blacksmith shop by the office. A mechanic and a shop was dedicated to the fleet of vehicles. There were two side by side boilers, fired first by coal, and later by oil, with tanks to store a year's worth of fuel oil, bought at low prices in summer.
Bill may have had a vision of Princeton Nurseries as a kind of feudal empire, largely self-sufficient, and with everyone living right there. Little by little, he bought up adjoining farms. He was especially keen on buying properties with houses, and ultimately owned about 45 houses, most painted colonial yellow, a color he liked.
Also near the office building was a well that was the source of water for the whole property. Bill then built a water tower and organized the Kingston Water Company, which supplied water to the entire town for many years, at an annual cost to each household of about $8 a year. Eventually (with a sigh of relief) John Flemer sold all the water rights to Elizabethtown Water Company, except in the nursery.
Trees, shrubs, and other plants were shipped by truck or from the railroad siding behind the packing shed. In addition, barges on the D&R canal near the packing shed also carried many trees to customers. When Bill was most active in the family business, about 75 year-round foreman and laborers were employed, and eight to ten people worked in administration. Princeton Nurseries depended on a force of 60 to 80 Puerto Rican contract workers to work from March to December. They had free transportation and housing, a win-win situation for both parties. Many ultimately decided to stay permanently, and brought their families to live at the nursery.
In 1922, Princeton American Elm was selected by Bill as a tree that represented the classic American Elm, with a dense symmetrical upright vase-shape and large, leathery, dark green leaves that change to yellow in autumn. Ten years after Princeton Elm was introduced in New Jersey, it was discovered that this tree was also resistant to Dutch elm disease (DED). Besides resistance to DED the Princeton elm also demonstrated a resistance to damage from elm beetles. This elm is not a hybrid but a true American elm selection with a proven record of DED resistance and longevity as a classic American street tree. However, while seedlings from this tree are susceptible to DED, cuttings from the original Princeton American Elm are resistant. Arborists should be aware of this when purchasing Princeton American Elms.
The nursery business was very profitable in the years before the Depression and it struggled back to profitability soon after World War II. Production of a lot of fruits and vegetables helped the company make it through the war years. Some of Princeton Nurseries' biggest sellers were evergreens and fruit trees in William Flemer Jr.'s time. Later, the Shademaster Honeylocust (a thornless tree that was a good replacement for elms hit by Dutch elm disease), and the October Glory Red Maple became very popular shade trees.
Bare-root production took off in the 1950's, and was facilitated by Bill's invention of a raised Caterpillar digging machine that has since become a standard in the industry. Another one of Bill's innovations was the use of mesh baskets in which B&B plants could be nested, driven through the overhead doors of the building, and then lifted from the truck by overhead cranes. The taller storage buildings were used for balled and burlapped stock, which were kept on pallets and watered as necessary. They could also be stored temporarily in racks until it was time for them to be shipped or graded.
Many low, Dutch-style greenhouses were used for rooting cuttings in sand and had vents for heat escape. When ready, the cuttings were put in pots and placed in the sash houses. The sash houses had removable sash, to be used as open environments in summer. Seedlings were grown in a miniature nursery, kind of independent from the main operation. The area for this function features wonderful native sandy soil, and has been the source of many Indian artifacts.
In the 1960's, container production was added. The original pots were steel-recycled tomato and clam cans which soon gave way to the lighter and easier to handle polyethylene containers. The big challenge was how to load mixed shipments of bare-root, B&B, and container stock to arrive at the customer's place in satisfactory condition.
William Flemer III and his brother John built up the company to its heyday in the 1970's and 1980's. William III worked to improve varieties of all the major shade trees, one example being the Princeton Sentry ginkgo, a male with columnar form. His talent was recognizing and selecting the best trees among vast populations of seedling trees. He had an eye for spotting vigorous growth, fast and straight form, and late leafing out for a longer digging season. He can also claim credit for the Snow Queen Oak Leaf Hydrangea, although his affinity was for shade and flowering trees.
William Flemer III filed for 22 patents to protect his inventions of trees and shrubs. The more popular trees include:
Zelkova serrata "Village Green”
Sophora japonica “Regent”
Prunus yedoensis "Akebono"
Malus "Bridal Bouquet"
Acer platanoides “Princeton Gold"
Amelanchier candensis "White Pillar"
Malus hupehensis “Cardinal''
Amelanchier laevis "Majestic"
Acer palmatum "Crimson Prince"
Robinia “Purple Crown”
Much of the recent business has become bare-root production because it is very efficient, once the initial investment is made. Deciduous trees and shrubs are harvested after losing their leaves. The dirt is shaken from the roots and they are kept in cool storage (35 to 40 degrees, ideally) and moist until spring shipping time. The storage buildings are insulated, but not refrigerated.
The nursery has also developed a soil mix for growing their products. Composted leaves, which are available in abundance, are shredded and combined with the local sand and this is what is used as potting soil.
By 1995, the nursery had grown to become the largest commercial nursery in the United States.
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, 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 William Flemer IV
The original family business, F&F Nurseries was founded in 1913 by William Flemer Sr., and was located in Springfield, New Jersey. In the 1920's, when it became Princeton Nurseries, it had grown to become a large commercial plant nursery and had relocated to Kingston, New Jersey. The Kingston location was halfway between New York City and Philadelphia and on a branch of the Pennsylvania Railroad. It was also along the D&R Canal giving the location great logistical advantages.
William Flemer Jr. (Bill) entertained himself during World War I thinking about what he'd like to do with the nursery when he got home from serving in Europe. He began with the office building being constructed in 1920 in the style of a Bavarian hunting lodge, with cobblestone walls, diamond-mullioned windows, a big fireplace in a two-story room, and a stag's head mounted on the wall. There was a small blacksmith shop by the office. A mechanic and a shop was dedicated to the fleet of vehicles. There were two side by side boilers, fired first by coal, and later by oil, with tanks to store a year's worth of fuel oil, bought at low prices in summer.
Bill may have had a vision of Princeton Nurseries as a kind of feudal empire, largely self-sufficient, and with everyone living right there. Little by little, he bought up adjoining farms. He was especially keen on buying properties with houses, and ultimately owned about 45 houses, most painted colonial yellow, a color he liked.
Also near the office building was a well that was the source of water for the whole property. Bill then built a water tower and organized the Kingston Water Company, which supplied water to the entire town for many years, at an annual cost to each household of about $8 a year. Eventually (with a sigh of relief) John Flemer sold all the water rights to Elizabethtown Water Company, except in the nursery.
Trees, shrubs, and other plants were shipped by truck or from the railroad siding behind the packing shed. In addition, barges on the D&R canal near the packing shed also carried many trees to customers. When Bill was most active in the family business, about 75 year-round foreman and laborers were employed, and eight to ten people worked in administration. Princeton Nurseries depended on a force of 60 to 80 Puerto Rican contract workers to work from March to December. They had free transportation and housing, a win-win situation for both parties. Many ultimately decided to stay permanently, and brought their families to live at the nursery.
In 1922, Princeton American Elm was selected by Bill as a tree that represented the classic American Elm, with a dense symmetrical upright vase-shape and large, leathery, dark green leaves that change to yellow in autumn. Ten years after Princeton Elm was introduced in New Jersey, it was discovered that this tree was also resistant to Dutch elm disease (DED). Besides resistance to DED the Princeton elm also demonstrated a resistance to damage from elm beetles. This elm is not a hybrid but a true American elm selection with a proven record of DED resistance and longevity as a classic American street tree. However, while seedlings from this tree are susceptible to DED, cuttings from the original Princeton American Elm are resistant. Arborists should be aware of this when purchasing Princeton American Elms.
The nursery business was very profitable in the years before the Depression and it struggled back to profitability soon after World War II. Production of a lot of fruits and vegetables helped the company make it through the war years. Some of Princeton Nurseries' biggest sellers were evergreens and fruit trees in William Flemer Jr.'s time. Later, the Shademaster Honeylocust (a thornless tree that was a good replacement for elms hit by Dutch elm disease), and the October Glory Red Maple became very popular shade trees.
Bare-root production took off in the 1950's, and was facilitated by Bill's invention of a raised Caterpillar digging machine that has since become a standard in the industry. Another one of Bill's innovations was the use of mesh baskets in which B&B plants could be nested, driven through the overhead doors of the building, and then lifted from the truck by overhead cranes. The taller storage buildings were used for balled and burlapped stock, which were kept on pallets and watered as necessary. They could also be stored temporarily in racks until it was time for them to be shipped or graded.
Many low, Dutch-style greenhouses were used for rooting cuttings in sand and had vents for heat escape. When ready, the cuttings were put in pots and placed in the sash houses. The sash houses had removable sash, to be used as open environments in summer. Seedlings were grown in a miniature nursery, kind of independent from the main operation. The area for this function features wonderful native sandy soil, and has been the source of many Indian artifacts.
In the 1960's, container production was added. The original pots were steel-recycled tomato and clam cans which soon gave way to the lighter and easier to handle polyethylene containers. The big challenge was how to load mixed shipments of bare-root, B&B, and container stock to arrive at the customer's place in satisfactory condition.
William Flemer III and his brother John built up the company to its heyday in the 1970's and 1980's. William III worked to improve varieties of all the major shade trees, one example being the Princeton Sentry ginkgo, a male with columnar form. His talent was recognizing and selecting the best trees among vast populations of seedling trees. He had an eye for spotting vigorous growth, fast and straight form, and late leafing out for a longer digging season. He can also claim credit for the Snow Queen Oak Leaf Hydrangea, although his affinity was for shade and flowering trees.
William Flemer III filed for 22 patents to protect his inventions of trees and shrubs. The more popular trees include:
Zelkova serrata "Village Green”
Sophora japonica “Regent”
Prunus yedoensis "Akebono"
Malus "Bridal Bouquet"
Acer platanoides “Princeton Gold"
Amelanchier candensis "White Pillar"
Malus hupehensis “Cardinal''
Amelanchier laevis "Majestic"
Acer palmatum "Crimson Prince"
Robinia “Purple Crown”
Much of the recent business has become bare-root production because it is very efficient, once the initial investment is made. Deciduous trees and shrubs are harvested after losing their leaves. The dirt is shaken from the roots and they are kept in cool storage (35 to 40 degrees, ideally) and moist until spring shipping time. The storage buildings are insulated, but not refrigerated.
The nursery has also developed a soil mix for growing their products. Composted leaves, which are available in abundance, are shredded and combined with the local sand and this is what is used as potting soil.
By 1995, the nursery had grown to become the largest commercial nursery in the United States.
Sources
- Friends of Princeton Nursery Lands, “History”, April 30, 2019
- “HRI Honoree William Flemer III”, IPPS News, 1 January 2014.
- “Talk By William Flemer IV”, Kingston Greenways, 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, 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.
Big Trees
Edited by Len Phillips
What makes some trees grow tall and others do not? Why are the leaves on the tallest trees all about the same size, and why are those tall trees not even taller? It all has to do with basic scientific principles at work in nature. The explanation is in the physics of the tree’s vascular system that nourishes the tree from leaf, to trunk, to roots and its ability to hoist water hundreds of feet into the air. How does the maximum tree height vary with the environment and what limits the height of trees?
Genetics
Genetics plays an important role in determining tree size. This fact is obvious. Each species and cultivar of species has a very narrow range of sizes. However, what causes one tree out of a group of the same species to grow taller than the others is the focus of this article. Often it is variations caused by genetics, but more likely it is caused by leaf size and climate.
Leaf Size
Researchers found that leaves among all trees vary in size between one inch (2.5 cm) and four feet (125 cm), and as much as one inch within a single species or cultivar. All the tallest species of trees, however, have leaves that fall in the range of 4 to 8 inches (10 – 20 cm) long.
This is because like most plants, trees fuel their growth and development through photosynthesis. This process uses water, carbon dioxide, minerals, and sunlight energy to produce carbohydrates as a sugar-rich fluid. There is an advantage for a tree to have larger leaves. It can produce more of this sugar-rich fluid that will flow quickly toward the trunk and roots via the phloem system. The faster and more efficiently it flows, the larger the tree can grow. If the tree’s leaves are small, the fluid moves too slowly to be beneficial for a tree to have exceptional growth. As the sugar-rich fluid passes through the leaf phloem toward the stem, it gathers speed as more and more water is pulled in from the leaf through osmosis. Consequently, the longer the leaf, the faster the fluid flows.
When the fluid reaches the tree trunk, however, no more sugar is collected in the phloem, and only water is drawn in from the surrounding tissue. The trunk phloem is longer and consequently, presents more resistance to the fluid’s flow as it travels down the trunk to the roots.
Tree Height
We do know that the fastest growing tree in a forest is able to capture more sunlight and also more energy through photosynthesis and can out-grow neighboring trees with less exposure to sunlight. Although increased height might provide some trees with better access to sunlight, it also will increase the length and thus flow resistance of the trunk phloem, slowing the movement of nutrients toward the roots. So there comes a point where the optimal limits on leaf size and tree height intersect, indicating the point at which it is no longer advantageous for the tree to become taller or produce larger leaves. This point is slightly more than 300 feet (100 meters), about the size of the highest existing tall trees.
Other Factors
Other factors also play a role in determining tree height such as soil fertility, the frequency of wildfires, and the length of the growing season. However, these factors have only a minor influence on tree growth.
Climate
How does the maximum tree height vary with the environment? Does the photosynthetic energy that trees devote to produce new leaves alter the ability to hoist water hundreds of feet up the trunk of the tree? A recent study determined that tree height, resource allocation, and physiology vary with climate, so climate is also likely to be the reason trees grow as high as they do.
The tallest of the flowering trees on record is a Eucalyptus regnans, mountain ash, which has grown to 374 feet (114 m) tall, and it is found in southern Australia. Sequoia sempervirens, the coastal redwood or California redwood is the tallest living evergreen in the world with one at over 379 feet (115.5 m) tall. It is found in northern California. The climate in both locations is similar with high rainfall, high humidity, and low evaporation rates. The tallest and oldest trees are found in deep valleys and gullies, where year-round streams can flow, and fog drip is a regular occurrence. Cool coastal air and fog drip keep these forests consistently damp year round and the trees do not suffer from evaporation stress. The trees above the fog layer are shorter and smaller due to the drier, windier, and colder climate. The moisture supply is obviously very important in growing extremely tall trees.
Researchers found a relationship between maximum tree height and the ratio of annual rainfall to evaporation. As the ratio increased, so did the maximum tree height. One explanation for this is that the constant supply of soil water allows the trees to allocate fewer resources to growing roots in search of water. Another factor deals with the high humidity that increases the rate of photosynthesis. This causes the stomata to open and take in more carbon dioxide that encourages greater growth by building more wood.
To summarize all this information, among a single species, the tree with the largest leaves and full access to water in the soil and humid air, will grow the tallest.
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, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Edited by Len Phillips
What makes some trees grow tall and others do not? Why are the leaves on the tallest trees all about the same size, and why are those tall trees not even taller? It all has to do with basic scientific principles at work in nature. The explanation is in the physics of the tree’s vascular system that nourishes the tree from leaf, to trunk, to roots and its ability to hoist water hundreds of feet into the air. How does the maximum tree height vary with the environment and what limits the height of trees?
Genetics
Genetics plays an important role in determining tree size. This fact is obvious. Each species and cultivar of species has a very narrow range of sizes. However, what causes one tree out of a group of the same species to grow taller than the others is the focus of this article. Often it is variations caused by genetics, but more likely it is caused by leaf size and climate.
Leaf Size
Researchers found that leaves among all trees vary in size between one inch (2.5 cm) and four feet (125 cm), and as much as one inch within a single species or cultivar. All the tallest species of trees, however, have leaves that fall in the range of 4 to 8 inches (10 – 20 cm) long.
This is because like most plants, trees fuel their growth and development through photosynthesis. This process uses water, carbon dioxide, minerals, and sunlight energy to produce carbohydrates as a sugar-rich fluid. There is an advantage for a tree to have larger leaves. It can produce more of this sugar-rich fluid that will flow quickly toward the trunk and roots via the phloem system. The faster and more efficiently it flows, the larger the tree can grow. If the tree’s leaves are small, the fluid moves too slowly to be beneficial for a tree to have exceptional growth. As the sugar-rich fluid passes through the leaf phloem toward the stem, it gathers speed as more and more water is pulled in from the leaf through osmosis. Consequently, the longer the leaf, the faster the fluid flows.
When the fluid reaches the tree trunk, however, no more sugar is collected in the phloem, and only water is drawn in from the surrounding tissue. The trunk phloem is longer and consequently, presents more resistance to the fluid’s flow as it travels down the trunk to the roots.
Tree Height
We do know that the fastest growing tree in a forest is able to capture more sunlight and also more energy through photosynthesis and can out-grow neighboring trees with less exposure to sunlight. Although increased height might provide some trees with better access to sunlight, it also will increase the length and thus flow resistance of the trunk phloem, slowing the movement of nutrients toward the roots. So there comes a point where the optimal limits on leaf size and tree height intersect, indicating the point at which it is no longer advantageous for the tree to become taller or produce larger leaves. This point is slightly more than 300 feet (100 meters), about the size of the highest existing tall trees.
Other Factors
Other factors also play a role in determining tree height such as soil fertility, the frequency of wildfires, and the length of the growing season. However, these factors have only a minor influence on tree growth.
Climate
How does the maximum tree height vary with the environment? Does the photosynthetic energy that trees devote to produce new leaves alter the ability to hoist water hundreds of feet up the trunk of the tree? A recent study determined that tree height, resource allocation, and physiology vary with climate, so climate is also likely to be the reason trees grow as high as they do.
The tallest of the flowering trees on record is a Eucalyptus regnans, mountain ash, which has grown to 374 feet (114 m) tall, and it is found in southern Australia. Sequoia sempervirens, the coastal redwood or California redwood is the tallest living evergreen in the world with one at over 379 feet (115.5 m) tall. It is found in northern California. The climate in both locations is similar with high rainfall, high humidity, and low evaporation rates. The tallest and oldest trees are found in deep valleys and gullies, where year-round streams can flow, and fog drip is a regular occurrence. Cool coastal air and fog drip keep these forests consistently damp year round and the trees do not suffer from evaporation stress. The trees above the fog layer are shorter and smaller due to the drier, windier, and colder climate. The moisture supply is obviously very important in growing extremely tall trees.
Researchers found a relationship between maximum tree height and the ratio of annual rainfall to evaporation. As the ratio increased, so did the maximum tree height. One explanation for this is that the constant supply of soil water allows the trees to allocate fewer resources to growing roots in search of water. Another factor deals with the high humidity that increases the rate of photosynthesis. This causes the stomata to open and take in more carbon dioxide that encourages greater growth by building more wood.
To summarize all this information, among a single species, the tree with the largest leaves and full access to water in the soil and humid air, will grow the tallest.
Sources
- Maciej Zwieniecki, “Tree Physics”, UC Davis News and Information, January 11, 2013.
- Givnish, Thomas, “New Analysis Links Tree Height to Climate”, University of Wisconsin-Madison, Ecology, 2014.
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, 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.
Toronto
The City with a Future
By Len Phillips
One mile east of downtown, Toronto, Ontario, the city is in the process of building a major new development effort that is focused on building a city for the future. The location is on 750 acres (340 hectares) of waterfront property near the heart of the city. The property is a large vacant industrial area known as the Port Lands and it extends on filled soil, out into Lake Ontario.
Before we look at this large project, let's see how the city got to this point. One of the first recent redevelopment projects conducted by the city of Toronto to improve the waterfront was described in this former Seminars article. The article discussed several small projects such as some new parks, promenades, and of course a lot of tree plantings using soil cells to encourage optimum tree growth. The city was beginning to make improvements to their downtown and waterfront areas in an attempt to revitalize these areas into tourist attractions.
As a result of this successful effort, 'Waterfront Toronto', a quasi-government authority, was established to eventually redevelop the entire Toronto waterfront. Two years ago, Waterfront Toronto redeveloped a 12 acre (5 hectars) parcel of property that included the Jack Layton Ferry Terminal that improved the local ferry service as well as the development of a beautiful waterfront park and the planting of several new trees.
So now that Waterfront Toronto has completed some very successful beautification projects, it is time to move on to a very large project – the Port Lands. Not only is the project a large area, the emphasis has been placed on technology. For this reason, the city is designing a “smart city” to emphasize innovation and technology.
In October 2017, Waterfront Toronto announced the winner of the project design and construction competition to be Sidewalk Labs, a sister company of Google. According to the agreement, Sidewalk Labs would invest $50 million in creating a plan and development of a planned neighborhood for the smart city area to be renamed “Quayside”.
Quayside is scheduled to become a technological wonderland with a mix of 50 percent retail and 40 percent below-market rate housing, which would include a minimum of 20 percent affordable housing, making sure that this community reflects the full diversity of Toronto. The area will be home to new business, residential buildings and public space, including lots of trees. The area will be dubbed as green by encouraging the use of electric vehicles and an onsite power generation station using renewable energy.
The plan envisions the neighborhood being built entirely of mass timber, a material that the company anticipates would cut the costs of construction by 15 percent. Although this form of construction is becoming more common around the world, the company claims that Quayside would represent the largest-scale use of mass timber yet. At least some buildings would be factory-constructed, which is another approach to reduced-cost building that has become a rallying point among affordable housing advocates around North America.
On the environmental front, the company envisions moving towards a “climate positive” footprint by reducing emissions in the neighborhood by 75 to 80 percent. This would be achieved through a combination of green building standards, solar power generation and geothermal heating, energy monitoring systems, and a streamlined waste and water management system, as well as the planting of hundreds of trees.
The eco-friendly timber high-rise buildings will be elegant, airy, green, and inexpensive modular units. Underground will be tunnels that will allow the delivery of packages by robots. The robot would also haul away waste that will be processed and reused. Above ground, autonomous vehicles would ferry residents around, thus removing the need for parking spaces. Solar power would light the neighborhood while fresh air off the chilly waters of Lake Ontario would cool the buildings in summer. Removable pavers will make street repair easy. There will also be sensors everywhere sorting the flow of people, bicycles, and driver-less cars. Some sensors will also indicate when trash bins need to be emptied and other sensors will be calibrating building light and temperature settings allowing the physical environment to interact with visitors and residents.
Toronto is one of the fastest growing big cities in North America. Canada's open immigration policies account for much of this growth. It is far easier for well-off, skilled people to immigrate to Canada than to the United States. Most of these new residents make their home in or around Toronto, so the city of 6 million people is growing very rapidly. This growth and the shortage of housing is prompting Quayside to begin construction as soon as possible.
And of course, there will be lots and lots of new trees being planted in soil cells. But not just any trees. They will be looking for disease resistant, drought and heat tolerant trees that will survive long into the future. The trees must also be low maintenance, but high in seasonal beauty.
Construction has already started on some parts of Quayside, so get your name on the list if you are planning to move.
Sources:
The test that follows contains 10 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
ISA will award .5 CEUs* for a passing grade. SAF members will earn 0.5 Cat. 1-CF for every five passing test scores. The cost for taking this test is $10. If you purchase an annual subscription for 15 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report all passing test scores to ISA and/or SAF. If you are a member of ISA and SAF we will report your passing test scores to both for no additional cost. Please be sure to add both of your certification numbers when you sign in. Tests with passing scores may be submitted only once to each organization.
*Members of ISA may apply the 0.5 CEUs toward Certified Arborist, Municipal Specialist, or BCMA 0.25 science and 0.25 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.
The City with a Future
By Len Phillips
One mile east of downtown, Toronto, Ontario, the city is in the process of building a major new development effort that is focused on building a city for the future. The location is on 750 acres (340 hectares) of waterfront property near the heart of the city. The property is a large vacant industrial area known as the Port Lands and it extends on filled soil, out into Lake Ontario.
Before we look at this large project, let's see how the city got to this point. One of the first recent redevelopment projects conducted by the city of Toronto to improve the waterfront was described in this former Seminars article. The article discussed several small projects such as some new parks, promenades, and of course a lot of tree plantings using soil cells to encourage optimum tree growth. The city was beginning to make improvements to their downtown and waterfront areas in an attempt to revitalize these areas into tourist attractions.
As a result of this successful effort, 'Waterfront Toronto', a quasi-government authority, was established to eventually redevelop the entire Toronto waterfront. Two years ago, Waterfront Toronto redeveloped a 12 acre (5 hectars) parcel of property that included the Jack Layton Ferry Terminal that improved the local ferry service as well as the development of a beautiful waterfront park and the planting of several new trees.
So now that Waterfront Toronto has completed some very successful beautification projects, it is time to move on to a very large project – the Port Lands. Not only is the project a large area, the emphasis has been placed on technology. For this reason, the city is designing a “smart city” to emphasize innovation and technology.
In October 2017, Waterfront Toronto announced the winner of the project design and construction competition to be Sidewalk Labs, a sister company of Google. According to the agreement, Sidewalk Labs would invest $50 million in creating a plan and development of a planned neighborhood for the smart city area to be renamed “Quayside”.
Quayside is scheduled to become a technological wonderland with a mix of 50 percent retail and 40 percent below-market rate housing, which would include a minimum of 20 percent affordable housing, making sure that this community reflects the full diversity of Toronto. The area will be home to new business, residential buildings and public space, including lots of trees. The area will be dubbed as green by encouraging the use of electric vehicles and an onsite power generation station using renewable energy.
The plan envisions the neighborhood being built entirely of mass timber, a material that the company anticipates would cut the costs of construction by 15 percent. Although this form of construction is becoming more common around the world, the company claims that Quayside would represent the largest-scale use of mass timber yet. At least some buildings would be factory-constructed, which is another approach to reduced-cost building that has become a rallying point among affordable housing advocates around North America.
On the environmental front, the company envisions moving towards a “climate positive” footprint by reducing emissions in the neighborhood by 75 to 80 percent. This would be achieved through a combination of green building standards, solar power generation and geothermal heating, energy monitoring systems, and a streamlined waste and water management system, as well as the planting of hundreds of trees.
The eco-friendly timber high-rise buildings will be elegant, airy, green, and inexpensive modular units. Underground will be tunnels that will allow the delivery of packages by robots. The robot would also haul away waste that will be processed and reused. Above ground, autonomous vehicles would ferry residents around, thus removing the need for parking spaces. Solar power would light the neighborhood while fresh air off the chilly waters of Lake Ontario would cool the buildings in summer. Removable pavers will make street repair easy. There will also be sensors everywhere sorting the flow of people, bicycles, and driver-less cars. Some sensors will also indicate when trash bins need to be emptied and other sensors will be calibrating building light and temperature settings allowing the physical environment to interact with visitors and residents.
Toronto is one of the fastest growing big cities in North America. Canada's open immigration policies account for much of this growth. It is far easier for well-off, skilled people to immigrate to Canada than to the United States. Most of these new residents make their home in or around Toronto, so the city of 6 million people is growing very rapidly. This growth and the shortage of housing is prompting Quayside to begin construction as soon as possible.
And of course, there will be lots and lots of new trees being planted in soil cells. But not just any trees. They will be looking for disease resistant, drought and heat tolerant trees that will survive long into the future. The trees must also be low maintenance, but high in seasonal beauty.
Construction has already started on some parts of Quayside, so get your name on the list if you are planning to move.
Sources:
- Bliss, Laura, “Sidewalk Labs’ Neighborhood of the Future in Toronto Is Getting Closer”, Nov 30, 2018.
- Buntin, John, “Technolopolis”, Governing, July 2019.
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