Seminar #100 from Online Seminars for Municipal Arborists
October - December 2023
In honor of 100 Online Seminars, this Seminar is a celebration of trees that have been selected to tolerate global warming. Do you know ten cultivars of trees that will tolerate global warming? Here are my ten favorite urban tolerant trees and the stories that go with them.
Sections Go directly to the section by clicking on the title below
October - December 2023
In honor of 100 Online Seminars, this Seminar is a celebration of trees that have been selected to tolerate global warming. Do you know ten cultivars of trees that will tolerate global warming? Here are my ten favorite urban tolerant trees and the stories that go with them.
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.
Powder Keg® Maple
by Len Phillips
The Tree
Acer saccharum 'Whit XLIX' Plant Patent – PP#23,957, has been given the registered trademark name Powder Keg®. This maple is a fast-growing Caddo sugar maple with a more upright shape than typical of other sugar maples. What makes this tree special is its dark leathery leaves that do not tatter, and its strong growth, straight trunk, oval canopy shape, and its tolerance to the coming of global warming with heat and drought.
Caddo sugar maples are remnant trees growing in the deep canyons of SW Oklahoma, especially Caddo County and the TX panhandle. With the last ice age, trees moved south, then when the ice retreated, these sugar maples continued to grow in the debris accumulated at the base of canyon walls. Over the years the trees have adapted to be more tolerant to heat and drought. DNA testing shows they are the same as Eastern North American sugar maples trees noted for toughness in withstanding heat and drought.
They can grow to 40 – 60 feet (15 m) tall, and 40 feet (12 m) wide. There are no serious insect or disease problems except for minor attacks of verticillium wilt, anthracnose, cankers, and leaf spot. Unlike other sugar maples, Powder Keg® is also immune to problems with aphids, borers, and scale. Leaf scorch may be a problem in drought conditions. This tree is easily grown in average, medium moisture, well – drained sandy or loamy soil. It does best in fertile, slightly acidic, moist soils in full sun to part shade. The preferred hardiness zone is 5 – 9 and the heat zone is 8 to 1. The flowers are in panicles of 5 – 10 together, yellow – green, and without petals. Flowering occurs in early spring, after growing in 30 – 55 degree days. This sugar maple will generally begin flowering when it is between 10 – 15 years old. The fruit is a pair of samaras.
Powder Keg® has deciduous, dark green leaves that are 3 – 6 inches (7 – 15 cm) long and wide with 3 – 5 palmate lobes. The basal lobes are relatively small, while the upper lobes are larger and deeply notched. In autumn, they turn from bright yellow through orange to fluorescent red – orange, sometimes with considerable color variations. This sugar maple is most easily identified by clear sap in the leaf petiole. They look best in the northern and western part of their range.
The Tales
Carl E. Whitcomb, owner of Lacebark Inc. Stillwater, OK tells the story about colleagues who were discussing the grandeur of Caddo sugar maples in their autumn color and their toughness to withstand heat and drought. It could become a great city tree with some research because very few Caddo maple trees produced seeds and those that had been collected season after season, had little or no germination and the few that did germinate ended up as runts with little or no vigor.”
However, 1986 was an exception as the Caddo sugar maple seed population was higher this particular year. Carl collected seed from 14 trees across the state, in hopes that a superior parent could be found. And, indeed, seeds from one tree in Stillwater germinated better and produced a higher number of stronger seedlings than all the others. Seeds collected from this tree in 1994 were especially good, resulting in 28 exceptional seedlings. These were grown first in containers, then in the field for a number of years. But with each year’s evaluation, one to several seedlings would be culled and discarded until only five remained. In all aspects of desirable tree form, dark green foliage color, resistance of leaves to heat, wind and drought, and most spectacularly, autumn color, one tree consistently stood out. This special tree would remain dark green all summer and into very late autumn. Then after nearly all other trees around had lost their leaves, this tree will produce an explosion of color beginning at the top and progressing slowly downward, first as shades of yellow and light orange, then to dark orange and red. Compared to other sugar maples, the spectacular color of Powder Keg® continued for two to three weeks or longer, depending on the season. This spectacular tree earned the registered trademark name of Powder Keg®.
But this is not the end of the story, because sugar maples are notorious for being difficult to propagate, especially from cuttings. After a number of years of taking cuttings and using every trick in the book and beyond, the cuttings would root reasonably well, but would not survive the first winter. Carl preferred to have the tree on its own roots, but after hundreds of rooted cuttings and only one survivor, the idea of budding or grafting Powder Keg® onto some other species seemed worth trying. So, Carl contacted Keith Warren with J. Frank Schmidt Nursery. Keith had been budding a selection of Caddo onto eastern sugar maple seedlings. In late July 2011, the budding of Powder Keg® onto eastern sugar maple seedlings began. In one growing season the buds grew six feet or more and became excellent branched trees ready to be harvested bare root and shipped back to Oklahoma or wherever they were wanted. The combination of a very heat and drought tolerant top that consistently yields spectacular autumn color on a tough eastern sugar maple root system, and is also adaptable to a wide geographic range, was a success. The tree is now in commercial production.
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
by Len Phillips
The Tree
Acer saccharum 'Whit XLIX' Plant Patent – PP#23,957, has been given the registered trademark name Powder Keg®. This maple is a fast-growing Caddo sugar maple with a more upright shape than typical of other sugar maples. What makes this tree special is its dark leathery leaves that do not tatter, and its strong growth, straight trunk, oval canopy shape, and its tolerance to the coming of global warming with heat and drought.
Caddo sugar maples are remnant trees growing in the deep canyons of SW Oklahoma, especially Caddo County and the TX panhandle. With the last ice age, trees moved south, then when the ice retreated, these sugar maples continued to grow in the debris accumulated at the base of canyon walls. Over the years the trees have adapted to be more tolerant to heat and drought. DNA testing shows they are the same as Eastern North American sugar maples trees noted for toughness in withstanding heat and drought.
They can grow to 40 – 60 feet (15 m) tall, and 40 feet (12 m) wide. There are no serious insect or disease problems except for minor attacks of verticillium wilt, anthracnose, cankers, and leaf spot. Unlike other sugar maples, Powder Keg® is also immune to problems with aphids, borers, and scale. Leaf scorch may be a problem in drought conditions. This tree is easily grown in average, medium moisture, well – drained sandy or loamy soil. It does best in fertile, slightly acidic, moist soils in full sun to part shade. The preferred hardiness zone is 5 – 9 and the heat zone is 8 to 1. The flowers are in panicles of 5 – 10 together, yellow – green, and without petals. Flowering occurs in early spring, after growing in 30 – 55 degree days. This sugar maple will generally begin flowering when it is between 10 – 15 years old. The fruit is a pair of samaras.
Powder Keg® has deciduous, dark green leaves that are 3 – 6 inches (7 – 15 cm) long and wide with 3 – 5 palmate lobes. The basal lobes are relatively small, while the upper lobes are larger and deeply notched. In autumn, they turn from bright yellow through orange to fluorescent red – orange, sometimes with considerable color variations. This sugar maple is most easily identified by clear sap in the leaf petiole. They look best in the northern and western part of their range.
The Tales
Carl E. Whitcomb, owner of Lacebark Inc. Stillwater, OK tells the story about colleagues who were discussing the grandeur of Caddo sugar maples in their autumn color and their toughness to withstand heat and drought. It could become a great city tree with some research because very few Caddo maple trees produced seeds and those that had been collected season after season, had little or no germination and the few that did germinate ended up as runts with little or no vigor.”
However, 1986 was an exception as the Caddo sugar maple seed population was higher this particular year. Carl collected seed from 14 trees across the state, in hopes that a superior parent could be found. And, indeed, seeds from one tree in Stillwater germinated better and produced a higher number of stronger seedlings than all the others. Seeds collected from this tree in 1994 were especially good, resulting in 28 exceptional seedlings. These were grown first in containers, then in the field for a number of years. But with each year’s evaluation, one to several seedlings would be culled and discarded until only five remained. In all aspects of desirable tree form, dark green foliage color, resistance of leaves to heat, wind and drought, and most spectacularly, autumn color, one tree consistently stood out. This special tree would remain dark green all summer and into very late autumn. Then after nearly all other trees around had lost their leaves, this tree will produce an explosion of color beginning at the top and progressing slowly downward, first as shades of yellow and light orange, then to dark orange and red. Compared to other sugar maples, the spectacular color of Powder Keg® continued for two to three weeks or longer, depending on the season. This spectacular tree earned the registered trademark name of Powder Keg®.
But this is not the end of the story, because sugar maples are notorious for being difficult to propagate, especially from cuttings. After a number of years of taking cuttings and using every trick in the book and beyond, the cuttings would root reasonably well, but would not survive the first winter. Carl preferred to have the tree on its own roots, but after hundreds of rooted cuttings and only one survivor, the idea of budding or grafting Powder Keg® onto some other species seemed worth trying. So, Carl contacted Keith Warren with J. Frank Schmidt Nursery. Keith had been budding a selection of Caddo onto eastern sugar maple seedlings. In late July 2011, the budding of Powder Keg® onto eastern sugar maple seedlings began. In one growing season the buds grew six feet or more and became excellent branched trees ready to be harvested bare root and shipped back to Oklahoma or wherever they were wanted. The combination of a very heat and drought tolerant top that consistently yields spectacular autumn color on a tough eastern sugar maple root system, and is also adaptable to a wide geographic range, was a success. The tree is now in commercial production.
Sources
- Dirr, Michael A. and Keith S. Warren, “The Tree Book”, Timber Press, 2019.
- J. Frank Schmidt & Son Fact Sheet
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Heritage Birch
by Len Phillips
The Tree
Betula nigra 'Cully', commonly called Heritage Birch is the correct name even though the tree is being sold under the trade name Heritage River Birch. Heritage is a vigorous, fast – growing, medium – sized tree that grows 40 to 70 feet tall (12 to 21 m) and has a 40 to 60 feet (12 to 20 m) wide spread. It can be grown as either a single trunk or multi–stemmed tree and features salmon–cream to brownish bark which exfoliates to reveal a creamy white inner bark that can be nearly as white as the white barked birches. The colorful, peeling bark will also add interest to a winter landscape. The tree tolerates heat and drought once established within Hardiness Zones 4 through 9 and Heat Zones 8 to 1. It prefers acidic and moist soil but will adapt to wet clay soil and will do well throughout most of the U.S. The flowers are greenish in color.
Heritage's green leaves are triangular in shape with toothed edges, and they turn yellow in autumn. The Heritage River Birch is often chosen for its attractive bark and ability to resist disease. Pruning should be done at the end of the growing season in autumn. This is especially important because the bronze birch borer is active during the spring and open pruning wounds are inviting to them. Transplanting for all birches should be done in the spring. Birch trees are very popular landscape trees but they have many problems including insect and disease problems that may cause an early death. Fortunately, Heritage is not bothered by these problems that impact other birches.
The Tales
Along came a man named Earl Cully who found a solution to the problems with insects and disease that attack the birches. Earl was a nurseryman and he developed a friendship with University of Illinois professor Joe McDaniel who shared his knowledge and encouraged Earl to have a sharp eye to “see” and evaluate woody plants, especially trees. (I had the honor of meeting Earl when he was a guest lecturer at one of Joe classes. Joe was one of my professors at the University.)
One day during a trip to St. Louis Earl noticed unusual bark on a tree. It seemed like it was a native river birch (Betula nigra), but Earl was unsure because the lovely white, peeling bark is a characteristic of the paper bark birch (Betula papyrifera) and not the river birch. Cully made two more trips to St. Louis before he found the owner of the tree at home and was able to get permission to take cuttings for propagation. Cully was uncertain of its species, but he thought his discovery was a hybrid of the paper bark and river birches. Finally, after 10 years of intensive research, including five years of evaluation at the Institute of Forest Genetics at Rhinelander, Wisconsin, it was determined that the tree was a river birch, but a genetically superior one. Cully was awarded U.S. Plant Patent #4,409 issued April 24, 1979 for Betula nigra 'Cully'. Soon after came other Cully cultivars. The most noteworthy are: Burgundy Belle® Red Maple PP# 7,222, Heritage® Lacebark Elm PP# 10,846, Heritage® Hybrid Oak PP# 11,431, Moonglow® Magnolia PP# 12,065, Regal Prince® Hybrid Oak PP# 12,673, Prairie Titan™ Kentucky coffeetree, and Debonair® Pond Cypress. All are excellent trees created by Earl right up until his death in May, 2017.
After Betula nigra 'Cully' was introduced to the nursery trade, growers throughout America were given a license to grow and sell it. Several growers are able to produce hundreds of these trees at a time by using tissue culture, in which bits of the plant are grown in sterile test tubes until they are large enough to be transplanted in soil and grown until they reach an appropriate size for sale.
In 2015, the Heritage Birch received the J. Franklin Styer Award for exceptional plants by the Pennsylvania Horticultural Society. Betula nigra 'Cully' was also selected by the Society of Municipal Arborists as its Urban Tree of the Year in 2002 because, it does not have any serious pest issues and very few maintenance concerns while growing along city streets.
I appreciate the Heritage River Birch for its exceptional bark and resistance to diseases that attack birch trees. I also appreciate Earl Cully for his achievements and introductions of better trees for our planet's fight against global warming.
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
by Len Phillips
The Tree
Betula nigra 'Cully', commonly called Heritage Birch is the correct name even though the tree is being sold under the trade name Heritage River Birch. Heritage is a vigorous, fast – growing, medium – sized tree that grows 40 to 70 feet tall (12 to 21 m) and has a 40 to 60 feet (12 to 20 m) wide spread. It can be grown as either a single trunk or multi–stemmed tree and features salmon–cream to brownish bark which exfoliates to reveal a creamy white inner bark that can be nearly as white as the white barked birches. The colorful, peeling bark will also add interest to a winter landscape. The tree tolerates heat and drought once established within Hardiness Zones 4 through 9 and Heat Zones 8 to 1. It prefers acidic and moist soil but will adapt to wet clay soil and will do well throughout most of the U.S. The flowers are greenish in color.
Heritage's green leaves are triangular in shape with toothed edges, and they turn yellow in autumn. The Heritage River Birch is often chosen for its attractive bark and ability to resist disease. Pruning should be done at the end of the growing season in autumn. This is especially important because the bronze birch borer is active during the spring and open pruning wounds are inviting to them. Transplanting for all birches should be done in the spring. Birch trees are very popular landscape trees but they have many problems including insect and disease problems that may cause an early death. Fortunately, Heritage is not bothered by these problems that impact other birches.
The Tales
Along came a man named Earl Cully who found a solution to the problems with insects and disease that attack the birches. Earl was a nurseryman and he developed a friendship with University of Illinois professor Joe McDaniel who shared his knowledge and encouraged Earl to have a sharp eye to “see” and evaluate woody plants, especially trees. (I had the honor of meeting Earl when he was a guest lecturer at one of Joe classes. Joe was one of my professors at the University.)
One day during a trip to St. Louis Earl noticed unusual bark on a tree. It seemed like it was a native river birch (Betula nigra), but Earl was unsure because the lovely white, peeling bark is a characteristic of the paper bark birch (Betula papyrifera) and not the river birch. Cully made two more trips to St. Louis before he found the owner of the tree at home and was able to get permission to take cuttings for propagation. Cully was uncertain of its species, but he thought his discovery was a hybrid of the paper bark and river birches. Finally, after 10 years of intensive research, including five years of evaluation at the Institute of Forest Genetics at Rhinelander, Wisconsin, it was determined that the tree was a river birch, but a genetically superior one. Cully was awarded U.S. Plant Patent #4,409 issued April 24, 1979 for Betula nigra 'Cully'. Soon after came other Cully cultivars. The most noteworthy are: Burgundy Belle® Red Maple PP# 7,222, Heritage® Lacebark Elm PP# 10,846, Heritage® Hybrid Oak PP# 11,431, Moonglow® Magnolia PP# 12,065, Regal Prince® Hybrid Oak PP# 12,673, Prairie Titan™ Kentucky coffeetree, and Debonair® Pond Cypress. All are excellent trees created by Earl right up until his death in May, 2017.
After Betula nigra 'Cully' was introduced to the nursery trade, growers throughout America were given a license to grow and sell it. Several growers are able to produce hundreds of these trees at a time by using tissue culture, in which bits of the plant are grown in sterile test tubes until they are large enough to be transplanted in soil and grown until they reach an appropriate size for sale.
In 2015, the Heritage Birch received the J. Franklin Styer Award for exceptional plants by the Pennsylvania Horticultural Society. Betula nigra 'Cully' was also selected by the Society of Municipal Arborists as its Urban Tree of the Year in 2002 because, it does not have any serious pest issues and very few maintenance concerns while growing along city streets.
I appreciate the Heritage River Birch for its exceptional bark and resistance to diseases that attack birch trees. I also appreciate Earl Cully for his achievements and introductions of better trees for our planet's fight against global warming.
Sources
- Kozelka, Art,”A Tough Beauty, Heritage Birch Finds Favor”, Chicago Tribune, February 16, 1992.
- Missouri Botanical Garden, Betula nigra 'Cully', Plant Finder
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Kentucky Yellowwood
by Len Phillips
The Tree
Cladrastis kentukea, commonly known as the Kentucky yellowwood, American yellowwood, Virgilia, and yellowwood, is a species of Cladrastis native to the Southeastern United States. Yellowwood grows in an area from western North Carolina west to eastern Oklahoma, and from southern Missouri and Indiana south to central Alabama. The species was formerly called Cladrastis lutea.
Yellowwood's intensely fragrant, wisteria–like, white flowers are in large, drooping, terminal panicles 10” – 15” (25 – 40 cm) long and they will completely cover a mature tree in late spring. Profuse bloom may occur only once every 2 or 3 years. New trees may not bloom for the first 8 – 10 years. Flowers give way to flat seed pods 2.5” – 4” (6.5 – 10 cm) long that mature in September and October.
Easily grown in average, medium moisture, well–drained soils in full sun. It is best sited in a location protected from strong winds.
Cladrastis kentukea is a medium – sized, deciduous tree of the legume family that typically grows 30 feet – 50 feet tall with upright branching and a broad, rounded crown. It is noted for its pinnately compound foliage that forms a canopy of shimmering yellowish green leaves that become bright yellow in autumn.
The Tales
Genus name comes from the Greek klados, meaning branch, and thraustos, meaning fragile for the brittle twigs. The wood of this tree contains a yellow dye that distinctively colors the heartwood and gives rise to the common name of yellowwood. The yellowwood is used in small amounts for specialist furniture, gun stocks and decorative wood turning.
Cladrastis kentukea is an excellent small tree for residential lawns, particularly on smaller properties. Also may be planted near patios and terraces. They may be effectively grouped on larger properties. Roots go deep, so other plants may be easily grown underneath the branches. Yellowwood has no serious insect or disease problems. This tree tolerates dry soils once it is established. However, Yellowwood State Forest in southern Indiana has almost no Yellowwood trees growing there because of the dry soil.
Cladrastis kentukea won a Pennsylvania Horticultural Society Gold Award in 1994. Yellowwood was also selected as the 2015 Urban Tree of the Year by a vote from the members of the Society of Municipal Arborists. This tree's popularity comes from the tree's many unique features including its ability to tolerate the urban environment.
Cladrastis kentukea is one of the rarest native trees of eastern North America. It is found principally on the limestone cliffs of Kentucky, Tennessee and North Carolina. However, today the tree is being installed in locations all over the country in Zones 4 to 8. Pruning should occur in summer because cuts made in late winter or spring tend to bleed.
The Champion Yellowwood is growing at Spring Grove Cemetery in Cincinnati, Ohio. It is 75 feet (22 m) tall and has a 7 feet 4 inches. (2.2 m) trunk diameter. The tallest known Yellowwood is a slender forest tree 90 ft. (27 m) tall but only 2 ft. (0.55 m) in trunk diameter, at Plott Cove Research Natural Area in Georgia.
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
by Len Phillips
The Tree
Cladrastis kentukea, commonly known as the Kentucky yellowwood, American yellowwood, Virgilia, and yellowwood, is a species of Cladrastis native to the Southeastern United States. Yellowwood grows in an area from western North Carolina west to eastern Oklahoma, and from southern Missouri and Indiana south to central Alabama. The species was formerly called Cladrastis lutea.
Yellowwood's intensely fragrant, wisteria–like, white flowers are in large, drooping, terminal panicles 10” – 15” (25 – 40 cm) long and they will completely cover a mature tree in late spring. Profuse bloom may occur only once every 2 or 3 years. New trees may not bloom for the first 8 – 10 years. Flowers give way to flat seed pods 2.5” – 4” (6.5 – 10 cm) long that mature in September and October.
Easily grown in average, medium moisture, well–drained soils in full sun. It is best sited in a location protected from strong winds.
Cladrastis kentukea is a medium – sized, deciduous tree of the legume family that typically grows 30 feet – 50 feet tall with upright branching and a broad, rounded crown. It is noted for its pinnately compound foliage that forms a canopy of shimmering yellowish green leaves that become bright yellow in autumn.
The Tales
Genus name comes from the Greek klados, meaning branch, and thraustos, meaning fragile for the brittle twigs. The wood of this tree contains a yellow dye that distinctively colors the heartwood and gives rise to the common name of yellowwood. The yellowwood is used in small amounts for specialist furniture, gun stocks and decorative wood turning.
Cladrastis kentukea is an excellent small tree for residential lawns, particularly on smaller properties. Also may be planted near patios and terraces. They may be effectively grouped on larger properties. Roots go deep, so other plants may be easily grown underneath the branches. Yellowwood has no serious insect or disease problems. This tree tolerates dry soils once it is established. However, Yellowwood State Forest in southern Indiana has almost no Yellowwood trees growing there because of the dry soil.
Cladrastis kentukea won a Pennsylvania Horticultural Society Gold Award in 1994. Yellowwood was also selected as the 2015 Urban Tree of the Year by a vote from the members of the Society of Municipal Arborists. This tree's popularity comes from the tree's many unique features including its ability to tolerate the urban environment.
Cladrastis kentukea is one of the rarest native trees of eastern North America. It is found principally on the limestone cliffs of Kentucky, Tennessee and North Carolina. However, today the tree is being installed in locations all over the country in Zones 4 to 8. Pruning should occur in summer because cuts made in late winter or spring tend to bleed.
The Champion Yellowwood is growing at Spring Grove Cemetery in Cincinnati, Ohio. It is 75 feet (22 m) tall and has a 7 feet 4 inches. (2.2 m) trunk diameter. The tallest known Yellowwood is a slender forest tree 90 ft. (27 m) tall but only 2 ft. (0.55 m) in trunk diameter, at Plott Cove Research Natural Area in Georgia.
Sources
- Dirr, Michael A. and Keith S. Warren, “The Tree Book”, Timber Press, 2019.
- J. Frank Schmidt & Son Fact Sheet
- Missouri Botanical Garden 'Cladrastis kentukea'
- Spongberg & Ma 1997; Eastern Native Trees Society
- Wikipedia, 'Cladrastis kentukea', 11 March 2021
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Venus Dogwood
by Len Phillips
The Tree
Cornus × elwinortonii, commonly called Venus Dogwood is a hybrid noted for its vigorous habit and being a profuse bloomer of large white bracts the size of an open hand or over 6 inches (15 cm) in diameter. Venus is a medium – size deciduous tree growing 30 feet tall (10 m) and wide, with a dense, low – branched, spreading habit. It is easily grown in average soil with medium moisture, organically rich, well–drained, and acidic soil in full sun to part shade. The tree also benefits from a 2 – 4 inches (5 – 10 cm) layer of mulch to the drip line of the tree which will help keep the roots cool and moist in summer. The original tree has been field tested for twenty years and is completely winter – hardy in USDA Plant Hardiness Map Zone 5 to 8 and the AHS Heat Zone is 8 to 5.
Similar to Venus, is Stellar Pink, which is sterile, has pink bracts, and does not produce fruit. This hybrid cultivar is sometimes sold in commerce under the name of Cornus x rutgeriensis. U.S. Plant Patent PP7,207 was issued on March 27, 1990. This tree was developed at the same time as Venus.
Cornus is a genus of about 45 species of mainly deciduous shrubs and small trees. Cornus, when stressed, is susceptible to a rather large number of disease problems the most serious of which is dogwood anthracnose. Dogwood is also susceptible to leaf spot, crown canker, root rot, powdery mildew, and leaf and twig blight. Stressed trees also become vulnerable to borers. Leaf miner and scale are less serious potential insect pests. Leaf scorch may occur in full sun locations, particularly in hot, windy or drought conditions. Fortunately, Venus has been bred to avoid all these issues that stress other dogwoods.
Venus has excellent resistance to anthracnose and powdery mildew; outstanding winter hardiness, good tolerance of drought conditions, and is highly resistant to other insect pests and diseases that attack dogwoods.
The Tales
Dr. Elwin R. Orton, professor emeritus of plant biology and pathology at Rutgers University, is credited with creating Venus Dogwood. Dr. Orton focused his attention on crossing three dogwoods, Cornus kousa 'Chinensis' x Cornus nuttalii Goldspot' x Cornus kousa 'Rosea'. This work resulted in the development of the Venus Dogwood, Cornus × elwinortonii, formerly known as Cornus 'Kn30 8' Venus and ‘Stellar Pink’ (Cornus × rutgersensis) as part of the Jersey Star series of dogwoods from C. florida, C. kousa, and C. pacifica dogwoods. This hybrid species represents a long – distance artificial cross of wild species that would never meet in nature. Despite their parents being quite different in their bracts and fruits, the new hybrid species are a clear combination of their ancestors.
On March 7, 2006, the U.S. Plant Patent number PP16,309 was issued to Cornus × elwinortonii. Venus has also received awards for the best novelty tree in the years 2007 and 2008. This award winning new variety was selected as the Grower of the Year Award in 2009, as the Most Successful New Plant in the U.K.
Appreciate the Venus Dogwood for its large beautiful bracts that cover the tree in June as well as its lack of disease and pest problems. Also appreciate Dr. Orton for all the effort and years he spent creating this fine tree and all the other Stellar dogwoods.
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
by Len Phillips
The Tree
Cornus × elwinortonii, commonly called Venus Dogwood is a hybrid noted for its vigorous habit and being a profuse bloomer of large white bracts the size of an open hand or over 6 inches (15 cm) in diameter. Venus is a medium – size deciduous tree growing 30 feet tall (10 m) and wide, with a dense, low – branched, spreading habit. It is easily grown in average soil with medium moisture, organically rich, well–drained, and acidic soil in full sun to part shade. The tree also benefits from a 2 – 4 inches (5 – 10 cm) layer of mulch to the drip line of the tree which will help keep the roots cool and moist in summer. The original tree has been field tested for twenty years and is completely winter – hardy in USDA Plant Hardiness Map Zone 5 to 8 and the AHS Heat Zone is 8 to 5.
Similar to Venus, is Stellar Pink, which is sterile, has pink bracts, and does not produce fruit. This hybrid cultivar is sometimes sold in commerce under the name of Cornus x rutgeriensis. U.S. Plant Patent PP7,207 was issued on March 27, 1990. This tree was developed at the same time as Venus.
Cornus is a genus of about 45 species of mainly deciduous shrubs and small trees. Cornus, when stressed, is susceptible to a rather large number of disease problems the most serious of which is dogwood anthracnose. Dogwood is also susceptible to leaf spot, crown canker, root rot, powdery mildew, and leaf and twig blight. Stressed trees also become vulnerable to borers. Leaf miner and scale are less serious potential insect pests. Leaf scorch may occur in full sun locations, particularly in hot, windy or drought conditions. Fortunately, Venus has been bred to avoid all these issues that stress other dogwoods.
Venus has excellent resistance to anthracnose and powdery mildew; outstanding winter hardiness, good tolerance of drought conditions, and is highly resistant to other insect pests and diseases that attack dogwoods.
The Tales
Dr. Elwin R. Orton, professor emeritus of plant biology and pathology at Rutgers University, is credited with creating Venus Dogwood. Dr. Orton focused his attention on crossing three dogwoods, Cornus kousa 'Chinensis' x Cornus nuttalii Goldspot' x Cornus kousa 'Rosea'. This work resulted in the development of the Venus Dogwood, Cornus × elwinortonii, formerly known as Cornus 'Kn30 8' Venus and ‘Stellar Pink’ (Cornus × rutgersensis) as part of the Jersey Star series of dogwoods from C. florida, C. kousa, and C. pacifica dogwoods. This hybrid species represents a long – distance artificial cross of wild species that would never meet in nature. Despite their parents being quite different in their bracts and fruits, the new hybrid species are a clear combination of their ancestors.
- I can personally attest to the fact that Cornus × elwinortonii is more vigorous than any currently known cultivar of Cornus. While there are some years that the bloom is a bit limited, when the bloom is full, the entire tree is covered in large white bracts. Venus is growing in the center of the front lawn at my house. When it is blooming, people will often stop and ask me what the tree is. Even after the bracts have faded, its glossy dark green leaves will show an autumn color of reddish bronze that also raise positive responses from my neighbors.
On March 7, 2006, the U.S. Plant Patent number PP16,309 was issued to Cornus × elwinortonii. Venus has also received awards for the best novelty tree in the years 2007 and 2008. This award winning new variety was selected as the Grower of the Year Award in 2009, as the Most Successful New Plant in the U.K.
Appreciate the Venus Dogwood for its large beautiful bracts that cover the tree in June as well as its lack of disease and pest problems. Also appreciate Dr. Orton for all the effort and years he spent creating this fine tree and all the other Stellar dogwoods.
Sources
- Dirr, Michael A. and Keith S. Warren, “The Tree Book”, Timber Press, 2019.
- J. Frank Schmidt & Son Fact Sheet
- Monrovia Nusery, Plant Catalog, Venus® Dogwood, 2017
- Raver, Anne, “Cuttings: A Breeder Recalls the Majestic Dogwood”, New York Times, Nov. 21, 1999.
- Rutgers Licensing and Technology, Venus® Dogwood, 2017.
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Washington Hawthorn
by Len Phillips
The Tree
Crataegus phaenopyrum, commonly called Washington hawthorn, is native to the southeastern US but can now be found in open ground, thickets, and wooded margins throughout most of the US. Crataegus phaenopyrum is a small, low – branching, deciduous tree that typically grows 25 – 30’ tall and wide with a rounded crown. It grows best in Hardiness Zones 4–8.
Washington hawthorn shows good resistance to cedar – apple rust (Gymnosporangium juniperi – virginianae) which is the plant pathogen that causes cedar – apple rust. However, fire blight (Erwinia amylovora), fungal leaf spots, powdery mildew, cankers and apple scab are only occasional problems. Insect pests include borers, caterpillars, lace bugs, and leaf miners.
Many people rate this the best North American Hawthorn. It is very useful in both multi – stem and tree form. For street tree use, Crataegus phaenopyrum should be grown with a single leader. Thorns are present on the trunk and branches and are all the same gray color over exfoliated patches of exposed brown bark.
The Tales
Washington hawthorn is noted for its attractive flowers, foliage, fruits, and autumn color. Fragrant, 5 – petaled, white flowers in clusters (corymbs) bloom in late spring. The flowers are followed in autumn by bright red 1/4” (6 cm) diameter globose fruits (pomes) that persist throughout the winter.
The Crataegus fruit is often called a haw and the prominence of thorns give this tree its name of hawthorn. The small red berries grow closely together in large clusters and are food for squirrels and birds. Because this fruit is so attractive to birds and mammals throughout winter, there is little or no resulting litter. The blooms are also an important nectar source for bees.
The fruits have a mild flavor and can be eaten raw or cooked. The berries and flowers have cardiac benefits, and have been used to strengthen the heart and lower blood pressure. It is often taken with the flowers from the linden tree and made into a hawthorn and linden tea.
Hawthorn fruits are also made into a sweet syrup used as a heart tonic. The fruits are cooked with sugar or honey until they release their juices, and then the resulting mixture is strained and a bit of alcohol is added as a preservative.
Another use for the fruit is homemade hawthorn jelly which may be made and eaten like any jelly.
The Crataegus phaenopyrum thorny stems are clad with shallowly lobed, serrate, glossy reddish – purple leaves in spring. In summer the dark green leaves grow to 2 ½ ” (6 cm) long. The autumn leaves turn attractive shades of orange, scarlet or purple and red. The small attractive red fruits blend beautifully with the autumn leaves.
The word phaenopyrum is Greek from phaeno meaning visible. It is apparently meaning the tree has the appearance of a pear (Pyrus) tree, possibly referring to their similar flowers.
Washington Hawthorn was grown on a large scale by a Georgetown nurseryman and became popular around Washington D.C. in the late 1700's. It was named for George Washington because he planted this tree all over Mount Vernon. When it was first noted scientifically in 1883, the tree received its name from its point of origin when introduced to Pennsylvania from Mount Vernon.
It is said that American legend Paul Bunyan used the Washington hawthorn’s branches as a back scratcher.
As with other species of hawthorn, the wood is hard and can be used to make tool handles.
Many people rate this the best North American hawthorn. Because of the number and toughness of the thorns, this tree is often used as a hedge that only a very small animal would dare to pass through.
Appreciate the Washington hawthorn for its flower, fruit, leaves, bark, and form. The thorns provide a unique feature that lends this tree to being useful as a living barrier.
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
by Len Phillips
The Tree
Crataegus phaenopyrum, commonly called Washington hawthorn, is native to the southeastern US but can now be found in open ground, thickets, and wooded margins throughout most of the US. Crataegus phaenopyrum is a small, low – branching, deciduous tree that typically grows 25 – 30’ tall and wide with a rounded crown. It grows best in Hardiness Zones 4–8.
Washington hawthorn shows good resistance to cedar – apple rust (Gymnosporangium juniperi – virginianae) which is the plant pathogen that causes cedar – apple rust. However, fire blight (Erwinia amylovora), fungal leaf spots, powdery mildew, cankers and apple scab are only occasional problems. Insect pests include borers, caterpillars, lace bugs, and leaf miners.
Many people rate this the best North American Hawthorn. It is very useful in both multi – stem and tree form. For street tree use, Crataegus phaenopyrum should be grown with a single leader. Thorns are present on the trunk and branches and are all the same gray color over exfoliated patches of exposed brown bark.
The Tales
Washington hawthorn is noted for its attractive flowers, foliage, fruits, and autumn color. Fragrant, 5 – petaled, white flowers in clusters (corymbs) bloom in late spring. The flowers are followed in autumn by bright red 1/4” (6 cm) diameter globose fruits (pomes) that persist throughout the winter.
The Crataegus fruit is often called a haw and the prominence of thorns give this tree its name of hawthorn. The small red berries grow closely together in large clusters and are food for squirrels and birds. Because this fruit is so attractive to birds and mammals throughout winter, there is little or no resulting litter. The blooms are also an important nectar source for bees.
The fruits have a mild flavor and can be eaten raw or cooked. The berries and flowers have cardiac benefits, and have been used to strengthen the heart and lower blood pressure. It is often taken with the flowers from the linden tree and made into a hawthorn and linden tea.
Hawthorn fruits are also made into a sweet syrup used as a heart tonic. The fruits are cooked with sugar or honey until they release their juices, and then the resulting mixture is strained and a bit of alcohol is added as a preservative.
Another use for the fruit is homemade hawthorn jelly which may be made and eaten like any jelly.
The Crataegus phaenopyrum thorny stems are clad with shallowly lobed, serrate, glossy reddish – purple leaves in spring. In summer the dark green leaves grow to 2 ½ ” (6 cm) long. The autumn leaves turn attractive shades of orange, scarlet or purple and red. The small attractive red fruits blend beautifully with the autumn leaves.
The word phaenopyrum is Greek from phaeno meaning visible. It is apparently meaning the tree has the appearance of a pear (Pyrus) tree, possibly referring to their similar flowers.
Washington Hawthorn was grown on a large scale by a Georgetown nurseryman and became popular around Washington D.C. in the late 1700's. It was named for George Washington because he planted this tree all over Mount Vernon. When it was first noted scientifically in 1883, the tree received its name from its point of origin when introduced to Pennsylvania from Mount Vernon.
It is said that American legend Paul Bunyan used the Washington hawthorn’s branches as a back scratcher.
As with other species of hawthorn, the wood is hard and can be used to make tool handles.
Many people rate this the best North American hawthorn. Because of the number and toughness of the thorns, this tree is often used as a hedge that only a very small animal would dare to pass through.
Appreciate the Washington hawthorn for its flower, fruit, leaves, bark, and form. The thorns provide a unique feature that lends this tree to being useful as a living barrier.
Sources
- Dirr, Michael A. and Keith S. Warren, “The Tree Book”, Timber Press, 2019.
- J. Frank Schmidt & Son Fact Sheet
- Missouri Botanical Garden Crataegus phaenopyrum, Plant Finder.
- Oregon State University “Crataegus phaenopyrum” 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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Princeton Sentry Ginkgo
by Len Phillips
The Tree
Ginkgo biloba Princeton Sentry 'PNI 2720' commonly called 'Princeton Sentry' Ginkgo, is a male cultivar typically growing with an upright, narrowly conical habit, but not always uniformly columnar or fastigiate.
The distinctive fan shaped leaves of ‘Princeton Sentry’ are borne in small clusters of three to five on short, knobby spurs along the branches. The leaf blades are medium green to bluish green and have minute, parallel veins and a central dividing lobe, hence the botanical species name, biloba.
This male cultivar of Ginkgo is practically disease and insect pest free, resistant to storm damage, and casts a light shade due to the narrow columnar crown. Because it is a male cultivar, it is fruitless. Princeton Sentry will grow to about 65 feet (20 meters) tall with a 15 to 20 feet (5 to 6 m) wide spread. It tends to grow slowly. The tree is easily transplanted. It grows best in USDA Hardiness Zone 4 – 9 and AHS Heat Zone 9 – 3.
The Tales
The leaves turn a uniform golden yellow in autumn. I found the autumn color is spectacular when the leaves are back – lit by early morning or late afternoon sun. While the golden yellow will persist for several weeks, when the leaves do drop after an overnight freeze, they usually drop in a single day, forming a golden carpet on the ground around the tree.
Ginkgo trees can live for more than a thousand years, so they are best planted in large open landscapes where they have plenty of room to grow. 'Princeton Sentry' is an excellent selection for a variety of uses, including lawns, as a street tree, or a shade tree at a home, in a city park, or near a commercial building. The reason it is an excellent selection is because it tolerates most soils from acidic to neutral as long as the soil is evenly moist and fertile. It is a tough tree for difficult sites because it is tolerant of air pollution, soil compaction, and salt. Because of this, it is often installed as a city tree and in highly trafficked public areas.
In 1967, the Ginkgo biloba Princeton Sentry 'PNI 2720', was introduced into the nursery trade. It was selected from a Ginkgo biloba fastigiate form that was growing among a large plantation of seedling grown trees at the Princeton Nurseries in Princeton, New Jersey. Numerous male trees from this plantation were grafted in 1938 and moved into nursery rows for further development and evaluation. They all grew well, but most of them developed unshapely crowns, unsuited for street installations. Of the original 32 selections, seven had superior branching structure and were selected for further study. By 1967 one of the trees was clearly the best of them all and was named Princeton Sentry, and was granted plant patent #2726.
This outstanding columnar tree combines the unique narrow head of the Lombardy Poplar shape with the long life and immunity to pests and disease that are characteristic of the Ginkgo. Princeton Sentry is propagated vegetatively, either by grafting or bud grafting on seedling Ginkgo trees. Sometimes they are started by rooting a softwood cutting.
Ginkgo biloba Princeton Sentry 'PNI 2720', was selected as the 1996 Urban Tree of the Year by a vote from the members of the Society of Municipal Arborists. This tree's popularity comes from having almost no pest problems, low maintenance after an early pruning, tolerance of soils, salt, and pollutants, and no problem fruits.
Appreciate Princeton Sentry Ginkgo because it is seedless while being a very tough city tree.
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
by Len Phillips
The Tree
Ginkgo biloba Princeton Sentry 'PNI 2720' commonly called 'Princeton Sentry' Ginkgo, is a male cultivar typically growing with an upright, narrowly conical habit, but not always uniformly columnar or fastigiate.
The distinctive fan shaped leaves of ‘Princeton Sentry’ are borne in small clusters of three to five on short, knobby spurs along the branches. The leaf blades are medium green to bluish green and have minute, parallel veins and a central dividing lobe, hence the botanical species name, biloba.
This male cultivar of Ginkgo is practically disease and insect pest free, resistant to storm damage, and casts a light shade due to the narrow columnar crown. Because it is a male cultivar, it is fruitless. Princeton Sentry will grow to about 65 feet (20 meters) tall with a 15 to 20 feet (5 to 6 m) wide spread. It tends to grow slowly. The tree is easily transplanted. It grows best in USDA Hardiness Zone 4 – 9 and AHS Heat Zone 9 – 3.
The Tales
The leaves turn a uniform golden yellow in autumn. I found the autumn color is spectacular when the leaves are back – lit by early morning or late afternoon sun. While the golden yellow will persist for several weeks, when the leaves do drop after an overnight freeze, they usually drop in a single day, forming a golden carpet on the ground around the tree.
Ginkgo trees can live for more than a thousand years, so they are best planted in large open landscapes where they have plenty of room to grow. 'Princeton Sentry' is an excellent selection for a variety of uses, including lawns, as a street tree, or a shade tree at a home, in a city park, or near a commercial building. The reason it is an excellent selection is because it tolerates most soils from acidic to neutral as long as the soil is evenly moist and fertile. It is a tough tree for difficult sites because it is tolerant of air pollution, soil compaction, and salt. Because of this, it is often installed as a city tree and in highly trafficked public areas.
In 1967, the Ginkgo biloba Princeton Sentry 'PNI 2720', was introduced into the nursery trade. It was selected from a Ginkgo biloba fastigiate form that was growing among a large plantation of seedling grown trees at the Princeton Nurseries in Princeton, New Jersey. Numerous male trees from this plantation were grafted in 1938 and moved into nursery rows for further development and evaluation. They all grew well, but most of them developed unshapely crowns, unsuited for street installations. Of the original 32 selections, seven had superior branching structure and were selected for further study. By 1967 one of the trees was clearly the best of them all and was named Princeton Sentry, and was granted plant patent #2726.
This outstanding columnar tree combines the unique narrow head of the Lombardy Poplar shape with the long life and immunity to pests and disease that are characteristic of the Ginkgo. Princeton Sentry is propagated vegetatively, either by grafting or bud grafting on seedling Ginkgo trees. Sometimes they are started by rooting a softwood cutting.
Ginkgo biloba Princeton Sentry 'PNI 2720', was selected as the 1996 Urban Tree of the Year by a vote from the members of the Society of Municipal Arborists. This tree's popularity comes from having almost no pest problems, low maintenance after an early pruning, tolerance of soils, salt, and pollutants, and no problem fruits.
Appreciate Princeton Sentry Ginkgo because it is seedless while being a very tough city tree.
Sources
- Dirr, Michael A. and Keith S. Warren, “The Tree Book”, Timber Press, 2019.
- Gilman, Edward F. and Dennis G. Watson, “Ginkgo biloba ‘Princeton Sentry", US Forest Service, Fact Sheet ST – 278, November 1993.
- J. Frank Schmidt & Son Fact Sheet
- Learn 2 Grow, “Ginkgo biloba 'Princeton Sentry',” Plant Search, 2017.
- Missouri Botanical Garden, Ginkgo biloba 'Princeton Sentry', 2017.
- Phillips, Leonard, “1996 Urban Tree of the Year,” City Trees, March/April 1996.
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Skyline Honeylocust
by Len Phillips
The Tree
Gleditsia triacanthos inermis 'Skycole', commonly called Skyline® Honeylocust, was discovered in 1955.
The flowers are mostly male, and are borne in 1 – 1/2 to 3 inches (4 to 8 cm) long racemes, with one female flower at the tip of the raceme. However, Skyline® is substantially seedless but occasionally seedpods develop that contain a sweet gummy substance that gives honeylocust its common name.
The leaves are 6 to 10 inches (15 to 27 cm) long and mostly bi-pinnate. The leaves have 10 to 16 leaflets and are larger than those on the common thornless honeylocust. The green leaves cast a sun – dappled shade in summer, turn an attractive yellow in autumn, and create relatively little mess when the leaflets drop to the ground. Skyline® is best grown in organically rich, moist, well–drained soils in full sun and within USDA Hardiness Zones 3 – 9 and AHS Heat Zones 9 – 1. It is tolerant of a wide range of soils as well as wind, high summer heat, drought and saline conditions. It typically grows 30 – 45 feet (9m – 14m) tall and 25 – 45 feet (8m – 14m) wide, with a pyramidal crown and a central leader that becomes dome – shaped with age.
Skyline® is somewhat susceptible to numerous potential disease problems, including leaf spot, canker, witches’ broom, powdery mildew, and rust. Borers and webworms are common insect problems in some areas. Bagworms, plant bug, leafhopper, spider mites, and leaf miner may appear, but Skyline® is reputedly resistant to deer and rabbit damage. These problems are becoming worse because this tree is being overused in our city landscapes, and because it is such a desirable tree to grow.
The Tales
Skyline® Honeylocust was discovered by David Barrett Cole, in Mentor Township, Ohio. The original parent was a seedling grown at the Cole Nursery Company in Painesville, Ohio. David discovered this tree among a plantation of approximately 10,000 thornless honeylocust seedlings being grown from seed. He was looking for trees exhibiting a tendency toward having strong, sturdy, straight trunks and no thorns. The trunk has gray – brown, shallowly fissured bark.
David was also impressed with Skyline's angle of the sturdy branches from the trunk that would assure relatively strong unions. The branches are well spaced and emerge in all directions from the trunk, giving no indication of a one – sided or flat – branch arrangement often a characteristic of the species. He also noted that the growth habit was noticeably upright compared with the wide spreading nature of the species that can be found in many open landscapes.
David was also looking for a honeylocust with very dark green leaflets. Skyline's newly formed leaves show bronze tips while the mature leaves are dark green on both sides and turn dull yellow before dropping in autumn. David propagated this thornless honeylocust tree asexually by budding, and in this manner, perpetuated all of its desirable features. On July 16, 1957, Plant Patent number 1619, was granted for Gleditsia triacanthos inermis 'Skycole', Skyline® Honeylocust.
Skyline® Honeylocust was selected as the 1999 Urban Tree of the Year by a vote from the members of the Society of Municipal Arborists. This tree's popularity comes from being an adaptable tree for shade on private property as well as for streets and parking lots.
Appreciate this tough, medium–sized fine textured honeylocust that casts a light shade, will not kill lawn grasses, and has leaves that will blow away in autumn. It is considered to be the most popular honeylocust currently being grown.
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
by Len Phillips
The Tree
Gleditsia triacanthos inermis 'Skycole', commonly called Skyline® Honeylocust, was discovered in 1955.
The flowers are mostly male, and are borne in 1 – 1/2 to 3 inches (4 to 8 cm) long racemes, with one female flower at the tip of the raceme. However, Skyline® is substantially seedless but occasionally seedpods develop that contain a sweet gummy substance that gives honeylocust its common name.
The leaves are 6 to 10 inches (15 to 27 cm) long and mostly bi-pinnate. The leaves have 10 to 16 leaflets and are larger than those on the common thornless honeylocust. The green leaves cast a sun – dappled shade in summer, turn an attractive yellow in autumn, and create relatively little mess when the leaflets drop to the ground. Skyline® is best grown in organically rich, moist, well–drained soils in full sun and within USDA Hardiness Zones 3 – 9 and AHS Heat Zones 9 – 1. It is tolerant of a wide range of soils as well as wind, high summer heat, drought and saline conditions. It typically grows 30 – 45 feet (9m – 14m) tall and 25 – 45 feet (8m – 14m) wide, with a pyramidal crown and a central leader that becomes dome – shaped with age.
Skyline® is somewhat susceptible to numerous potential disease problems, including leaf spot, canker, witches’ broom, powdery mildew, and rust. Borers and webworms are common insect problems in some areas. Bagworms, plant bug, leafhopper, spider mites, and leaf miner may appear, but Skyline® is reputedly resistant to deer and rabbit damage. These problems are becoming worse because this tree is being overused in our city landscapes, and because it is such a desirable tree to grow.
The Tales
Skyline® Honeylocust was discovered by David Barrett Cole, in Mentor Township, Ohio. The original parent was a seedling grown at the Cole Nursery Company in Painesville, Ohio. David discovered this tree among a plantation of approximately 10,000 thornless honeylocust seedlings being grown from seed. He was looking for trees exhibiting a tendency toward having strong, sturdy, straight trunks and no thorns. The trunk has gray – brown, shallowly fissured bark.
David was also impressed with Skyline's angle of the sturdy branches from the trunk that would assure relatively strong unions. The branches are well spaced and emerge in all directions from the trunk, giving no indication of a one – sided or flat – branch arrangement often a characteristic of the species. He also noted that the growth habit was noticeably upright compared with the wide spreading nature of the species that can be found in many open landscapes.
David was also looking for a honeylocust with very dark green leaflets. Skyline's newly formed leaves show bronze tips while the mature leaves are dark green on both sides and turn dull yellow before dropping in autumn. David propagated this thornless honeylocust tree asexually by budding, and in this manner, perpetuated all of its desirable features. On July 16, 1957, Plant Patent number 1619, was granted for Gleditsia triacanthos inermis 'Skycole', Skyline® Honeylocust.
Skyline® Honeylocust was selected as the 1999 Urban Tree of the Year by a vote from the members of the Society of Municipal Arborists. This tree's popularity comes from being an adaptable tree for shade on private property as well as for streets and parking lots.
Appreciate this tough, medium–sized fine textured honeylocust that casts a light shade, will not kill lawn grasses, and has leaves that will blow away in autumn. It is considered to be the most popular honeylocust currently being grown.
Sources
- Chicago Botanical Garden, Skyline Honeylocust, October 5, 2017.
- Dirr, Michael A. and Keith S. Warren, “The Tree Book”, Timber Press, 2019.
- Gilman, Edward F. and Dennis G. Watson, “Gleditsia triacanthos inermis 'Skycole', Skyline® Honeylocust’”, US Forest Service, Fact Sheet ST – 278, November 1993.
- J. Frank Schmidt & Son Fact Sheet
- Learn 2 Grow, “Gleditsia triacanthos inermis 'Skycole', Skyline® Honeylocust” Plant Search, 2017.
- Missouri Botanical Garden, Gleditsia triacanthos inermis 'Skycole', Skyline® Honeylocust, 2017.
- Wikipedia, Gleditsia triacanthos inermis 'Skycole', Skyline® Honeylocust, 2017.
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Tulip Tree
by Len Phillips
The Tree
Liriodendron tulipifera, is commonly called Tulip tree, tulip poplar, whitewood, fiddle tree, and yellow – poplar. It is a large, stately, deciduous tree, native to eastern North America. The external resemblance of the “cup – shaped” flowers resembling tulips, resulted in the name, tulip tree. The color of the wood gives it the name whitewood. It is sometimes called "fiddle tree," because its leaves, with their arched bases and in–cut sides, suggest the violin shape. It is called a yellow poplar largely because of the fluttering habit of its leaves in autumn.
Tulip trees typically grow 60 – 90 feet (20 – 30 m) tall and 35 to 50 feet (10 – 15 m) wide, with a pyramidal to broad or oval canopy. It grows to more than 160 feet (50 m) tall in the forests of the Appalachian Mountains. On the U.S. West Coast they have been known to surpass 200 feet tall. They grow best in USDA Hardiness Zones 5 – 9 and AHS Heat Zones 9 – 2, in a forest that has thick dark topsoil. It has an upright trunk that may reach 4 to 10 feet (1 to 3 m) in diameter. The branchlets are smooth, and lustrous, initially reddish, maturing to dark gray, and finally to brown.
Liriodendron trees grow readily from seeds, which should be sown in a fine soft mound, and in a cool and shady location. If sown in autumn they come up the following spring, but if sown in spring they often remain a year in the ground.
Tulips trees have one of the most distinctive leaves of any tree. They are up to 8 inches (20 cm) long and wide. They have four lobes and are smooth and shining above, paler green beneath, and medium green before turning golden yellow in autumn.
Liriodendron trees have fleshy roots that are easily broken if handled roughly. Tulip trees prefer deep, rich, and rather moist soil and transplanting should be done in early spring, before leaf – out. This timing is especially important in the more northern areas. Most tulip trees have low tolerance to drought.
The Tales
Few eastern American landscape trees reach great heights as quickly as Liriodendron tulipifera. This tree is also substantially strong – wooded and long – lived. One of the oldest known specimens exists in the Great Smoky Mountains National Park and is believed to be over 500 years old. It is a fast – growing tree without the common problems of weak wood strength and short lifespan often seen in other fast – growing species.
Liriodendron tulipifera trees have perfect, solitary, terminal flowers in the spring that are pale green or yellow with an orange band at the base of each petal. Although the tulip – shaped flowers are 2 inches in length, they can go unnoticed on large trees because the upward facing flowers appear after the leaves are fully developed. They yield large quantities of nectar. This tree is a major honey plant in the eastern United States, yielding a dark reddish, fairly strong flavored honey, which gets mixed reviews as a table honey but is favorably regarded by bakers.
The flowers are followed by a dry, scaly, oblong, cone – shaped brown fruit, each bearing numerous winged seeds that are dispersed by wind. The seeds typically travel a distance equal to 4 to 5 tiimes the height of the tree and remain viable for 4 to 7 years. The seeds are not one of the most important food sources for wildlife, but they are eaten by a number of birds and mammals.
Young trees are quite shade tolerant, so they can withstand the low light of the forest understory. The low light does cause early branch drop for the lower two thirds of the tree, which give it very valuable knot – free lumber. The bark is brown and furrowed.
Liriodendron was a favorite tree of both George Washington and Thomas Jefferson, who had large specimens at their homes. The trees at Mt. Vernon were planted in 1785 and are still alive and flourishing today.
The Marquis de Lafayette also loved the tulip poplar. He took saplings home to France to be planted at Versailles and he gave one personally to Marie Antoinette.
The tulip tree is the host tree for Eastern tiger swallowtail butterflies (Papilio glaucus), honeybees, hummingbirds, and the tulip tree silk moth (Callosamia angulifera), which all use the leaves as a food source. Aphids are attracted to the honeydew leaves and ants are attracted to the aphids.
A refined cultivar of our familiar North American native tulip tree is Liriodendron tulipifera ‘JFS – Oz’, Emerald City® Tulip Tree. It is valued most for providing shade and it is a flowering tree that offers predictable performance in a variable species. Its unique yellow flowers with orange centers bloom in May and June, and at a younger age than is typical of the species. The deep green, glossy summer foliage turns a bright, clear yellow autumn color that stands in bright contrast to the typical red and orange forest tree tones. Tall and relatively narrow oval for a tree of its height, this refined cultivar of the handsome North American native Liriodendron tulipifera presents a slightly compact canopy with a dominant central leader and symmetrical, upright branches. This distinctive cultivar assures predictable performance in a variable species.
The soft, fine – grained wood of tulip trees is very widely used where a cheap, easy–to–work and stable wood is needed. The sapwood is usually a creamy off–white color, while the heartwood is usually a pale green. It is clearly the wood of choice for use in organs, due to its ability to take a fine, smooth, precisely cut surface that effectively seals against pipes and valves. It is commonly used for siding clapboards and is also used for interior finish of houses, for panels of carriages, for coffin boxes, pattern timber, and wooden ware. During scarcity of the better qualities of white pine, tulip wood has taken its place particularly when very wide boards are required. It also has a reputation for being resistant to termites, and house and barn sills were often made of tulip poplar beams. Native Americans made their dugout canoes from its trunk.
Liriodendron tulipifera has been selected as the 2018 Urban Tree of the Year by a vote from the members of the Society of Municipal Arborists. It is also the state tree in Kentucky, Indiana, and Tennessee. This tree's popularity comes from their grand and stately stature, the delightful yellow flowers, and being an easy tree to grow. However, their shallow roots make it difficult to garden under, so it is best planted as a large shade and lawn specimen for open lawns, wide medians, and public parks.
Appreciate the Tulip Tree for its very unusual yellow flower and distinctive leaves, and its qualities as a fast- growing tree with a grand and stately stature that provides many useful lumber products.
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
by Len Phillips
The Tree
Liriodendron tulipifera, is commonly called Tulip tree, tulip poplar, whitewood, fiddle tree, and yellow – poplar. It is a large, stately, deciduous tree, native to eastern North America. The external resemblance of the “cup – shaped” flowers resembling tulips, resulted in the name, tulip tree. The color of the wood gives it the name whitewood. It is sometimes called "fiddle tree," because its leaves, with their arched bases and in–cut sides, suggest the violin shape. It is called a yellow poplar largely because of the fluttering habit of its leaves in autumn.
Tulip trees typically grow 60 – 90 feet (20 – 30 m) tall and 35 to 50 feet (10 – 15 m) wide, with a pyramidal to broad or oval canopy. It grows to more than 160 feet (50 m) tall in the forests of the Appalachian Mountains. On the U.S. West Coast they have been known to surpass 200 feet tall. They grow best in USDA Hardiness Zones 5 – 9 and AHS Heat Zones 9 – 2, in a forest that has thick dark topsoil. It has an upright trunk that may reach 4 to 10 feet (1 to 3 m) in diameter. The branchlets are smooth, and lustrous, initially reddish, maturing to dark gray, and finally to brown.
Liriodendron trees grow readily from seeds, which should be sown in a fine soft mound, and in a cool and shady location. If sown in autumn they come up the following spring, but if sown in spring they often remain a year in the ground.
Tulips trees have one of the most distinctive leaves of any tree. They are up to 8 inches (20 cm) long and wide. They have four lobes and are smooth and shining above, paler green beneath, and medium green before turning golden yellow in autumn.
Liriodendron trees have fleshy roots that are easily broken if handled roughly. Tulip trees prefer deep, rich, and rather moist soil and transplanting should be done in early spring, before leaf – out. This timing is especially important in the more northern areas. Most tulip trees have low tolerance to drought.
The Tales
Few eastern American landscape trees reach great heights as quickly as Liriodendron tulipifera. This tree is also substantially strong – wooded and long – lived. One of the oldest known specimens exists in the Great Smoky Mountains National Park and is believed to be over 500 years old. It is a fast – growing tree without the common problems of weak wood strength and short lifespan often seen in other fast – growing species.
Liriodendron tulipifera trees have perfect, solitary, terminal flowers in the spring that are pale green or yellow with an orange band at the base of each petal. Although the tulip – shaped flowers are 2 inches in length, they can go unnoticed on large trees because the upward facing flowers appear after the leaves are fully developed. They yield large quantities of nectar. This tree is a major honey plant in the eastern United States, yielding a dark reddish, fairly strong flavored honey, which gets mixed reviews as a table honey but is favorably regarded by bakers.
The flowers are followed by a dry, scaly, oblong, cone – shaped brown fruit, each bearing numerous winged seeds that are dispersed by wind. The seeds typically travel a distance equal to 4 to 5 tiimes the height of the tree and remain viable for 4 to 7 years. The seeds are not one of the most important food sources for wildlife, but they are eaten by a number of birds and mammals.
Young trees are quite shade tolerant, so they can withstand the low light of the forest understory. The low light does cause early branch drop for the lower two thirds of the tree, which give it very valuable knot – free lumber. The bark is brown and furrowed.
Liriodendron was a favorite tree of both George Washington and Thomas Jefferson, who had large specimens at their homes. The trees at Mt. Vernon were planted in 1785 and are still alive and flourishing today.
The Marquis de Lafayette also loved the tulip poplar. He took saplings home to France to be planted at Versailles and he gave one personally to Marie Antoinette.
The tulip tree is the host tree for Eastern tiger swallowtail butterflies (Papilio glaucus), honeybees, hummingbirds, and the tulip tree silk moth (Callosamia angulifera), which all use the leaves as a food source. Aphids are attracted to the honeydew leaves and ants are attracted to the aphids.
A refined cultivar of our familiar North American native tulip tree is Liriodendron tulipifera ‘JFS – Oz’, Emerald City® Tulip Tree. It is valued most for providing shade and it is a flowering tree that offers predictable performance in a variable species. Its unique yellow flowers with orange centers bloom in May and June, and at a younger age than is typical of the species. The deep green, glossy summer foliage turns a bright, clear yellow autumn color that stands in bright contrast to the typical red and orange forest tree tones. Tall and relatively narrow oval for a tree of its height, this refined cultivar of the handsome North American native Liriodendron tulipifera presents a slightly compact canopy with a dominant central leader and symmetrical, upright branches. This distinctive cultivar assures predictable performance in a variable species.
The soft, fine – grained wood of tulip trees is very widely used where a cheap, easy–to–work and stable wood is needed. The sapwood is usually a creamy off–white color, while the heartwood is usually a pale green. It is clearly the wood of choice for use in organs, due to its ability to take a fine, smooth, precisely cut surface that effectively seals against pipes and valves. It is commonly used for siding clapboards and is also used for interior finish of houses, for panels of carriages, for coffin boxes, pattern timber, and wooden ware. During scarcity of the better qualities of white pine, tulip wood has taken its place particularly when very wide boards are required. It also has a reputation for being resistant to termites, and house and barn sills were often made of tulip poplar beams. Native Americans made their dugout canoes from its trunk.
Liriodendron tulipifera has been selected as the 2018 Urban Tree of the Year by a vote from the members of the Society of Municipal Arborists. It is also the state tree in Kentucky, Indiana, and Tennessee. This tree's popularity comes from their grand and stately stature, the delightful yellow flowers, and being an easy tree to grow. However, their shallow roots make it difficult to garden under, so it is best planted as a large shade and lawn specimen for open lawns, wide medians, and public parks.
Appreciate the Tulip Tree for its very unusual yellow flower and distinctive leaves, and its qualities as a fast- growing tree with a grand and stately stature that provides many useful lumber products.
Sources
- Dirr, Michael A. and Keith S. Warren, “The Tree Book”, Timber Press, 2019.
- J. Frank Schmidt & Son Fact Sheet
- Jonnes, Jill, “Urban Forests”, Penguin Books, 2016.
- Learn 2 Grow, “Liriodendron tulipifera” Plant Search, 2017.
- Missouri Botanical Garden, Liriodendron tulipifera, 2017
- Wikipedia, Liriodendron tulipifera, December 4, 2017.
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Black Tupelo
by Len Phillips
The Tree
Nyssa sylvatica, commonly called Black Tupelo also called tupelo, black gum, sour gum, bee gum, and pepperidge is a slow – growing, deciduous tree, native to eastern North America from southern Canada to central Florida and west to Texas and Mexico. One city with an abundance of this tree growing within its borders is Tupelo, Mississippi. It is primarily a lowland tree found in wet woods, alluvial stream bottomlands, and pond peripheries, but tupelo can also be found on dry rocky wooded slopes and ravines. It grows best in sheltered but not crowded locations in USDA Hardiness Zone 5 – 9 and AHS Heat Zone 9 – 7. It has also been found to be happily growing in fairly compact city soils.
Tupelo is a stately tree with a straight trunk and a pyramidal shape in youth, and spreading with age to a rounded crown with the branches extending outward at right angles horizontally or drooping a little, making a long – narrow, cone – like head. The bark is dark gray and flaky when young, but it becomes furrowed with age. It typically grows to 65 – 80 feet (20 – 25 m) tall, and occasionally up to 100 feet (31 m) tall. The champion Nyssa is 110 feet (34 m) tall, with a crown spread of 81 feet (28 m) and a trunk circumference of 20 feet (6m).
The dark green leaves are usually wider at the tip than at the base and are variable. They can be oval, elliptical, or obovate, and 2 – 5 inches (5 – 12 cm) long. The leaves have lustrous upper surfaces and paler below, with entire, often wavy margins. In autumn the foliage turns yellow or orange, purple, and eventually becomes an intense bright scarlet.
The flowers are very small, in greenish – white in clusters at the top of a long stalk and a rich source or nectar for bees. They are often dioecious so a male and female tree in proximity are required to set seed. However, male trees may also set some fruits. The sour gum fruits resemble small bluish – black olives that are bitter to sour tasting but are very popular with small bird species. There are from one to three fruits together on a long slender stalk. The fruits are a valuable energy food for birds, and deer are extremely fond of the leaves on seedlings and saplings, to the point where large populations of deer can make establishment of the tree almost impossible. For comparison, mature trees are largely left alone by deer and other animals. There are no serious insect or disease problems, but Nyssa sylvatica has some susceptibility to leaf spots, canker, rust, leaf miner and scale.
The Tales
Nyssa sylvatica is cultivated as an ornamental tree in parks and large gardens, where it is often used as a specimen or shade tree. It also grows well in moist woodland gardens or naturalized areas or in low spots subject to periodic flooding or in boggy areas. It does not like alkaline soils and road salt. Although slow – growing, it still needs to be sited in an area which affords plenty of room for future growth, particularly since it is so difficult to transplant. Nyssa sylvatica forms a large deep taproot when young that makes transplanting difficult. Because of this, it is fairly uncommon in cultivation and the nursery trade, but where it is grown, it makes a wonderful shade tree with distinct form and foliage.
Nyssa sylvatica is a major source of wild honey in many areas within its range. Hollow sections of black gum trunks were formerly used as bee gums by beekeepers, hence the common name of bee gum.
Black Tupelo was selected as the 2008 Urban Tree of the Year by a vote from the members of the Society of Municipal Arborists. This tree's popularity comes from being outstanding in autumn and its ease of maintenance.
The arborists also like the fissured gray bark that provides winter interest and it is adaptable to city conditions.
Appreciate the beautiful autumn colors of Nyssa as well as birds and deer that are attracted to this tree in late summer.
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
by Len Phillips
The Tree
Nyssa sylvatica, commonly called Black Tupelo also called tupelo, black gum, sour gum, bee gum, and pepperidge is a slow – growing, deciduous tree, native to eastern North America from southern Canada to central Florida and west to Texas and Mexico. One city with an abundance of this tree growing within its borders is Tupelo, Mississippi. It is primarily a lowland tree found in wet woods, alluvial stream bottomlands, and pond peripheries, but tupelo can also be found on dry rocky wooded slopes and ravines. It grows best in sheltered but not crowded locations in USDA Hardiness Zone 5 – 9 and AHS Heat Zone 9 – 7. It has also been found to be happily growing in fairly compact city soils.
Tupelo is a stately tree with a straight trunk and a pyramidal shape in youth, and spreading with age to a rounded crown with the branches extending outward at right angles horizontally or drooping a little, making a long – narrow, cone – like head. The bark is dark gray and flaky when young, but it becomes furrowed with age. It typically grows to 65 – 80 feet (20 – 25 m) tall, and occasionally up to 100 feet (31 m) tall. The champion Nyssa is 110 feet (34 m) tall, with a crown spread of 81 feet (28 m) and a trunk circumference of 20 feet (6m).
The dark green leaves are usually wider at the tip than at the base and are variable. They can be oval, elliptical, or obovate, and 2 – 5 inches (5 – 12 cm) long. The leaves have lustrous upper surfaces and paler below, with entire, often wavy margins. In autumn the foliage turns yellow or orange, purple, and eventually becomes an intense bright scarlet.
The flowers are very small, in greenish – white in clusters at the top of a long stalk and a rich source or nectar for bees. They are often dioecious so a male and female tree in proximity are required to set seed. However, male trees may also set some fruits. The sour gum fruits resemble small bluish – black olives that are bitter to sour tasting but are very popular with small bird species. There are from one to three fruits together on a long slender stalk. The fruits are a valuable energy food for birds, and deer are extremely fond of the leaves on seedlings and saplings, to the point where large populations of deer can make establishment of the tree almost impossible. For comparison, mature trees are largely left alone by deer and other animals. There are no serious insect or disease problems, but Nyssa sylvatica has some susceptibility to leaf spots, canker, rust, leaf miner and scale.
The Tales
Nyssa sylvatica is cultivated as an ornamental tree in parks and large gardens, where it is often used as a specimen or shade tree. It also grows well in moist woodland gardens or naturalized areas or in low spots subject to periodic flooding or in boggy areas. It does not like alkaline soils and road salt. Although slow – growing, it still needs to be sited in an area which affords plenty of room for future growth, particularly since it is so difficult to transplant. Nyssa sylvatica forms a large deep taproot when young that makes transplanting difficult. Because of this, it is fairly uncommon in cultivation and the nursery trade, but where it is grown, it makes a wonderful shade tree with distinct form and foliage.
Nyssa sylvatica is a major source of wild honey in many areas within its range. Hollow sections of black gum trunks were formerly used as bee gums by beekeepers, hence the common name of bee gum.
Black Tupelo was selected as the 2008 Urban Tree of the Year by a vote from the members of the Society of Municipal Arborists. This tree's popularity comes from being outstanding in autumn and its ease of maintenance.
The arborists also like the fissured gray bark that provides winter interest and it is adaptable to city conditions.
Appreciate the beautiful autumn colors of Nyssa as well as birds and deer that are attracted to this tree in late summer.
Sources
- Dirr, Michael A. and Keith S. Warren, “The Tree Book”, Timber Press, 2019.
- J. Frank Schmidt & Son Fact Sheet
- Learn 2 Grow, “Nyssa sylvatica” Plant Search, 2017.
- Missouri Botanical Garden, 'Nyssa sylvatica', 2017
- Wikipedia, 'Nyssa sylvatica', December 19, 2017
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
Swamp White Oak
by Len Phillips
The Tree
Quercus bicolor, commonly called swamp white oak, is a North American species of medium – sized deciduous trees in the beech family. It is common in America's mixed forests from Nova Scotia to South Carolina, west to Ontario, Minnesota, and Tennessee. The tree generally occurs singly rather than in groves of swamp white oak. In upland forests it grows alongside bur oak. In lowlands, the tree grows with other oaks, red maple, hickory, black walnut, linden, elm, honeylocust, and ash. The swamp white oak typically grows on wet soils as found in
broad stream valleys, low – lying fields, and the margins of lakes, ponds, or wetlands. The tree will tolerate significant soil compaction. It is not found where flooding is permanent, although it can survive in a variety of habitats and live up to 350 years. Quercus bicolor is found within a very wide range of temperatures and rainfall and generally does best in USDA Hardiness Zones 4–8 and AHS Heat Zones 8–1.
Swamp white oak grows rapidly, with a broad, rounded crown and a short trunk and can reach 60 to 80 feet (18 to 24 meters) tall with the tallest known tree reaching 105 feet (33.5 m) and spread 102 feet (32.5 m) in Franklin Township, NJ. Generally, the swamp white oak is a durable and long – lived tree, but it is susceptible to numerous potential diseases and insect pests however, none are serious. Chlorosis or yellowing of the leaves while the veins remain green, often occurs when soils are alkaline and have a pH above 7.2.
Young plants from containers, young B&B trees and bare – root transplants are best installed in early spring at a young age. Transplanting this tree may be difficult because of the strong and rapid development of the taproot. Acorns planted in autumn at permanent positions give the best results. Then Quercus bicolor develops a double layer root system which allows it to grow well in areas that are flooded in spring but markedly dry in summer.
The swamp white oak develops a strong, upright trunk with distinctly dark gray exfoliating bark that is scaly, often peeling off in large, ragged, papery curls. It forms hybrids with bur oak where they occur together in the wild.
The bi–colored leaves are shiny dark green above and velvety white pubescence underneath, and are not like most oaks. Instead they are shaped like a broad, heavily toothed oval, approximately 5 – 7“(12–18 cm) long and 3 – 4 inches (7–11 cm) wide. In autumn, they turn brown, yellow – brown, or sometimes reddish, but generally, the color is not as reliable as other trees.
Very small, almost insignificant flowers are found on separate male and female catkins on the same tree in spring. The fruits are acorns which mature in early autumn. The light brown acorn is a half to one inch (1.5 – 2 cm) long and a half to three quarters inch (1–2 cm) wide. The acorn matures about 6 months after pollination. Seed production in swamp white oak begins at 20–30 years of age. The greatest production occurs between 75–100 years of age. Good seed crops are produced every 3–5 years.
The acorns are sweet and are an important food for wildlife such as squirrels, mice, white tailed deer, beaver, black bear, and a variety of birds, including ducks and turkey. Native Americans and pioneers ate the acorns raw or cooked. They have been ground into a powder and used as a thickening in stews or mixed with cereals for making bread. Roasted acorns have been ground and used as a coffee substitute. Bitterness of the tannins is removed by leaching in running water.
The Tales
Quercus bicolor is often planted on highway rights–of–way and is frequently used as a shade tree for large lawns, golf courses, parks, and naturalized areas. Because of this and it not having any serious pest issues and very few maintenance concerns, this oak was selected by the Society of Municipal Arborists as its Urban Tree of the Year in 1998.
Forests of elm, ash, and cottonwood will evolve to become oak dominated forests that include this oak. Then oak forests will evolve to become hickory and beech forests.
The swamp white oak is one of the more important trees that provide high quality lumber. The wood of swamp white oak is light brown, close – grained, heavy, and hard. It is similar to that of white oak (Q. alba) and usually is cut and sold under white oak name. However, the lateral branches of swamp white oak tend to persist so the wood is knotty and less valuable. The wood is used for furniture, cabinets, veneers, interior finishing, and flooring, as well as for boxes, crates, fence posts, railroad ties, and beams and boards for general construction. As with white oak, the wood provides tight cooperage and was once widely used in making barrels and kegs. Oak galls, caused by the activity of the larvae of various insects, can be used as a source of tannin and dye. They also are strongly astringent and can be used in the treatment of hemorrhages, chronic diarrhea, and dysentery. Some Native Americans used swamp white oak to treat cholera, broken bones, and consumption. Mulch from the dead leaves is reported to repel slugs, grubs, and various insects.
Quercus bicolor is used in large formal landscapes and was selected to be the featured tree in the 9/11 memorial landscape in New York City. It has also become a very popular parent in many new oak hybrids currently appearing in nurseries.
Wildlife such as deer, ducks, and geese, as well as other animals, are attracted to this tree for cover and when the acorns are dropping in autumn.
Quercus bicolor American Dream 'JFS – KW12' is a cultivar that is upright and becoming broadly pyramidal with age. This tree has deep green glossy leaves and greatly improved resistance to common diseases. It is especially good in heat and drought. The selection of this tree began in 1998 at a nursery in Oregon. For the next seven years, Keith Warrren examined over 10,000 Swamp white oak seedlings selecting 66 trees with superior features. They were identified, selected and transplanted for further study. Eventually 18 trees were chosen for further evaluation. In 2002 one tree was identified for its vigorous growth habit, its large deep green glossy leaves, and its excellent branch structure as well as its resistance to powdery mildew and oak anthracnose. In 2009, the stock was greatly increased. The decision was made to introduce this tree in 2012. Today, American Dream 'JFS – KW12', is receiving plaudits nationwide.
Appreciate the Swamp White Oak for its ability to grow well in our cities, have no serious pest problems, very few maintenance issues, and its unique 2–layer root system to tolerate problem soils.
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.
by Len Phillips
The Tree
Quercus bicolor, commonly called swamp white oak, is a North American species of medium – sized deciduous trees in the beech family. It is common in America's mixed forests from Nova Scotia to South Carolina, west to Ontario, Minnesota, and Tennessee. The tree generally occurs singly rather than in groves of swamp white oak. In upland forests it grows alongside bur oak. In lowlands, the tree grows with other oaks, red maple, hickory, black walnut, linden, elm, honeylocust, and ash. The swamp white oak typically grows on wet soils as found in
broad stream valleys, low – lying fields, and the margins of lakes, ponds, or wetlands. The tree will tolerate significant soil compaction. It is not found where flooding is permanent, although it can survive in a variety of habitats and live up to 350 years. Quercus bicolor is found within a very wide range of temperatures and rainfall and generally does best in USDA Hardiness Zones 4–8 and AHS Heat Zones 8–1.
Swamp white oak grows rapidly, with a broad, rounded crown and a short trunk and can reach 60 to 80 feet (18 to 24 meters) tall with the tallest known tree reaching 105 feet (33.5 m) and spread 102 feet (32.5 m) in Franklin Township, NJ. Generally, the swamp white oak is a durable and long – lived tree, but it is susceptible to numerous potential diseases and insect pests however, none are serious. Chlorosis or yellowing of the leaves while the veins remain green, often occurs when soils are alkaline and have a pH above 7.2.
Young plants from containers, young B&B trees and bare – root transplants are best installed in early spring at a young age. Transplanting this tree may be difficult because of the strong and rapid development of the taproot. Acorns planted in autumn at permanent positions give the best results. Then Quercus bicolor develops a double layer root system which allows it to grow well in areas that are flooded in spring but markedly dry in summer.
The swamp white oak develops a strong, upright trunk with distinctly dark gray exfoliating bark that is scaly, often peeling off in large, ragged, papery curls. It forms hybrids with bur oak where they occur together in the wild.
The bi–colored leaves are shiny dark green above and velvety white pubescence underneath, and are not like most oaks. Instead they are shaped like a broad, heavily toothed oval, approximately 5 – 7“(12–18 cm) long and 3 – 4 inches (7–11 cm) wide. In autumn, they turn brown, yellow – brown, or sometimes reddish, but generally, the color is not as reliable as other trees.
Very small, almost insignificant flowers are found on separate male and female catkins on the same tree in spring. The fruits are acorns which mature in early autumn. The light brown acorn is a half to one inch (1.5 – 2 cm) long and a half to three quarters inch (1–2 cm) wide. The acorn matures about 6 months after pollination. Seed production in swamp white oak begins at 20–30 years of age. The greatest production occurs between 75–100 years of age. Good seed crops are produced every 3–5 years.
The acorns are sweet and are an important food for wildlife such as squirrels, mice, white tailed deer, beaver, black bear, and a variety of birds, including ducks and turkey. Native Americans and pioneers ate the acorns raw or cooked. They have been ground into a powder and used as a thickening in stews or mixed with cereals for making bread. Roasted acorns have been ground and used as a coffee substitute. Bitterness of the tannins is removed by leaching in running water.
The Tales
Quercus bicolor is often planted on highway rights–of–way and is frequently used as a shade tree for large lawns, golf courses, parks, and naturalized areas. Because of this and it not having any serious pest issues and very few maintenance concerns, this oak was selected by the Society of Municipal Arborists as its Urban Tree of the Year in 1998.
Forests of elm, ash, and cottonwood will evolve to become oak dominated forests that include this oak. Then oak forests will evolve to become hickory and beech forests.
The swamp white oak is one of the more important trees that provide high quality lumber. The wood of swamp white oak is light brown, close – grained, heavy, and hard. It is similar to that of white oak (Q. alba) and usually is cut and sold under white oak name. However, the lateral branches of swamp white oak tend to persist so the wood is knotty and less valuable. The wood is used for furniture, cabinets, veneers, interior finishing, and flooring, as well as for boxes, crates, fence posts, railroad ties, and beams and boards for general construction. As with white oak, the wood provides tight cooperage and was once widely used in making barrels and kegs. Oak galls, caused by the activity of the larvae of various insects, can be used as a source of tannin and dye. They also are strongly astringent and can be used in the treatment of hemorrhages, chronic diarrhea, and dysentery. Some Native Americans used swamp white oak to treat cholera, broken bones, and consumption. Mulch from the dead leaves is reported to repel slugs, grubs, and various insects.
Quercus bicolor is used in large formal landscapes and was selected to be the featured tree in the 9/11 memorial landscape in New York City. It has also become a very popular parent in many new oak hybrids currently appearing in nurseries.
Wildlife such as deer, ducks, and geese, as well as other animals, are attracted to this tree for cover and when the acorns are dropping in autumn.
Quercus bicolor American Dream 'JFS – KW12' is a cultivar that is upright and becoming broadly pyramidal with age. This tree has deep green glossy leaves and greatly improved resistance to common diseases. It is especially good in heat and drought. The selection of this tree began in 1998 at a nursery in Oregon. For the next seven years, Keith Warrren examined over 10,000 Swamp white oak seedlings selecting 66 trees with superior features. They were identified, selected and transplanted for further study. Eventually 18 trees were chosen for further evaluation. In 2002 one tree was identified for its vigorous growth habit, its large deep green glossy leaves, and its excellent branch structure as well as its resistance to powdery mildew and oak anthracnose. In 2009, the stock was greatly increased. The decision was made to introduce this tree in 2012. Today, American Dream 'JFS – KW12', is receiving plaudits nationwide.
Appreciate the Swamp White Oak for its ability to grow well in our cities, have no serious pest problems, very few maintenance issues, and its unique 2–layer root system to tolerate problem soils.
Sources
- Dirr, Michael A. and Keith S. Warren, “The Tree Book”, Timber Press, 2019.
- Gilman, Edward F. and Dennis G. Watson, “Swamp White Oak”, US Forest Service, Fact Sheet ST – 278, November 1993
- J. Frank Schmidt & Son Fact Sheet
- Learn 2 Grow, Quercus bicolor, Plant Search, 2017.
- Missouri Botanical Garden, Quercus bicolor, 2017.
- Phillips, Leonard, “Swamp White Oak”, City Trees, The Journal of The Society of Municipal Arborists. Vol. 34, No. 1, January/February 1998.
- Wikipedia, Quercus bicolor, August 7, 2017.
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, Utility, Municipal Specialist, Tree Worker/Climber, Tree Worker/Aerial Lift, or BCMA science credits.
California UFC members will receive credit for passing the test. Please add your CaUFC number after your ISA and/or SAF certification number.
ASCA members may submit your ISA certification record to the ASCA and receive credits one for one.
MTOA members must follow the ISA instructions indicated above.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment online securely with your credit card or Pay Pal account. After your payment is submitted, click on ‘Return to Merchant' / gibneyCE.com. That will take you to the test sign in page followed by the test. Members with certifications from both ISA and SAF, please be sure to add both of your certification numbers. These numbers are important for reporting purposes.
To take the test as an annual subscriber with reduced rates, click on Password and enter your test password which will take you to the test sign in page. If you would like to become a subscriber see our Annual Subscription page for details.
When you have finished answering all questions you will be prompted to click ‘next’ to send your answers to gibneyCE.com. You can then click ‘next’ to view your test summary. A test review of your answers is available upon request.
All passing test scores are sent from gibneyCE.com to your organization(s) at the end of every month and they will appear on your certification record 4 to 6 weeks* after that. ISA maintains a record of CEU credits on their website.
*SAF requires 5 passing test scores before reporting.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option. You can spend as much time as you would like to take the test but it is important not to leave the test site until you have answered all the questions and see the 'sending your answers' response.