LA Course #GCE-1-2101
Butterfly Decline, Forest Decline & Tree Longevity
Sections Go directly to the Section by clicking on the title below
Butterfly Decline, Forest Decline & Tree Longevity
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.
Where are the Butterflies?
Edited by Len Phillips
Are you aware of the alarming decline in the number of ladybugs, moths, bees, butterflies and beetles in your city over the last 30 years? Even songbirds are declining in number within the city landscape. Approximately 80% of all growing plants are angiosperms that require pollination from either bees, butterflies, or the other pollinating insects mentioned above. Without these pollinators, most plant life requiring insect pollination will disappear from our cities.
As urban foresters, landscape architects, gardeners and other nature lovers seeking to promote the well-being of the trees in our cities, we must also work to improve habitats for the pollinators who improve the quality of our urban environment. By making conscious decisions to design urban ecosystems that function as bio-filters, we can ultimately make a difference by creating habitats for urban pollinators as well as reducing the atmospheric carbon dioxide trends, by making very careful tree selections.
Trees provide shelter for insects from the cold winter winds while the insects also use solar energy for passive heating in winter. In summer, trees encourage the prevailing winds to provide a cooling mechanism, creating shelter and shade from unwanted solar gain.
We need to install trees that not only provide habitats for insects but also provide the benefits of cooling our cities in summer. Some trees that meet both these goals include the following:
Sources
Where are the Butterflies?
Edited by Len Phillips
Are you aware of the alarming decline in the number of ladybugs, moths, bees, butterflies and beetles in your city over the last 30 years? Even songbirds are declining in number within the city landscape. Approximately 80% of all growing plants are angiosperms that require pollination from either bees, butterflies, or the other pollinating insects mentioned above. Without these pollinators, most plant life requiring insect pollination will disappear from our cities.
As urban foresters, landscape architects, gardeners and other nature lovers seeking to promote the well-being of the trees in our cities, we must also work to improve habitats for the pollinators who improve the quality of our urban environment. By making conscious decisions to design urban ecosystems that function as bio-filters, we can ultimately make a difference by creating habitats for urban pollinators as well as reducing the atmospheric carbon dioxide trends, by making very careful tree selections.
Trees provide shelter for insects from the cold winter winds while the insects also use solar energy for passive heating in winter. In summer, trees encourage the prevailing winds to provide a cooling mechanism, creating shelter and shade from unwanted solar gain.
We need to install trees that not only provide habitats for insects but also provide the benefits of cooling our cities in summer. Some trees that meet both these goals include the following:
- Oak (Quercus) trees are the quintessential wildlife plants. No other plant genus supports more species of butterflies and moths (Lepidoptera) than the oaks.
- Black and Pussy Willows (Salix) attract many moths and butterflies in search of early spring blooms.
- Native cherries (Prunus), such as Black Cherry and Common Chokecherry, provide not only cherries as food for birds, but leaves that feed many types of caterpillars, from the large and striking Cecropia Moth Hyalophora cecropia L. to the abundant Eastern Tent Caterpillar Malacosoma americanum. Cuckoos, orioles, and many other woodland birds feed on tent caterpillars, while gnat-catchers pull away some of the caterpillar nests' silk for their own cup nest liner.
- The peeling River Birch (Betula nigra) bark provides shelter to many invertebrates, while the leaves and catkins also attract lots of butterfly and moth species. Seeds and buds from these rather small, somewhat short-lived trees, attract birds and small mammals. The adaptable River Birch is one of the favorites for butterflies, as well as being an excellent city tree.
- Butterflies and other Insects come to dogwood (Cornus florida) flowers while birds are after the autumn berries. There are also eastern and western dogwood (Cornus nuttallii) species, and trees as well as many shrubs, including the lovely-in-all-seasons Red-twig Dogwood (Cornus sericea) shrub.
- Many holly (Ilex) trees and shrubs are evergreen, providing year-round shelter, nesting places, and berries that ripen in late autumn or into winter. Choose from trees such as American Holly (Ilex opaca) or the deciduous and thorn-less Winterberry (Ilex verticillata). Although birds love them, remember that holly berries are toxic to humans and pets.
- The elderberries (Sambucus canadensis) are considered shrubs that can be trained to be small trees. They provide abundant flowers for insects, along with summer berries beloved by people and birds alike. Elderberries are not tolerant of road salt, so they are best grown back from the edge of the street.
- In summer, birds flock to the fruits of red mulberry (Morus rubra), after the pollinating insects have crowded their spring flowers.
- Juniper, including red cedars produce berry-like fruits and year-round shelter for birds and insects. Eastern Red cedar (Juniperus virginiana) fruits are a staple for Cedar Waxwings.
- Viburnums grow in the forest understory, attract many bees and butterflies as well as other insects to their flowers and leaves. In spring, viburnums provide nesting areas for a wide variety of songbirds. In autumn they produce favored berries. The birds are especially attracted to the Arrowwood Viburnum (Viburnum dentatum).
- From flowers to fruits to nesting cover, the Amelanchier family offers small trees and shrubs that are among the most popular with insects and wildlife. There are many species, including the tree-sized Downy Serviceberry (Amelanchier arborea), for beauty and bird appeal.
- Blackberry and raspberry (Rubus sp.) bushes attract many insects. The thorns create brambles that provide cover and nesting places for birds, while producing berries in summer.
Sources
- Blackwell, Mark, “Where are the Butterflies” blog.
- Howard, Youth, American Bird Conservancy, ”Attract Birds, A Dozen Native Trees And Shrubs That Birds Love”, November 27, 2018
The Death of Our Forests
Edited by Len Phillips
America was not ready for the COVID pandemic and it is not ready for the next pandemic to strike our woodlands. Humans and trees both suffer during plagues. In the past 200 years, voracious insects and fungi have swept across North America with frightening regularity, first killing the American chestnut, then the American elm, the Eastern hemlock, and most recently, all of the ash. Each of those trees anchored natural ecosystems, human economies, and cultures. While climate change and wildfires grab the headlines, invasive species have proven to be a far greater threat to forest biodiversity in America. These plagues have also enhanced climate change. Research has found that rotting trees killed in the US by forest pests release carbon dioxide into the atmosphere just like wildfires.
As much as we were unprepared for the Corona virus that has killed thousands and thousands of people in the US and millions of people worldwide, we are not ready for the next tree pandemic either. However, tree plagues differ from human pandemics. On the plus side (from a tree’s perspective), insects and diseases are often specific to a genus, so except for wildfires, no plague or disaster has hit every tree at once. On the minus side, people can stay indoors and get immunized, but trees have to stand there and take it.
Similarity between Plagues
In many ways however, tree plagues are surprisingly similar to human plagues and treatments can help us manage both types of threats. Human and tree plagues move around the globe via travel and trade. Early explorers in the 15th century brought smallpox, measles and other viruses to the New World, killing a substantial number of native people. Diseases and viruses have been leaping oceans ever since. Columbus’s arrival also set in motion the transplantation of Asian, European and American flora, but also new plants with insects and diseases.
In the millions of years since the continents separated from what had been a larger land mass called Pangea, trees like chestnut and ash had diverged into distinct species that provided sustenance to specialized communities of insects and microorganisms. Trees evolved defensive chemicals as a sort of tree immune system to keep all the pests at manageable levels. That’s why, for example, white oak trees can sustain more than 500 caterpillar species while retaining enough leaves to feed the trees themselves.
The trans-ocean movement of tree species starting in the 1700's upended things. Occasionally, a pest landed on a tree similar enough to its host tree to be digestible, yet dissimilar enough that the tree lacked defenses against the pest. In the early 1950's, for example, woolly adelgids from Japan were discovered in the United States. The tiny insects found the sap of Eastern hemlocks delicious and began to multiply, decimating hemlock trees. By the time the problem was raising alarms in the 1970s, the outbreak was too large to be contained. It may be thousands of years before the hemlock regains the abundance it had a mere five decades ago.
Infestation Examples
The story of the hemlock infestation highlights a parallel to human pandemics. There is usually a lag between when tree plagues begin to take hold and when they become noticeable. Once established, they become extremely difficult to eradicate and can cause billions of dollars in damages and dead trees. In California, sudden oak death, a disease caused by a nonnative fungus-like pathogen, was first noticed in the 1990s. It has killed millions of trees and had devastating effects on coastal forests in California and Oregon.
Ash trees have been decimated by the emerald ash borer, an Asian beetle that first struck in suburban Detroit in the early 1990s. It has since killed hundreds of millions of trees and threatens the 16 known ash species native to the United States, plus the insect species that feed on the ash without harming the tree.
At the present time, the spotted lanternfly, native to East Asia arrived in Pennsylvania in 2014 and is demolishing orchards and vineyards at a cost of millions of dollars a year as it moves toward the west.
Solutions
Perhaps the most straightforward measure to address this problem would be to stop importing trees and plants. But that is unlikely to happen. The horticulture industry, which generated more than $4.5 billion in sales of nursery stock in 2019, according to the U.S. Agriculture Department, has long thrived on offering customers a profusion of plants from around the world. Regulators have instead developed risk-assessment protocols and banned or quarantined imports of some trees and woody plants known to harbor dangerous pests. These measures have helped, but not stopped the problem. Because pests usually specialize on a single plant genus, scientists recommend banning imports of close relatives of native trees. Recent innovations have given scientists even more precise tools to identify new insect or pathogen threats. By planting trees native to the United States and Europe in China, for example, researchers have discovered insects native to Asia that could do major damage to American or European trees. Similar experiments are underway to identify threats to Asian trees growing in the US.
Regulating live plants won’t be enough. The emerald ash borer and another destructive invader, the Asian long-horned beetle, hitchhiked to the United States not on live trees but on wooden packaging material used to move freight. The spotted lanternfly is thought to have arrived in egg form on landscaping stone. Regulators have responded by requiring wood packaging to be heat-treated or fumigated. Requiring shippers to use alternative packing materials could be an even more effective solution.
Inspections of incoming shipments for insects or diseases that could attack trees are not effective. Only a small fraction is inspected. Still, live insects are detected in an average of some 800 shipments annually, according to investigators. An unknown number however, do slip through.
Travelers also have a role to play, by being responsible consumers and transporters of plants. An entomologist at the Forest Service worries about pests hitchhiking on exotic plants carried on airplanes and in traveler's luggage, which is barely inspected. He is also concerned about the boom in e-commerce, which the COVID-19 pandemic has encouraged.
In recent years, a chorus of voices including ecologists and public health experts have called for preserving forests and trees to head off a host of ills, from urban heat stress to global climate change and human pandemics. Indeed, it has become clear that deforestation increases the chances that humans will be exposed to more dangerous pathogens.
But far less attention has gone to slowing the expanding tide of plagues that humans, global trade, weak regulatory systems and carelessness, have inflicted on trees. If we want forests to protect us, we first need to protect the forests.
Source
Edited by Len Phillips
America was not ready for the COVID pandemic and it is not ready for the next pandemic to strike our woodlands. Humans and trees both suffer during plagues. In the past 200 years, voracious insects and fungi have swept across North America with frightening regularity, first killing the American chestnut, then the American elm, the Eastern hemlock, and most recently, all of the ash. Each of those trees anchored natural ecosystems, human economies, and cultures. While climate change and wildfires grab the headlines, invasive species have proven to be a far greater threat to forest biodiversity in America. These plagues have also enhanced climate change. Research has found that rotting trees killed in the US by forest pests release carbon dioxide into the atmosphere just like wildfires.
As much as we were unprepared for the Corona virus that has killed thousands and thousands of people in the US and millions of people worldwide, we are not ready for the next tree pandemic either. However, tree plagues differ from human pandemics. On the plus side (from a tree’s perspective), insects and diseases are often specific to a genus, so except for wildfires, no plague or disaster has hit every tree at once. On the minus side, people can stay indoors and get immunized, but trees have to stand there and take it.
Similarity between Plagues
In many ways however, tree plagues are surprisingly similar to human plagues and treatments can help us manage both types of threats. Human and tree plagues move around the globe via travel and trade. Early explorers in the 15th century brought smallpox, measles and other viruses to the New World, killing a substantial number of native people. Diseases and viruses have been leaping oceans ever since. Columbus’s arrival also set in motion the transplantation of Asian, European and American flora, but also new plants with insects and diseases.
In the millions of years since the continents separated from what had been a larger land mass called Pangea, trees like chestnut and ash had diverged into distinct species that provided sustenance to specialized communities of insects and microorganisms. Trees evolved defensive chemicals as a sort of tree immune system to keep all the pests at manageable levels. That’s why, for example, white oak trees can sustain more than 500 caterpillar species while retaining enough leaves to feed the trees themselves.
The trans-ocean movement of tree species starting in the 1700's upended things. Occasionally, a pest landed on a tree similar enough to its host tree to be digestible, yet dissimilar enough that the tree lacked defenses against the pest. In the early 1950's, for example, woolly adelgids from Japan were discovered in the United States. The tiny insects found the sap of Eastern hemlocks delicious and began to multiply, decimating hemlock trees. By the time the problem was raising alarms in the 1970s, the outbreak was too large to be contained. It may be thousands of years before the hemlock regains the abundance it had a mere five decades ago.
Infestation Examples
The story of the hemlock infestation highlights a parallel to human pandemics. There is usually a lag between when tree plagues begin to take hold and when they become noticeable. Once established, they become extremely difficult to eradicate and can cause billions of dollars in damages and dead trees. In California, sudden oak death, a disease caused by a nonnative fungus-like pathogen, was first noticed in the 1990s. It has killed millions of trees and had devastating effects on coastal forests in California and Oregon.
Ash trees have been decimated by the emerald ash borer, an Asian beetle that first struck in suburban Detroit in the early 1990s. It has since killed hundreds of millions of trees and threatens the 16 known ash species native to the United States, plus the insect species that feed on the ash without harming the tree.
At the present time, the spotted lanternfly, native to East Asia arrived in Pennsylvania in 2014 and is demolishing orchards and vineyards at a cost of millions of dollars a year as it moves toward the west.
Solutions
Perhaps the most straightforward measure to address this problem would be to stop importing trees and plants. But that is unlikely to happen. The horticulture industry, which generated more than $4.5 billion in sales of nursery stock in 2019, according to the U.S. Agriculture Department, has long thrived on offering customers a profusion of plants from around the world. Regulators have instead developed risk-assessment protocols and banned or quarantined imports of some trees and woody plants known to harbor dangerous pests. These measures have helped, but not stopped the problem. Because pests usually specialize on a single plant genus, scientists recommend banning imports of close relatives of native trees. Recent innovations have given scientists even more precise tools to identify new insect or pathogen threats. By planting trees native to the United States and Europe in China, for example, researchers have discovered insects native to Asia that could do major damage to American or European trees. Similar experiments are underway to identify threats to Asian trees growing in the US.
Regulating live plants won’t be enough. The emerald ash borer and another destructive invader, the Asian long-horned beetle, hitchhiked to the United States not on live trees but on wooden packaging material used to move freight. The spotted lanternfly is thought to have arrived in egg form on landscaping stone. Regulators have responded by requiring wood packaging to be heat-treated or fumigated. Requiring shippers to use alternative packing materials could be an even more effective solution.
Inspections of incoming shipments for insects or diseases that could attack trees are not effective. Only a small fraction is inspected. Still, live insects are detected in an average of some 800 shipments annually, according to investigators. An unknown number however, do slip through.
Travelers also have a role to play, by being responsible consumers and transporters of plants. An entomologist at the Forest Service worries about pests hitchhiking on exotic plants carried on airplanes and in traveler's luggage, which is barely inspected. He is also concerned about the boom in e-commerce, which the COVID-19 pandemic has encouraged.
In recent years, a chorus of voices including ecologists and public health experts have called for preserving forests and trees to head off a host of ills, from urban heat stress to global climate change and human pandemics. Indeed, it has become clear that deforestation increases the chances that humans will be exposed to more dangerous pathogens.
But far less attention has gone to slowing the expanding tide of plagues that humans, global trade, weak regulatory systems and carelessness, have inflicted on trees. If we want forests to protect us, we first need to protect the forests.
Source
- Popkin, Gabriel, “Invasive Insects and Diseases Are Killing Our Forests”, New York Times, Feb. 7, 2021
What is the Secret to a Tree's Longevity?
By Len Phillips
Many of the Ginkgo biloba trees in China are confirmed to be more than 1,000 years old. By examining the ginkgo's genetics, scientists found that the ginkgo vascular cambium contains no program for senescence, or death but, the tree continues its program for making youthful defenses even after growing for hundreds of years. Older Ginkgo trees also produce just as many seeds and their leaves are just as resourceful as those of young trees. Though it has yet to be tested, the researchers believe other old trees may have a similar pattern of genetic programming.
Being modular organisms, every year a Ginkgo grows new wood, new roots, new leaves, and new sex organs. A person on the other hand is born with all of the reproductive parts in the body and at a certain point people just get old and die.
Although Ginkgos live for many, many years, they do age. The trees grow taller with the cell-generating region called the apical meristem, producing growth in height and width, with the growth of the vascular cambium. Over time, weather or other things prevent the apical meristem from forming and elongating, limiting a tree’s height, and each year, leaves die and fall off. But the cambium, contained within the tree’s trunk, remains intact and active. Sometimes Ginkgo trees may be reduced to just hollow stumps, but with the cambium intact, they can still produce leaves, stems, and flowers. Some trees even remain alive as stumps, and re-sprout years after the rest of the tree has died or been cut down.
The Ginkgo's secret is maintaining a healthy defense system and being a species that does not have a predetermined senescence or aging program. As Ginkgo trees age, they show no evidence of weakening their ability to defend themselves from stresses. Researchers in the US and China studied ginkgo trees aged 150 to 667, extracting tree-rings and analyzing cells, bark, leaves and seeds. They found both young and old trees produce anti-oxidants, anti-microbial chemicals, and plant hormones, that protect against drought and other environmental stressors. Genetic studies showed that genes related to aging did not automatically switch on at a certain point in time, as happens in other living organisms such as grasses, people and animals.
Another feature of the Ginkgo is that it is a monotypic species. These are trees that are the only species within their genus. However, the other monotypic trees do have a predetermined senescence program. Examples of these monotypic trees are: Cercidophyllum japonicum - Katsura tree, Cryptomeria japonica - Japanese cedar, Davidia involucrata - Dove tree, Eucommia - Hardy Rubber Tree, Fitzroya cupressoides - Alerce, Maclura - Osage Orange, Metasequoia glyptostroboides - Dawn redwood, Sequoia sempervirens - Coast redwood, Sequoiadendron giganteum - Giant Sequoia, and Wollemia nobilis - Wollemi pine. According to researchers, these trees existed before the last ice age, which wiped out their natural pests. However, all these trees are be believed to have a senescence program.
Thus, while a Ginkgo tree that has lived for centuries might appear dilapidated due to winter damage or lightning strikes, all the processes needed for healthy growth are still functioning. Researchers suspect the picture will be similar in other long-lived trees, such as the Giant Sequoia, which has wood packed with anti-microbial chemicals.
Apart from a consistent supply of food, light and water, the ability of the Ginkgo to live to a great age and large size is thought to be linked to several factors. These include a slow growth rate, cellular adaptations and relative protection from secondary influences such as pests, drought, development, diseases, climate extremes, catastrophic physical damage and logging operations.
Although Ginkgos live long, they also age. Weather can damage the apical meristem, limiting a tree’s height over time. Each year, leaves die and fall off. But the cambium, contained within the tree’s trunk, remains intact and active. Researchers found that cell division tends to slow down after the age of 200, but the cells are still viable. They generate defenses and carry water and nutrients so the tree grows and stays healthy. Essentially, trees like Ginkgo could live forever because they do not die of old age.
Although humans are quite different from trees, contemplating them serves some purpose. Peter Crane, an evolutionary biologist and author of “Ginkgo: The Tree that Time Forgot,” said contemplating long-lived trees might help us to see further into a future than many of us tend to look at. “It’s kind of a way of calibrating how quickly our world is changing and reminding us that we shouldn’t always be thinking in the short term.”
The Ginkgo tree has been growing on this planet for 200 million years. This really puts our own species and our own individual existence into a clear perspective. We may not be at the center of everything. The universe does not revolve around us. Humans have only been here for two to three million years. That ought to encourage us to look at the big picture as we think about our relationship with the natural world. If we continue to consume fossil fuels and spew out carbon dioxide, and global warming continues to heat the planet, it will soon be impossible for the human race to survive. But the Ginkgo tree will live on!
Sources
The test that follows contains 30 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
LA CES will award 1.0 PDH (HSW) credit for a passing grade. North Carolina Board of LA and New Jersey Board of Architects will award 1.0 credits for a passing grade.
The cost for taking this test is $20 per credit. If you purchase an annual subscription for 12 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report your passing test score to LA CES. If you are also ISA* certified we will report your passing score to ISA for no additional cost. Please be sure to add your ISA Certification number when you sign in. Tests with passing scores may be submitted only once to each organization.
*ISA has approved this course for .5 CEUs per section for a total of 1.5 CEUs.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment 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. If you are an ISA and/or CLARB member, please be sure to include your certification/member number(s) along with your LA license and ASLA numbers.
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. 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.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option.
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.
LA CES maintains a record of earned PDH credits on their website http://laces.asla.org/
ISA maintains a record of earned CEU credits on their website http://www.isa-arbor.com/
By Len Phillips
Many of the Ginkgo biloba trees in China are confirmed to be more than 1,000 years old. By examining the ginkgo's genetics, scientists found that the ginkgo vascular cambium contains no program for senescence, or death but, the tree continues its program for making youthful defenses even after growing for hundreds of years. Older Ginkgo trees also produce just as many seeds and their leaves are just as resourceful as those of young trees. Though it has yet to be tested, the researchers believe other old trees may have a similar pattern of genetic programming.
Being modular organisms, every year a Ginkgo grows new wood, new roots, new leaves, and new sex organs. A person on the other hand is born with all of the reproductive parts in the body and at a certain point people just get old and die.
Although Ginkgos live for many, many years, they do age. The trees grow taller with the cell-generating region called the apical meristem, producing growth in height and width, with the growth of the vascular cambium. Over time, weather or other things prevent the apical meristem from forming and elongating, limiting a tree’s height, and each year, leaves die and fall off. But the cambium, contained within the tree’s trunk, remains intact and active. Sometimes Ginkgo trees may be reduced to just hollow stumps, but with the cambium intact, they can still produce leaves, stems, and flowers. Some trees even remain alive as stumps, and re-sprout years after the rest of the tree has died or been cut down.
The Ginkgo's secret is maintaining a healthy defense system and being a species that does not have a predetermined senescence or aging program. As Ginkgo trees age, they show no evidence of weakening their ability to defend themselves from stresses. Researchers in the US and China studied ginkgo trees aged 150 to 667, extracting tree-rings and analyzing cells, bark, leaves and seeds. They found both young and old trees produce anti-oxidants, anti-microbial chemicals, and plant hormones, that protect against drought and other environmental stressors. Genetic studies showed that genes related to aging did not automatically switch on at a certain point in time, as happens in other living organisms such as grasses, people and animals.
Another feature of the Ginkgo is that it is a monotypic species. These are trees that are the only species within their genus. However, the other monotypic trees do have a predetermined senescence program. Examples of these monotypic trees are: Cercidophyllum japonicum - Katsura tree, Cryptomeria japonica - Japanese cedar, Davidia involucrata - Dove tree, Eucommia - Hardy Rubber Tree, Fitzroya cupressoides - Alerce, Maclura - Osage Orange, Metasequoia glyptostroboides - Dawn redwood, Sequoia sempervirens - Coast redwood, Sequoiadendron giganteum - Giant Sequoia, and Wollemia nobilis - Wollemi pine. According to researchers, these trees existed before the last ice age, which wiped out their natural pests. However, all these trees are be believed to have a senescence program.
Thus, while a Ginkgo tree that has lived for centuries might appear dilapidated due to winter damage or lightning strikes, all the processes needed for healthy growth are still functioning. Researchers suspect the picture will be similar in other long-lived trees, such as the Giant Sequoia, which has wood packed with anti-microbial chemicals.
Apart from a consistent supply of food, light and water, the ability of the Ginkgo to live to a great age and large size is thought to be linked to several factors. These include a slow growth rate, cellular adaptations and relative protection from secondary influences such as pests, drought, development, diseases, climate extremes, catastrophic physical damage and logging operations.
Although Ginkgos live long, they also age. Weather can damage the apical meristem, limiting a tree’s height over time. Each year, leaves die and fall off. But the cambium, contained within the tree’s trunk, remains intact and active. Researchers found that cell division tends to slow down after the age of 200, but the cells are still viable. They generate defenses and carry water and nutrients so the tree grows and stays healthy. Essentially, trees like Ginkgo could live forever because they do not die of old age.
Although humans are quite different from trees, contemplating them serves some purpose. Peter Crane, an evolutionary biologist and author of “Ginkgo: The Tree that Time Forgot,” said contemplating long-lived trees might help us to see further into a future than many of us tend to look at. “It’s kind of a way of calibrating how quickly our world is changing and reminding us that we shouldn’t always be thinking in the short term.”
The Ginkgo tree has been growing on this planet for 200 million years. This really puts our own species and our own individual existence into a clear perspective. We may not be at the center of everything. The universe does not revolve around us. Humans have only been here for two to three million years. That ought to encourage us to look at the big picture as we think about our relationship with the natural world. If we continue to consume fossil fuels and spew out carbon dioxide, and global warming continues to heat the planet, it will soon be impossible for the human race to survive. But the Ginkgo tree will live on!
Sources
- Crane, Peter, “Ginkgo: The Tree that Time Forgot”
- Koop, Fermin,“The secret behind Ginkgo biloba’s near-immortal lifespan”, Environment Issues, January 15, 2020.
The test that follows contains 30 questions. Before taking the test be sure you have read the article carefully. The passing grade is 80% on the entire test.
LA CES will award 1.0 PDH (HSW) credit for a passing grade. North Carolina Board of LA and New Jersey Board of Architects will award 1.0 credits for a passing grade.
The cost for taking this test is $20 per credit. If you purchase an annual subscription for 12 credits, the cost per credit is reduced by 50% (see Annual Subscription link below). We will report your passing test score to LA CES. If you are also ISA* certified we will report your passing score to ISA for no additional cost. Please be sure to add your ISA Certification number when you sign in. Tests with passing scores may be submitted only once to each organization.
*ISA has approved this course for .5 CEUs per section for a total of 1.5 CEUs.
To take the test by the pay per test option, click on the 'Pay Now' button below where you can send payment 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. If you are an ISA and/or CLARB member, please be sure to include your certification/member number(s) along with your LA license and ASLA numbers.
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. 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.
Test re-takes are allowed, however you will have to pay for the retake if you are using the pay per test option.
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.
LA CES maintains a record of earned PDH credits on their website http://laces.asla.org/
ISA maintains a record of earned CEU credits on their website http://www.isa-arbor.com/