To learn about arboricultural issues of current interest in Southern California, click on a link below:
What about global warming and trees?
Sudden oak death
Bark beetles, drought and fire
Eucalyptus trees and red gum lerp psyllidOld Glory (the oak tree in Santa Clarita)
Trees and energy conservation
Opportunities for education
Please note: We are not affiliated with any organization listed in this website. We do, however, share a common professional interest in educating the general public about trees.
What about global warming and trees?
One of the most pressing issues in the news these days is global warming. It is an important issue, and trees play a role in it, but it may not always be clear exactly what that role is. We offer a simple discussion below for those who are interested in understanding more about the subject.
Global warming is probably a natural occurrence to some extent, and some people would have us believe that that is all that it is. Most scientists, however, think that we are contributing to global warming through our activities, and that we are accelerating the rate at which global warming occurs. The “greenhouse effect” is widely believed to be a major factor in global warming. So-called greenhouse gases such as water vapor, carbon dioxide, and methane, allow sunlight to pass through them and warm the earth. As the earth’s surface warms, energy is radiated back into space in the form of heat. Because this radiant heat has a longer wavelength, some heat is absorbed by greenhouse gases in the atmosphere and reradiated back toward the earth causing additional warming of the earth’s surface. As the concentration of greenhouse gasses in the atmosphere increases, the warming effect increases.
One greenhouse gas that is increasing in the atmosphere is carbon dioxide. Internal combustion engines used in most cars produce carbon dioxide (CO2), and contribute significantly to the gain in CO2. But there are also many other sources of carbon dioxide. Aircraft engines, coal-burning electricity-generating plants, home fireplaces, small engines, and forest fires also contribute to the release of CO2 into the atmosphere. All of these processes have a commonality. They are all burning carbon-based materials (gasoline, jet fuel, coal, wood) in oxygen and releasing energy, along with CO2 and various other byproducts. Other sources of greenhouse gases include thawing tundra (frozen tundra decays when it warms and thaws releasing CO2), livestock farming (methane, CO2), and vented landfill emissions (methane, CO2).
The carbon that is released in the burning of fossil fuels, wood, and wood products is the same carbon that can be “sequestered” by the growing of trees and plants. When a plant grows, it combines CO2 with water, using solar energy (photosynthesis), creating complex hydrocarbons (glucose, wood, etc), and releasing oxygen into the atmosphere. So, in effect, sequestration is the capture and storing of carbon atoms in the production of living tissues.
When trees die and fall to the ground, they usually decay within a few years to decades, releasing CO2 slowly back into the atmosphere. By contrast, when a forest fire occurs, or when forested land is cleared and burned for agriculture, huge quantities of CO2 are released into the atmosphere very quickly. Removing a single tree and turning it into firewood will have a similar rapid conversion, although on a much smaller scale. Under the right conditions, trees in a forest or jungle may become buried or submerged and eventually converted into crude oil and/or coal. That process takes millions of years, but that is where the carbon in our fossil fuels came from.
Trees are one of the best carbon sequestration vehicles, since they are large, long lived, and decay slowly when they die. The more trees that are growing on the planet, the less free carbon there is likely to be in the atmosphere. Think about that when you consider removing a tree. We do!
Sudden oak death
Sudden oak death (SOD) is a disease found in coastal California forest communities, caused by a fungus-like pathogen. At present, the disease has proved fatal only to certain species (tanoak, coast live oak, Shreve oak, and black oak), usually by causing cankers on the trunk of an infected tree. On many other types of plants, SOD is a foliar disease, causing leaf spots and dieback of twigs and branches. The disease cannot yet be definitively diagnosed in the field (without the use of laboratory tests).
Although SOD is considered an epidemic in Northern and Central California, it has not yet been identified in oak trees in Southern California. The most immediate source for up-to-date information on Sudden Oak Death (including how recreational users can prevent the spread of SOD) is the California Oak Mortality Task Force.
Bark beetles, drought and fire
Several species of pine trees in Southern California's San Bernardino Mountains, weakened by many years of drought, have succumbed to damage from Western, Mountain and Jeffrey pine bark beetles. While many dead trees have been salvaged and used for lumber, thousands of other trees were consumed by the fire in late 2003.
For more information, visit the Mountain Area Safety Taskforce (MAST) or the State of California Department of Forestry and Fire Protection.
Eucalyptus trees and red gum lerp psyllid
The red gum lerp psyllid is an insect pest of red gum eucalyptus trees, which now occurs throughout California. Psyllids cause defoliation and subsequent weakening of eucalyptus trees, and create a nuisance by excreting sticky honeydew which drops from affected trees.
The biological control program launched in 1999 to control the red gum lerp psyllid seems to be enjoying some success. Many defoliated trees that had appeared to be near death are now putting out new growth, and may be recovering. To learn more about the red gum lerp psyllid and the continuing research being done, visit the Los Angeles County Agricultural Commissioner.
Old Glory
This section is being updated. Please check back soon.
Trees and energy conservation
In Southern California, the need to conserve energy is more critical today than ever. With careful planning, trees can effectively be planted to reduce energy needs on both residential and commercial properties. Learn more about the benefits of the Urban Forest.
In Los Angeles, the Department of Water and Power has a program called Trees for a Green LA (click on "Program Advantages" to see a description of tree planting benefits).
Opportunities for education
To learn more about trees, arboriculture and urban forestry, visit the following websites:
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