The leaking oil rig on the Gulf Coast is an opportunity to think about the current state of environmentalism. It reminds us that at the height of our commitment to environmentalism, beginning in the 1960s, the need for action was more evident. Events such as the burning Cuyahoga River in Ohio and the smog alerts in Los Angeles helped us to understand the urgency of cleaning up our water and air. We believe a top priority for environmentalism today should be climate change and how to combat it. And we aren’t any less committed to keeping our water free of poisons such as herbicides than we were after we read A Silent Spring in the 1960s. Because the effects of climate change and herbicides are slow and less visible than a burning river or murky air, the public is not giving them the attention they deserve. The Gallup Poll reported that the percentage of Americans who believe that global warming will “affect them or their way of life in their lifetime” peaked at 40% in 2008 and declined to 32% in 2010.
The environmental movement is now committed to native plant restorations requiring the use of herbicides and deforestation that releases carbon into our atmosphere contributing to climate change. They are actively opposing projects such as wind and solar farms that would reduce the sources of climate change. We think they have lost their way.
Although there is a range of opinions about the causes of climate change, we subscribe to the theory most scientists support, that greenhouse gases (GHG) are the primary cause. GHGs create a “ceiling” around the earth that prevents the escape of heat, making our air hotter than it would otherwise be, turning the earth into a “greenhouse,” so to speak.
Carbon Dioxide (CO2) is the predominant GHG and carbon is an element of CO2. As trees grow, they absorb carbon and store it throughout their lives. When they die, and as they decay they release their stored carbon back into the air as CO2. Therefore, when we destroy a tree, we are contributing to climate change by releasing CO2 and by permanently ending the tree’s ability to absorb CO2 in the future.
There are several factors in the extent to which plants and trees can remove CO2. One is the size of the plant or tree. Generally, the bigger the plant or tree, the more carbon it is capable of storing. Therefore, when we destroy a large tree, such as a eucalyptus, and “replace” it with grassland or shrubs, we have significantly reduced the ability of that vegetation to store carbon.
We frequently hear native plant advocates claim that all the trees they wish to destroy will be replaced by native trees. This claim is not true. The natural history of the Bay Areas informs us that trees are not a conspicuous feature of the native landscape, which was grassland, scrub, and brush. Trees were found only in the crevices of hills where they were sheltered from the wind and where the hills funneled water to them. When native trees have been planted by native plant advocates where they are not adapted to survive, they have died. According to one of its members, the Claremont Canyon Conservancy has planted 5,000 redwoods of which only 20% have survived.
The stage of growth of the tree is also a factor in its ability to store carbon. Generally, a tree that is actively growing and still in good health is storing carbon at a faster rate than a tree that is diseased or is near the end of its life. Therefore, the health and the future of the eucalyptus forest are of interest to us.
Frequently those advocating for the destruction of eucalypts tell us they are diseased, or dying, or “infested” with insects. None of these claims is true. The predominant species of eucalyptus in the Bay Area is the Blue Gum. It lives in Southern Australia, with a climate similar to ours, for 400-500 years (Eucalypt ecology, Williams & Woinarski, Cambridge University Press, 1997) and for 100-200 years in climates more arid than ours. Insect infestations are rare in our eucalypts because they were brought here as seeds, not as plants (The Eucalyptus, Doughty, 2000). In other words, their insect predators were not brought here with them.
The final fate of the carbon that has been sequestered during the life of a tree depends upon what is done with it when it is destroyed. If it is used to build a house or another object that will “live on,” some of its carbon is retained in that object until it decays. So, we have an interest in what is done with the eucalypts and other non-native trees and plants when they are destroyed. Those that are chipped and spread to decay on the forest floor release their carbon as they decay. This is the method used by the “vegetation management” projects of UC Berkeley.
The “mother-of-all” these destructive projects is the East Bay Regional Park District (EBRPD) project to destroy about 400,000 trees. EBRPD says that these trees will be “disposed of at a commercial recycling or composting facility (and not a landfill)…” In other words, these trees will release their carbon into the atmosphere as they decay.
Let’s visit one final canard before we move on, the claim of native plant advocates that if we don’t destroy all the trees, they will burn anyway, and release their sequestered carbon at that time. To put it another way, we are told that we must destroy them to save them from burning.
We have discussed the claim that non-natives are more flammable than natives on the page, FIRE!! The Cover Story. In short, there is no truth to this claim. The trunk of the eucalyptus—where most of its carbon is stored—is very fire resistant. The few fires that have occurred in the East Bay have not destroyed the eucalypts. There has never been a wildfire in the urban forest in San Francisco.
We are reminded of one of the speakers at the recent Board meeting of the East Bay Regional Park District. As a doctor, he urged the Board to consider that the “cure” their plan proposes is worse than the disease. His patients prefer to take their chances of testicular cancer rather than have healthy testicles removed. So, why would they want to destroy their healthy trees to avoid the remote possibility that they might burn in the future?
Deforestation and Climate Change
When climate change is discussed the focus is usually on transportation, such as cars. We should be conscious of the fact that global deforestation is actually a larger contributor of greenhouse gases than transportation. Deforestation is now a major contributor to climate change, representing about 20 percent of global carbon emissions. Emissions from transportation are responsible for 10% of GHG.
The conventional wisdom is also that deforestation is occurring only in tropical countries. In fact, the United States lost a larger percentage (6%) of its forests than any other country from 2000 to 2005. Despite that loss, forests in the United States are still responsible for reducing net flux of carbon into the atmosphere according to the EPA: “Forests accounted for approximately 84 percent of total 2008 net CO2 flux, urban trees accounted for 10 percent…The net forest sequestration in urban forests is a result of net tree growth and increased urban forest size.”
The preservation of our urban forest is essential to reduce greenhouse gas emissions that cause climate change. When we destroy our urban forest, the San Francisco Bay Area is not doing its fair share in our country’s effort to combat climate change.