In theory, burning biomass (any kind of plant material) to derive energy is a carbon-neutral endeavor, meaning that the carbon dioxide released during the process is in turn absorbed by other plants and put to use in photosynthesis and as such does not contribute to the greenhouse effect. Biomass is also flexible: It can be turned into ethanol to power up automobiles, or can be burned like coal to generate heat and/or electricity. Factor in that biomass feedstock is usually inexpensive, widely available and a seemingly perfect alternative to the carbon-spewing, foreign-derived fossil fuels we rely on so much these days.
Typically unmarketable trees, brush and logging debris becomes the feedstock for biomass processing plants or for coal-fired power plants equipped to co-fire with plant material. But environmentalists warn that some timber companies and their utility and state customers are taking things too far by levelling entire forests including some within publicly owned national forest land to generate more feedstock for otherwise underutilized biomass energy production facilities.
Among the negative environmental impacts, chopping down forests to burn for ethanol production even if replanted as tree plantations is like biting the hand that feeds you. "Natural forests, with their complex ecosystems, cannot be regrown like a crop of beans or lettuce - reports the non-profit Natural Resources Defense Council (NRDC), a leading environmental group. - And tree plantations will never provide the clean water, storm buffers, wildlife habitat, and other ecosystem services that natural forests do."
Another negative for biomass is that burning it, like coal or anything else, produces air pollution including sulfur dioxide, nitrogen oxides, particulate matter and a variety of toxic substances. According to NRDC, these pollutants increase the incidence of asthma, heart disease, lung cancer and other respiratory ailments, and premature death.
But perhaps most troubling about plans to cut down forests for biomass feedstock is taking carbon neutrality out of the equation, given the fact that tree loss in and of itself is already responsible for some 20 percent of the world s total carbon pollution. "When biomass is harvested from forests, carbon stored in the soil is released into the atmosphere, - reports NRDC - This is in addition to the carbon that is emitted when the wood is burned for energy. And there s no guarantee the lost trees will ever be replaced."
NRDC concedes that there is still a place for biomass in the alternative energy universe, but cautions that only biomass that is carefully chosen, grown responsibly, and efficiently converted into energy can reduce carbon and other emissions compared to fossil fuels."