The natural photosynthetic process that drives the growth of trees results in the storage of carbon largely in the form of cellulose and hemicellulose. As a result, forests have an important function in helping regulate the Earth's carbon cycle.
The capacity of our forests to sequester carbon suggests that optimized forest management and forest carbon storage can be an important and cost-effective tool in reducing carbon dioxide in the atmosphere. Forest carbon sequestration is at least as economical as improving energy efficiency, switching to renewable energy production, fuel switching, and capturing and storing carbon dioxide emissions.
The use of forest carbon sequestration as an effective atmospheric carbon-management strategy has not been widely adopted largely because it is difficult to measure and monitor the effectiveness of a given stand of trees. We do know that forests in the United States sequester about 13 percent of the anthropogenic carbon dioxide emitted annually. Of this sequestration, approximately 11.5 percent is achieved by our natural forests and 1.5 percent is achieved by our urban forests. We also know that a medium-sized tree in our northern forest sequesters approximately 48 pounds of carbon dioxide annually and, in the process, emits enough oxygen to sustain two human beings.
It has been suggested that the cost to the U.S. economy of lowering greenhouse gas emissions (GHG) could be reduced by 50 percent over the next several decades by including forest carbon sequestration in addition to direct emission reductions. The Intergovernmental Panel on Climate Change (IPCC) has estimated that the cost for sequestering carbon dioxide is in the range of $15 per ton. This compares well with unit costs from fuel switching and energy-efficiency costs per ton of abated carbon dioxide.
Estimates of global carbon stored by our forests range widely. The IPCC has estimated that we could sequester an additional 4 billion tons in our global forests over the 30-year period from 2020 to 2050. As a frame of reference, it has been estimated that in 2009 the carbon stored in forested land in the United States was about 800 million tons.
It is most obvious that in the absence of federal action on climate change there is not a strong incentive to both recognize and provide the structure and financial resources to expand the application of forest carbon sequestration. The one bright spot is the California Climate Policy that does recognize and include forest carbon sequestration as a management strategy.
There are several things we must do to make a difference:
•We need to develop a stronger methodology for modeling and measuring the carbon stored by our forests on both a local and international scale.
•We need to use sophisticated satellite remote-sensing capabilities to provide for both mapping and more accurate carbon storage.
•We need to complete the international estimates of climate negotiations and get about the process of reducing humankind's carbon footprint and use our forests to cut the costs of compliance.
In the process, we will protect biodiversity, increase habitat, better protect our water resources and improve the quality of life.