There are a variety of opportunities in the United States to expand the area of trees and forests, and to improve their growth, that could have significant impact upon the annual uptake of atmospheric CO2. Work coordinated by the American Forestry Association has attempted to quantify those opportunities, and demonstrate what kinds of costs and benefits might result from an attempt to begin implementing them. The first section of the work, reported in this paper, has focused on the opportunities that are seldom thought of as regular forestry-planting trees on marginal crop and pasture lands, increasing windbreaks and shelterbelts, growing trees as a biomass energy source, and improving urban tree canopies and placements as an energy-conserving measure. The benefits from such work include thc C sequestered in the biomass and soils involved, as well as the carbon emission reductions achieved through energy conservation. These opportunities could add up to a total C impact per year in the range of 141 to 382 x 10(6)t-somewhere between 10 and 30% of the current net C emission from fossil fuel in the United States. Additional work is underway to quantity the opportunities inherent in improving the management of existing forestlands, through more traditional forestry. The results of that work will be available in late 1992.
