The Forest Sector in a Climate-Changed Environment—A Briefing

Across the globe and in the U.S., it is anticipated that forest resources in rural and urban settings will be affected by climate-change induced impacts to forest growing conditions, including CO 2 fertilization and disturbance regimes. These changing forest conditions are projected to trace through to changes in management regimes, production practices, and, potentially, the uses of timberlands within the forest products sector. In this paper, we report the results of studies that have used economic models to trace changes in forest growth as result of climate change to changes in behavior within the forest products sector. We also provide a discussion of the importance of urban forests, some potential impacts to urban forests from increased disturbance as result of climate change, and associated research needs. In the studies considered here (and in the current reports from the Intergovernmental Panel on Climate Change), forest productivity, globally and across the U.S., is projected to increase in aggregate under climate change. In the U.S., growth increases are projected to be fairly small (e.g., 1 to 3 percent per decade relative to the baseline), with increases generally projected for the North and West regions in most climate scenarios. Forest growth in the South is projected to decline in several climate scenarios because of projected limited water availability in an increased temperature environment. Although growth is projected to increase in aggregate, dieback of existing trees, increased disturbance in the U.S. South and West, and shifts in the location of some forest types are also projected to in many studies. 2 Under climate change, and when forest yields increase, timber harvest rotations in the U.S. are projected to increase slightly in the coming decades compared to baseline projections. When forest yields decrease, such as is projected in some scenarios for the southern U.S., timber rotations are projected to shorten. Timber rotations may also shorten if producers become concerned that the risk from dieback or disturbance is too great. Concurrent to an increase in timber rotation length, timber harvest volumes are projected to increase in aggregate. Globally, the greatest increases are projected for the lower Mid-latitude forests. In the U.S., slight increases in timber harvest are projected in most regions, with the West projected to have the greatest increases in one study. Under a lower emissions/lower temperature scenario considered in one study, timber harvests were reduced in the U.S. South. Harvests in Canada are projected to …