Last modified 09/18/08
Ryan, M.G.; Archer, S.R; Birdsey, R.A.; Dahm, C. N.; Heath, L. S.; Hicke, J. A.; Hollinger, D. Y.; Huxman, T. E.; Okin, G. S.; Oren, R.; Randerson, J. T.; Schlesinger, W. H. 2008.
In Review. Land Resources. Pages 123-182. In: Janetos, T.; Schimel, D., eds. The Effects of Climate Change on Agriculture, Land Resources, Water Resources, and Biodiversity, SAP 4-3. US Climate Change Science Program, Washington, DC, USA. 362 pp.
This synthesis and assessment report builds on an extensive scientific literature and series of recent assessments of the historical and potential impacts of climate change and climate variability on managed and unmanaged ecosystems and their constituent biota and processes. It identifies changes in resource conditions that are now being observed and examines whether these changes can be attributed in whole or part to climate change. It also highlights changes in resource conditions that recent scientific studies suggest are most likely to occur in response to climate change, and when and where to look for these changes. As outlined in the Climate Change Science Program (CCSP) Synthesis and Assessment Product 4.3 (SAP 4.3) prospectus, this chapter will specifically address climate-related issues in forests and arid lands. In this chapter the focus is on the near-term future. In some cases, key results are reported out to 100 years to provide a larger context but the emphasis is on next 25-50 years. This nearer-term focus is chosen for two reasons. First, for many natural resources, planning and management activities already address these time scales through development of long-lived infrastructure, forest rotations, and other significant investments. Second, climate projections are relatively certain over the next few decades. Emission scenarios for the next few decades do not diverge from each other significantly because of the “inertia” of the energy system. Most projections of greenhouse gas emissions assume that it will take decades to make major changes in the energy infrastructure, and only begin to diverge rapidly after several decades have passed (30-50 years). Forests occur in all 50 states but are most common in the humid eastern United States, the West Coast, at higher elevations in the Interior West and Southwest, and along riparian corridors in the plains states (Figure 3.1) (Zhu and Evans 1994). Forested land occupies about 740 million acres, or about one-third of the United States. Forests in the eastern United States cover 380 million acres; most of this land (83 percent) is privately owned, and 74 percent is broadleaf forest. The 360 million acres of forest land in the western United States are 78 percent conifer forests, split between public (57 percent) and private ownership (USDA Forest Service and U.S. Geological Survey 2002).
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