PARENT SESSION
Oral Session #55: Fire Ecology. Presiding: M. Moritz.
Wednesday, August 8, 2001. 1:00 PM to 5:00 PM. Hall of Ideas H.

Interactions of climate, land use, and carbon in Greater Yellowstone Ecosystem.

Graumlich, Lisa¹, Littell, Jeremy¹, Hansen, Andrew¹, ¹

ABSTRACT- Change in forest ecosystems can be rapid when strong feedbacks occur between biophysical drivers and management policies. Forests in the western United States are particularly prone to rapid change when strong physical constraints combine with pervasive human influence. For example, over the last century most lower elevation forests in the western United States have experienced significant changes in structure driven by interactions between climate and land use with important consequences for current assessments of national carbon sources and sinks. In particular, woody species encroachment into non-forest communities and infilling in forests subject to fire exclusion has resulted in a carbon sink of poorly specified dimensions. Using the Greater Yellowstone Ecosystem (GYE) as a prototype, we are developing data and analytic tools to understand past and to project future rates of carbon sequestration in Western forests as simultaneously influenced by climatic variation and land-use change. Over the last 200+ years, shifts in land-use policies and practices have driven changes in the structure and productivity of lower elevation forests. At finer temporal scales, shifts in precipitation regimes alter forest population processes and disturbance regimes.

KEY WORDS: fire, carbon, land-use