Successional processes associated with wildfire and floodplains; facilitative and competitive interactions among plant species throughout succession; plant-mediated changes in resource and energy availability for decomposers; herbivorous control of plant species composition; hydrologic regime and stream ecology. Research is conducted at two primary research sites. Bonanza Creek Experimental Forest (BCEF), located approximately 20 km southwest of Fairbanks along the Parks Highway, focuses on ecosystem controls in forest succession. The Caribou-Poker Creeks Research Watershed (CPCRW) is a 10,400 ha upland research site 45 km north of Fairbanks. CPCRW is dedicated to research into hydrologic and environmental questions in the discontinuous-permafrost boreal forest of the Yukon-Tanana Uplands of central Alaska. Ecological research in the boreal forest is important because the boreal forest, one of the few remaining biomes with a largely natural disturbance regime, plays a critical role in determining the rate of global climate change. The principal objective of our current research program under LTER1 and LTER2 is to conduct a long-term study of ecosystem structure and function through examination of controls over successional processes in taiga forests of interior Alaska. The addition of CPCRW, expanded the research opportunities to include studies into basic ecosystem processes, forest succession, and hydrologic regime and stream ecology in a first-order to fifth-order stream-continuum. Our research under the LTER3 proposal will seek to understand the Alaskan boreal forest as an integrated regional system in which climate, disturbance regime, and ecosystem processes are interactive components. Our overall objective will be to document the major controls over these interactions and their ecological and societal consequences.