This Long Term Ecological Research (LTER) project will examine controls over ecosystem structure and function in the boreal forest of interior Alaska. A combination of experiments and observations will be used to document the changing nature of ecosystem controls during primary succession on river floodplains and during post-fire secondary succession in the uplands. The central hypothesis of the project is that the pattern of succession is determined primarily by initial site character- istics and by the life history traits of component species and that the rate of successional change is then determined by vegetation-caused change in environment and ecosystem function. The following aspects will be emphasized: (1) vegetation change and demographic controls, (2) vegetation-caused changes in resources and standing crops of biomass and nutrients, (3) controls over nutrient supply, (4) the role of herbivores as consumers and modifiers of succession, and (5) the role of invertebrates and microbes as regulators of organic decomposition and nutrient remineralization processes. This new research project builds upon a past record of major research accomplishments and productivity stemming from the site upon which the new project will be based. New research themes are derived from past observations and experimental results spanning a period of more than a dozen years of work. The project will provide an integration of sound fundamental ecological research with opportunities to have substantial impact upon the stewardship and management of vast tracts of renewable natural resources. The primary research team and project leadership are of proven high quality in their own right, and the total effort will be further strengthened by the use of outside consulting expertise in certain specialty areas. Facilities provided by the University of Alaska are excellent. Additional facilities provided by the USDA/Forest Service will further enhance the work as will other support in kind from that source. It is reasonably expected that the output from this extreme of the forested environment will provide a valuable comparison base for other similar work being conducted on temperate forest ecosystems. In a similar fashion it is expected - and documented for its earliest phases - that this project will easily integrate itself into the network of similar ongoing projects in a major contributory role. The Ecosystem Studies Program recommends that funding be made available for the first year of this five-year continuing award.
