Long-term Research

long-term vegetation research
The Pacific Northwest Permanent Sample Plot Program (PSP) is a long-term study of forest vegetation across the Pacific Northwest. Some of the plots have been sampled for 60 years and offer invaluable information on tree growth and mortality. 

Our understanding of the forested ecosystem at the HJ Andrews Experimental Forest is the product of decades of research. Funding for our long-term research comes from the US Forest Service's Pacific Northwest Research Station and from grants from the National Science Foundation's (NSF) Long-Term Ecological Research program.

The NSF has funded the Andrews Forest program through seven six-year grant cycles. The first two cycles, LTER1–2, focused on establishing long-term measurements and understanding fundamental ecosystem structure and processes related to old-growth forests, streams, and effects of logging on watersheds. Since LTER3, research at the site has been guided by a central question: How do land-use, natural disturbances, and climate change affect three key ecosystem properties: carbon and nutrient dynamics, biodiversity, and hydrology? Subsequent LTER cycles have continued to examine this question and have adopted specific scientific themes: LTER3—process-based understanding of landscape dynamics; LTER4—effects of early succession on ecosystem dynamics and the impact of species attributes on ecosystem dynamics; LTER5—synchronous temporal behaviors and drivers of biogeochemical cycling in small watersheds; LTER6—complex topography and its influence on interactions between drivers and ecosystem responders; and LTER7—connectivity between spatially variable flows of air, water, nutrients, organisms, and the expression of regional and global climate change and land-use in mountain ecosystems. In our current funding cycle, LTER8, we have three goals: To understand how disturbance legacies interact with environmental change to influence ecosystems; to understand how species interactions influence population and community responses to environmental change; and to evaluate how interactions of science, values, and ecological conditions influence land use decisions.

Past LTER-NSF grant proposals (PDF documents):