The Harvard Forest LTER program seeks to interpret ecological pattern and process in New England forests and to apply this knowledge to regional and global issues in forest conservation, land restoration and protection, public policy, and the environment. Over the past decade, HF LTER has matured into a collaboration that applies unique approaches in historical and community ecology, ecophysiology, atmospheric chemistry, and ecosystem studies to the interpretation of long-term, large-scale experiments and measurements, mechanistic studies, and retrospective research. In LTER I, we used primarily site-based annual and static measurements to interpret current conditions and to evaluate the comparative response of forest ecosystems to natural disturbance (hurricanes) versus anthropogenic stress (N deposition and soil warming). Long-term measurements from these studies enabled LTER II to associate inter-annual variation in processes and environment, to examine land-use impacts at site to sub-regional scales, and to incorporate an understanding of historical landscape transformations into interpretations of modern pattern and process. This research produced major accomplishments: > 300 publications; a synthesis volume linking 1000 years of forest dynamics to ecosystem structure, function, and composition; an annual Research Program for 35 students; and innovative approaches to regional, national, and international cross-site studies.

In LTER III we seek to make major advances in our understanding of the interactions among disturbance, environmental change, and ecosystem pattern and process at site to regional and even global scales. We propose to: (1) extend measurements, modeling activities, and historical studies to regional scales; (2) interpret landscape development, vegetation and wildlife dynamics, and ecosystem patterns in relationship to millennial-scale climate change, land-use, and disturbance; (3) evaluate ecosystem response to critical ongoing disturbances and stresses (e.g., forest cutting and conversion, ozone and N deposition, and invasions by pests and non-native plants); (4) interpret long-term measurements and responses to experimental treatments mechanistically and in relation to inter-annual and inter-decadal variation and history; and (5) apply these results to understanding the current and projected role of this region in global carbon storage. In these efforts we will (1) continue our long-term experiments and measurements; (2) strengthen our inter-disciplinary connections and cross-site comparisons; (3) add new mechanistic studies, disciplines, and co-investigators; and (4) leverage major additional support from NSF, DOE, NASA, EPA, USDA, The Nature Conservancy, and private foundations.