20th century climate and wildfire in the western U.S. Funding: Western Mountain Initiative and CIG (with D.McKenzie, D. L. Peterson, T. Westerling) Associations between modern climate and wildfire in the late 20th century were strong, but the strength of these relationships were unverified over much of the west prior to the 1970s. They also have not been well described ecologically, and there has been little attention paid to how different ecosystem vegetation types mediate fire climate relationships. In this study, we extended fire climate relationships back to 1916 and found that ecosystem vegetation played a strong role in the nature of the climate-fire relationships. These relationships paralleled what is known from tree-ring based fire history data. Fire history of lower elevation forests in the northern Greater Yellowstone Region - Funding: USDA NRI Seed Grant (with L.J. Graumlich) A dendrochronologically precise reconstruction of fire history has never been conducted in lower elevation Douglas-fir dominated forests of the Greater Yellowstone Ecosystem, and the climate-fire relationships remain poorly understood. This study used tree-ring records of fire between the 1580s and historical times and related them to independent reconstructions of precipitation and climatic variability. Growth-climate relationships for Douglas-fir along biophysical gradients - Funding: Western Mountain Initiative and CIG (with D. L. Peterson and M.T. Tjoelker) Study of the relationship between tree growth and climate is often restricted to those trees most useful for climate reconstruction; here we employ principles from landscape ecology, dendroecology, physical geography, and atmospheric sciences to try to understand the climatic controls on growth for Douglas-fir (Pseudotsuga menziesii) across its biophysical range. Biotic and climatic co-limitation of treeline establishment of conifers in mountain ecosystems of the western U.S. - Funding: US DOE National Institute for Climate Change Research (with N. Mantua, M. Germino, and L.J. Graumlich) Treeline environments - both the alpine/upper treeline and steppe/lower treeline ecotones are likely to be some of the most sensitive ecosystems to climate change (and multidecadal climate variability). However, biotic interactions, both between tree species and between trees and other vegetation, may mediate the relationship between climate and local population changes. In this study, we are using both experimental manipulation and detailed observational studies to better understand the climatic and ecological controls on treelines in nine western mountain ranges. Hydroclimate reconstructions for water resource managers in the Pacific Northwest - Funding: NOAA Sector Applications Research Program (with A. H. Hamlet, N. Mantua, and C. Woodhouse) Few hydroclimatic reconstructions exist in the Pacific Northwest, yet the future of water resources management is likely to need information on past variability in hydroclimate in order to project future regional and local water supply given changing climate impacts on water supply and population demand. We are using a unique combination of hydrological modeling and dendroclimatology to provide better reconstrucitons for water managers. This project will also solicit input form water resource managers to improve the utility of the reconstructions. Snow persistence, distribution, and the phenology of conifers in PNW National Parks Funding: North Cascades Research Learning Network (with J.D. Lundquist) Where should National Park Service resource managers monitor snowpack? How important is topographical variation to snowpack persistence? What consequences does this variation have for vegetation pheonology?