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Using dendrometer and dendroclimatology data to predict the growth response of Douglas-fir to climate change in the Pacific Northwest, USA
Citation:
LEE, E., P. A. BEEDLOW, R. S. WASCHMANN, D. T. TINGEY, C. A. BURDICK, AND A. Tepley. Using dendrometer and dendroclimatology data to predict the growth response of Douglas-fir to climate change in the Pacific Northwest, USA. Presented at 8th North American Forest Ecology Workshop, Roanoke, VA, June 19 - 23, 2011.
Impact/Purpose:
Altered seasonal climate patterns towards hotter, drier summers through the 21st century resulting from global climate change could affect the growth of coniferous forests in the Pacific Northwest (PNW) region of North America.
Description:
Altered seasonal climate patterns towards hotter, drier summers through the 21st century resulting from global climate change could affect the growth of coniferous forests in the Pacific Northwest (PNW) region of North America. The seasonal effects of temperature, precipitation, and soil moisture on monthly and annual stem growth of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) were examined using monthly dendrometer data for the period 1998-2009 at four sites on the western slope of the Cascade Mountains in Oregon and new and existing annual tree-ring width data from the PNW. We used a time series regression modeling approach to develop the growth-climate relations using seasonal climate variables as predictors of monthly and annual bole growth. Monthly basal area increment was primarily influenced by temperature and water availability. Annual radial growth of Douglas-fir was influenced by early season temperatures in the current year and soil water availability in the current and previous years. The seasonal and annual growth response to temperature was nonlinear with a temperature optimum ranging between 17 and 24ºC depending upon soil moisture conditions. Early snowmelt and warm, dry summers are likely to cause decreases in growth of Doulas-fir over much of the PNW, especially east of the Cascade crest. In contrast, Douglas-fir may exhibit growth increases at some higher elevation sites where water availability is not a limiting factor and seasonal photosynthesis is limited by low growing-season temperature.