Tree growth is controlled by climate processes that occur over a range of temporal scales. Interannual (high-frequency) climate variation is an important process that influences tree growth on a short time scale. Longer term (low-frequency) climate trends have also been shown to influence tree growth over long periods, and may have implications regarding long-term forest productivity and adaptation to climate change. As well, research has shown that low-frequency quasi-periodic climate/ocean processes such as El Niņo Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) may influence tree productivity in certain habitats in western North America. It is important to elucidate the complex interactions between climate processes at various temporal scales and their impacts on tree growth and productivity in order to better understand the potential responses and adaptation of B.C.?s forests to climate change.
There is a current lack of knowledge regarding how the productivity of many commercial tree species in B.C. may be affected by climate change. This project addresses a specific knowledge gap regarding species-specific growth responses to low-frequency climate change in the B.C. Interior. The purpose of this research project is to complement and expand the research under FSP #Y071270 by examining how Douglas-fir productivity and climate-growth responses over the species? geographic and climatic range in the B.C. Interior may be affected by low-frequency climate trends and climate fluctuations such as PDO and ENSO. Specifically, this project seeks to identify possible regions or ecological conditions that may represent significant and dramatic changes in Douglas-fir productivity responses as a result of low-frequency climate change.
This study is unique from the project funded under FSP #Y071270, which described an ecological pattern of climate-related interannual growth variation in Douglas-fir, with a focus on examining potentially strong climate-growth relationships at the abiotic limits of the species. In FSP #Y071270 climate-growth relationships were examined over the full climate record (~1900 to present). The study proposed here will examine temporal patterns in climate-growth relationships embedded in the full climate record that may be related to low-frequency climate trends or oscillations such as PDO and ENSO. The proposed objectives represent an additional important aspect of tree productivity responses to climate change that will enhance the foundational information generated by FSP #Y071270.
Low-frequency climate trends and oscillations form the temporal focus of this proposed examination. Low-frequency climate trends are defined here as gradual and directional changes in temperature and precipitation that are occurring in the province over multiple decades; low-frequency climate oscillations are defined here as somewhat periodic climate fluctuations that can range from several years to several decades.
A directional climatic trend (increasing) in average and minimum monthly temperatures has been described in British Columbia over the past century, with a stronger increase in the northern half of the province. This trend is expected to continue; various climate-change models predict that mean annual temperatures in B.C. by 2100 could be 2-7 °C above the mean for the previous 1000 years. Long-term precipitation changes are also evident across the province, however, they show greater regional differentiation and are more difficult to predict. Directional changes in temperature and precipitation may cause tree growth to respond to climate in new and complex ways over periods of decades. A preliminary analysis of data collected under FSP #Y071270 has identified abrupt shifts in climate-growth relationship in Douglas-fir populations in at least some regions in British Columbia. For example, growth in northern populations of Douglas-fir was positively correlated to summer temperatures during ...
Green, D. Scott, Griesbauer, Hardy P.. 2009. Examining interactions between long-term climatic fluctuations and Douglas-fir productivity in the BC interior. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2009MR313
Topic: FLNRORD Research Program
Keywords: Forest, Investment, Account, (FIA), British, Columbia
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