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The Forest Dynamics Lab
| Research projects in my lab focus on the ecology and dynamics of mixed species forests. Projects under active investigation include:
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Disturbance history of a seasonal tropical forest in western Thailand
Supported by the Center for Tropical Forest Science of the Smithsonian Institute, the Arnold Arboretum of Harvard University, and the National Science Foundation (USA).
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- Student research projects in the Forest Dynamics Lab
The Forest Dynamics lab has a growing group of students doing Honours theses and independent study projects on a wide range of cool topics.
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The role of disturbance and history on the long-term dynamics of tropical forests is poorly understood. Unraveling the impacts of historical disturbances and the subsequent stand development patterns in tropical forests has been hampered by the lack of annual growth rings in most tropical tree species. In the seasonal tropical forests of Southeast Asia, however, intra-annual rainfall variation associated with the annual monsoons leads to the formation of annual growth rings in a number of tree species. I have been using dendroecological techniques developed in temperate forests to reconstruct the historical disturbance regimes of seasonal dry evergreen and mixed deciduous forest types in western Thailand at the Huai Kha Khaeng Wildlife Sanctuary. This work will provide insights into temporal patterns of establishment, growth, and mortality in seasonal tropical forests at the stand scale, as well as expanding our understanding of how disturbance and climatic fluctuations in recent decades and centuries have influenced the spatial distribution of several distinct forest types interspersed in mosaic fashion across the landscape.
Relevant publications:
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Baker, P. J., and S. Bunyavejchewin. Suppression, release, and canopy recruitment patterns in a seasonal tropical forest in western Thailand. (In prep)
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Baker, P. J., S. Bunyavejchewin, C. D. Oliver, and P. S. Ashton. Disturbance history and historical stand dynamics of a seasonal tropical forest in western Thailand. Ecological Monographs (accepted with minor revisions 9/04)
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Baker, P. J., and J. S. Wilson. 2003. Coexistence and relative abundance in forest trees. Nature 422: 581–582.
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Despite the great potential of dendrochronological studies to enrich our knowledge of past climatic variation, there are few such studies from Australia. Those studies that have been conducted in Australia are largely limited to a tree species from montane and sub-montane forests in Tasmania (e.g., Cook et al. 2000). Australia has thousands of native tree species, many of which grow in highly seasonal environments and may well exhibit annual growth patterns. Previous attempts to assess the dendrochronological potential of continental Australian trees have been limited to a small number of species from a small number of genera (primarily Eucalyptus and Callitris) from a small number of study sites (Ogden 1981). The sole study to examine a large number of Australian trees focused on species from the arid south (Schweingruber 1992), where multi-year droughts typically overshadowed seasonal climate patterns. There has been no concerted effort to systematically examine the majority of Australian tree species. Consequently, the dendrochronological potential of 99% of Australia’s diverse tree flora is unknown.
During 2005 I will be conducting a broad survey of the Australian tree flora to identify tree species with dendrochronological potential. This represents a necessary and major step forward in developing the critical foundations for future tree ring studies on forest and climate dynamics in Australia. The results will be of direct relevance to climatologists, conservation biologists, foresters, and paleaoecologists.
Background information:
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Cook, ER, BM Buckley, RD D’Arrigo, MD Peterson. 2000. Warm-season temperatures since 1600 BC reconstructed from Tasmanian tree rings and their relationship to large-scale sea surface temperature anomalies. Climate Dynamics 16: 79-91.
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Ogden, J. 1981. Dendrochronological studies and the determination of tree ages in the Australian tropics. Journal of Biogeography 8: 405-420.
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Schweingruber, FH. 1992. Annual growth rings and growth zones in woody plants of southern Australia. IAWA Bulletin 13: 359-379.
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More applied research has focused on developing sustainable silvicultural practices for Acacia koa, an ecologically and economically important tree species unique to the Hawaiian Islands. In partnership with the USDA Forest Service and The Nature Conservancy of Hawaii, my colleagues and I have been synthesizing basic silvicultural and ecological data and establishing long-term thinning and reforestation trials. Our research on koa includes individual tree monitoring, stand-scale silvicultural manipulations, and landscape scale modeling exercises. The goal is to provide Hawaiian landowners with science-based silvicultural options that effectively link high-quality conservation with sustained economic returns. By demonstrating that sound forest management is both economically and ecologically rewarding it will be now be feasible to stem the conversion of privately held forested lands to suburban development and pastures, thereby achieving landscape-scale conservation for forests that support one-third of the threatened and endangered species of the United States.
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