Observing and Understanding the Impacts of Climate on Alaskan Forests
Ecological Climatology of Alaskan Forests and Ecotones
Dates
Start Date
2013-06
End Date
2018-10
Release Date
2016
Summary
Changing climate conditions (e.g. changes to air temperature, surface temperature, snowpack duration, and soil temperature) are affecting where trees are able to successfully grow and are bringing changes to the structure of forests throughout many parts of Alaska. In order to understand and project future vegetation changes, scientists use computer models to establish the relationships between climate variables, such as those mentioned above, and ecological responses such as the presence or absence of a tree species, tree growth and establishment, changes in sap flow, and other demographic and physiological responses. These computer models, however, frequently do not account for Alaska’s extreme topography and climatic gradients, [...]
Summary
Changing climate conditions (e.g. changes to air temperature, surface temperature, snowpack duration, and soil temperature) are affecting where trees are able to successfully grow and are bringing changes to the structure of forests throughout many parts of Alaska. In order to understand and project future vegetation changes, scientists use computer models to establish the relationships between climate variables, such as those mentioned above, and ecological responses such as the presence or absence of a tree species, tree growth and establishment, changes in sap flow, and other demographic and physiological responses.
These computer models, however, frequently do not account for Alaska’s extreme topography and climatic gradients, and have often not been verified with direct observations due to availability of only a sparse observational network. Direct observations of tree responses to climate change are currently only available at a handful of sites such as at Caribou / Poker Creek and the Bonanza Creek Long Term Ecological Research facility.
This project aims to provide observations of climate and tree responses in order to better establish the direct effects of climate on ecological processes. The project team has established a network of forest and treeline observation sites in the wet, comparatively warm southeast Alaska perhumid rain forest, the transitional boreal forest in south central Alaska, and at the limits of tree distribution in the boreal forest and northwestern Alaska. The project will also contribute to the use of inexpensive temperature sensors in high-latitude environments and to synthesis assessments for the modeling of species distribution.
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GulkanaRiver_AK_MPD.jpg “Gulkana River, Alaska (public domain)”
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Purpose
Models built to project future vegetation changes given climate change frequently rely on gridded observed climate to establish the relationships between climate variables and ecological responses such as tree species’ presence/absence, tree growth, establishment, and other demographic and physiological responses. However, gridded historical climate in Alaska relies heavily on both a sparse network of observations and generalized assumptions about temperature lapse rates with elevation that do not account for Alaska’s extreme topography and climatic gradients. Much of what is known about tree responses from individual growth to species distributions therefore comes from assumed climatic relationships that have rarely, if ever, been verified with direct observation; such observations are only available at a handful of sites such as the Caribou/Poker Creek site and Bonanza Creek Long Term Ecological Research facility. We have established a network of forest and treeline sites from the wet, comparatively warm southeast Alaska perhumid rain forest, the transitional boreal forest in south central Alaska, and the limits of tree distribution in the boreal forest and northwestern Alaska. The aims of this project are to provide observations of climate (including, but not limited to air temperature, surface temperature and snowpack duration, soil temperature) and co-located ecological responses (including, but not limited to tree establishment, sap flux, and tree growth) in order to better establish the direct effects of climate on ecological processes than species/climate associations alone can. The project will also contribute to fundamental methodological development for the use of inexpensive temperature sensors in high-latitude environments and synthetic assessment of standard species distribution modeling.