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An Alternative View of the Climate Warming Mitigation Potential of U.S. Temperate Forests
Citation:
Wickham, J. An Alternative View of the Climate Warming Mitigation Potential of U.S. Temperate Forests. Southeast Division of Association of American Geographers, Athens, GA, November 23 - 25, 2014.
Impact/Purpose:
Demonstrate climate mitigation potential of forestation in U.S. at the SDAAG in Anthens GA 11/23-11/25/14
Description:
Many U.S. federal and non-governmental agencies promote forestation as a means to mitigate climate warming because of the carbon sequestration potential of forests. This biogeochemical-oriented carbon sequestration policy is somewhat inconsistent with a decade or more of research that suggests that temperate and higher latitude forests tend to be warmer than surrounding fields. The relative warmth of forests compared to surrounding fields suggests that deforestation at these latitudes would promote cooling. Those that criticize the biogeochemical-oriented forestation policy point out that biophysical factors (e.g., albedo, surface roughness, stomatal resistance) must also be considered in tandem with biogeochemical factors (carbon sequestration). We compared satellite-based surface temperature (MODIS) and satellite-based land cover (NLCD) to assess the relative warmth of U.S. forests as compared to surrounding fields. We found that: 1) forests tended to have lower surface temperatures than surrounding fields across the conterminous U.S. both annually and in all seasons except winter; 2) the inverse relationship between forest extent and surface temperature was scale dependent, with goodness-of-fit increasing as the measurement scale of forest extent increased, and; 3) south of approximately 36°N forests tended to be warmer than surrounding fields even in winter. Our results suggest that U.S. temperate forests tend to promote cooling and that deforestation would more likely lead to warming. Further, we have developed a land cover-albedo dataset because the low albedo of forests (relative to surrounding fields) tends to be the primary biophysical factor leading some to conclude that deforestation would promote cooling. The dataset includes 14 years of MODIS-based albedo data linked to areas of homogeneous land cover that can be used to compare albedo change as a function of land cover change.