| Global policies, such as the Kyoto Protocol, are being developed to mitigate human influence on global biogeochemical cycles. Although the carbon cycle is currently at the core of these policies, the processes and geographic distribution of terrestrial carbon sinks remain unknown. For example, the northeastern United States is a possible location of a large carbon sink, but recent research indicates that there is decreasing land in forests, which may lead to decreasing carbon storage. The goal of this research is to quantify how recent land-use/land-cover change affects the spatial and temporal dimensions of carbon storage in the Northeast. To this end, this research uses a simple model to combine land-use/land-cover estimates on an ecoregion scale with biometric estimates of carbon from site-specific studies. The land-use/land-cover estimates were derived from satellite imagery from 1973 to 2000, whereas the biometric carbon estimates were geographically relevant to the study sites.; The model estimated total ecoregion carbon for two study sites in the Northeast—the North Central Appalachians and the Northern Piedmont. The total ecoregion carbon estimates showed that the potential Northeast carbon sink may be saturating. In the North Central Appalachians, there was a slight decrease in carbon storage throughout the 28-year study period. This loss was mainly due to the timber harvest rotation, when aboveground biomass was removed and replaced by young forests. In contrast, the Northern Piedmont increased carbon storage from the early 1970s through the early 1990s, when urban expansion led to carbon loss. Although these trends are contrary to other estimates of carbon in the Northeast, the carbon storage estimates agree with current research, thereby implying that these new trends only became evident because of the increased spatial and temporal resolution of the land-use/land-cover data used in this research. The results suggest that to understand the distribution of carbon sources and sinks, and therefore to develop sound carbon management policies, it is necessary to account for differences in land-use/land-cover change at regional and sub-regional scales. |
