During the last century, eastern North America (ENA) has functionally lost two major tree species (American chestnut and American elm), two more, eastern and Carolina hemlock, will be functionally extinct over much of their ranges within ten years. This is a great loss for ecological diversity and paleoecological studies in ENA. Hemlock species are a keystone/foundation species found throughout ENA, but the invasive pest hemlock woolly adelgid (HWA) is causing rapid decline and mortality in a large portion of hemlock's range, especially in the southern Appalachian Mountains. Hemlock is approaching functional extinction in our region. Hemlock are one of the longest-lived tree genera in ENA and are sensitive to climatic variation and ecosystem disturbance, making them ideal species for the reconstruction of environmental history.
Unlike American chestnut, we have the opportunity to salvage environmental histories from hemlock species before they are lost. The proposed study will collect, analyze, and archive tree-ring samples from Carolina hemlock in western North Carolina. Results from this study would advance our understanding of disturbance regimes in eastern deciduous forests, elucidate recent changes in species composition and structure, and establish the Carolina hemlock response to climatic changes on a regional spatial scale.