Dendrochronological Evidence of Extreme Events on the Gulf of Mexico Coast
Drought, flooding, and hurricane activity disrupt the human and natural landscape throughout the southeastern United States. Instrumental records through the past century suggest that the patterns of these extreme events are changing through time, especially in relation to rising global temperatures. However, instrumental records before the industrial revolution are rare, thus proxy records like tree rings are useful for comparing climatological conditions before massive human modification of the atmosphere. Tree-ring records are also useful as indicators of change to the natural landscape. The research in this presentation demonstrates three tree-ring proxy methods that can be used to extend long-term records of extreme events into the past: tree-ring width, wood anatomy, and chemical composition. These methods indicate that (1) long-term drought is present in tree-ring streamflow reconstructions, (2) intense flooding causes marked differences in wood anatomy in a single year of growth, and (3) hurricane activity, though nuanced, affects both chemical and physical processes of wood formation. As researchers continue to use these methods on old-growth trees, long-term event-based climatologies can describe millennial-length changes in the environment of the southeastern U.S.