• Dendroclimatic Reconstruction from Bald Cypress in Southwestern Indiana

      Van De Veer, Robin Lyn (2011-09-20)
      In the United States, bald cypress (Taxodium distichum) is generally recognized as an important component of the forested wetlands found in the Southwestern Coastal Plain and the Mississippi River Valley (which extends to the southern Midwest). The lifespan of this deciduous species is important not only commercially, but also in an ecological capacity. This study focuses mainly upon the role the tree plays in its environment and how it can be used as an indicator of climate through drought/flood signals in the rings. Bald cypress is a long-lived tree that can be over 1000 years old and is sensitive to climate and ground water hydrology. Because of these factors it is a favorable choice for dendrochronological study in the region. According to the International Tree-Ring Database, a chronology of the species is not well defined for southwestern Indiana. This research provides this missing information and creates the northern most bald cypress chronology in the Midwest. The study site is located in the extreme southwest of Indiana around Hovey Lake (a backwater lake of the Ohio River) about 10 miles south of Mount Vernon, Indiana. Samples were taken from trees near the shore, both on land and in the water.This study dated some trees to 1855. Analysis of the tree rings, climate data, and river discharge data revealed that bald cypress are not declining in southwestern Indiana. The rate of tree ring growth increases as PDSI does and the rate of river discharge does not seem to affect growth much at all. Even though this is the northernmost bald cypress chronology in the midwest and therefore should be stressed according to the theory of ecological amplitude, this chronology does not fall in the category with the highest series intercorrelation or mean sensitivity. The construction of the dam in 1975 has overwhelmed the climate signal in these trees and the trees continue to be suppressed due to the current water level.