Searching for Flood Rings in Quercus Macrocarpa on the Lower Chippewa River

Abstract

Dendrohydrology studies offer annually resolved flood data for paleofloods, those occurring before modern instrumentation, especially for high magnitude, low-frequency events. These events can lengthen the current flood record and can improve estimates of flood recurrence intervals. In temperate regions such as the Chippewa River valley, there is a lack of paleoflood investigations despite the need for investigations regarding rivers with a low gradient and slow-moving waters that lack other geomorphic evidence for paleofloods including erosion scars, old wash lines, and scouring marks. In a normal growth year, Quercus macrocarpa develop one or two rows of large earlywood vessels and small latewood vessels. Flood rings are a result of disrupted growth and are apparent in reduced mean earlywood vessel area, offset earlywood, small earlywood vessels, and overall narrower rings. Tree core samples were collected from Brush Island on the Chippewa River in Wisconsin to identify anomalous tree rings and to compare the tree-ring record to stream gauge and climate data. This study also attempts to prove that methods used in previous studies are applicable to the Chippewa River valley.