Professor Davis will conduct analyses of pollen deposits to determine how the climatic effects of the Sierra Nevada of eastern California have changed from the last glacial maximum to the present. The Sierra crest currently separates dryland vegetation to the east from mesic forest vegetation to the west. In the last glacial age the boundary was not as sharp; vegetation was similar on both slopes of the Sierra. This project will examine the timing of vegetation changes and will attempt to determine what combination of precipitation and temperature changes produced the documented shift in vegetation patterns. The results of this research will increase our understanding of processes of climatic and vegetation change and the ways regional changes are related to global changes.