Holocene forest development and paleoclimates within the central Sierra Nevada, California

The pollen and plant macrofossils in sediments from three high-altitude lakes in the Sierra Nevada, California, document vegetation changes that have occurred over the last 12 500 years. Trees became established around the lakes by c. 10 000 years ago. By c. 6000 BP, effective precipitation had increased, as shown by an increase in subalpine conifers, principally Tsuga mertensiana (mountain hemlock) and Abies magnifica (red fir). The upper altitudinal limits of many subalpine conifers began to fall c. 2500 BP, coincident with the beginning of Neoglacial cooling. -from Author