Middle Holocene vegetation change at Lake Tahoe (Nevada, California)

A sediment core from Lake Tahoe, California-Nevada was analyzed for pollen to determine the nature and timing of vegetation change during the middle Holocene. Turbidite layers were found to be common in the sediments, which proved troublesome. The turbidite layers and slow deposition rate at the lake left little sediment for pollen analysis. Zone 1, between 8750 and 7280 cal yr B.P., was cool and dry with high percentages of TCT (8.7%) and Artemisia pollen (4.9%) and relatively low percentages of pine pollen (69%) from 8090 to 7280 cal yr B.P. Zone 2, between 7060 and 4550 cal yr B.P., was relatively warmer and dry with TCT as Juniperus and Artemisia decreasing to 7.4% and 3.1% respectively while pine increased to almost 90% from 7060 to 5510 cal yr B.P. Zone 2 concluded with wetter trend marked by an increase in TCT as Calocedrus, Abies, Typha and Isoetes.