Contemporary Pollen Rain across the Central Sierra Nevada, California, U.S.A.: Relationship to Modern Vegetation Types

Publisher Website
Google Scholar
Abstract
The relationship between the modern pollen rain and vegetation of alpine areas within the central Sierra Nevada in California is examined. Cluster analysis is used to help designate six major groups, corresponding to modern vegetation units. Abundant oak percentages characterize the oak grassland/woodland and chaparral. High oak and T-C-T (members of the Taxodiaceae-Cupressaceae-Taxaceae) distinguish the modern Sierra montane forest. Abundant pollen of red and white fir, with montane chaparral shrubs, characterize the upper Sierra montane and upper montane forests, while highest mountain hemlock pollen percentages are found in the subalpine forest. Sagebrush pollen dominates sites at most elevations east of the crest. Nonarboreal vegetation types are not distinguished palynologically in this cluster analysis, perhaps due to a paucidity of samples. Pollen percentage limits for the local occurrence of a taxon are also established. Mountain hemlock and fir trees are absent at pollen percentages of less than 1% and 2 to 4%, respectively. At low elevations pine trees are absent when pollen percentages are 24% or less. The above results can be applied directly to studies of late Quaternary vegetation and climatic change of the area; most of the changes in past vegetation involved these taxa.