Corresponding Patterns of Contemporary Pollen and Vegetation in Central North America
T. Webb, III, J. H. McAndrews, 1976. "Corresponding Patterns of Contemporary Pollen and Vegetation in Central North America", Investigation of Late Quaternary Paleoceanography and Paleoclimatology, R. M. Cune, J. D. Hays
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Use of modern pollen spectra as a basis for interpreting diagrams of fossil spectra requires compilation of the modern spectra in readily accessible form, such as contoured maps of percentage values of individual pollen types. Maps are presented that show the distribution of modern pollen based on 606 samples from central North America (lat 35°N to 70°N, long 75°W to 110°W). Only data published after 1960 are included, and data from 69 sites are presented for the first time. The maps show differences in the pollen percentages among vegetational regions. For example, peak pollen values of Cyperaceae and Betula occur in the tundra; high values of Picea appear in the northern boreal forest; high values of Pinus appear in the southern boreal forest and the adjacent conifer-hardwood forest; high values of Tsuga, Fagus, and Acer occur eastward in the conifer-hardwood forest; high values of Quercus, Ambrosia, Fraxinus, and Carya occur in the deciduous forest; and high values of nontree pollen (Gramineae, Artemisia, Chenopodiineae, and Compositae) appear in the prairie.
Trend-surface analysis and principal components analysis summarize the regional trends of each pollen type and illustrate the patterns of covarying pollen types within the data. Although these data provide a basis for interpreting the major fossil pollen zones for Holocene time in central North America, additional sampling and more detailed examination of the data are required for description of the fine-scale changes within fossil zones.