The synthesis presented in this volume is a direct outgrowth of our ten-year FORMAP Project (Forest Mapping Across Eastern North America from 20,000 yr B.P. to the Present). Many previous research efforts in paleoecology have used plant-fossil evidence as proxy information for primarily geologic or climatic reconstructions or as a bio stratigraphic basis for correlation of regional events. In contrast, in this book, we deal with ecological questions that require a holistic perspective that integrates the interactions of biota with their dynamically changing environments over time scales up to tens of thousands of years. In the FORMAP Project, our major research objective has been to use late-Quaternary plant-ecological data sets to evaluate long-term patterns and processes in forest de velopment. In order to accomplish this objective, we have prepared subcontinent-scale calibrations that quantitatively relate the production and dispersal of arboreal pollen to dominance in the vegetation for the major tree types of eastern North America. Quantification of pollen-vegetation relationships provides a basis for developing quan titative plant-ecological data sets that allow further ecological analysis of both individual taxa and forest communities through time. Application of these calibrations to fossil pollen records for interpreting forest history thus represents a fundamental step beyond traditional summaries based upon pollen percentages.

Inhaltsangabe1. The Nature of Long-Term Vegetational Change.- Long-term patterns and processes in forest communities.- Spatial and temporal scale.- The scale paradigm.- The mega-scale domain.- The macro-scale domain.- The micro-scale domain.- Quaternary environmental changes as forcing functions.- Episodes of continental glaciation in Earth history.- Pacemaker of the late-Cenozoic Ice Ages.- Leads and lags in response of environment and biota to climatic change.- Anthropogenic influences.- Models of stability and dynamics of forest communities.- A north-to-south transect through the last 20,000 years.- The role of changing disturbance regimes.- Conclusions.- 2. Modern Pollen-Vegetation Relationships.- Production and dispersal of pollen grains.- Pollen production and mechanisms for dispersal.- Temporal patterns of pollen dispersal.- Spatial patterns of pollen dispersal.- Calibration of the relationship of modern pollen assemblages to extant forests.- The representation of temperate and boreal tree taxa in modern pollen samples and forest vegetation.- Regional pollen-vegetation relationships in eastern North America.- Regional studies elsewhere in the northern Temperate Zone.- Subcontinent-scale pollen-vegetation calibrations in eastern North America.- Conclusions.- 3. Reconstructing Long-Term Forest Changes From Fossil-Pollen Data.- Comparison of quantitative techniques for reconstruction of past vegetation.- Taxon calibrations.- Modern analogue methods.- Forest simulation models.- A case study in comparison of taxon calibrations, modern analogue techniques, and simulation models as different approaches for quantifying past vegetation.- The late-Quaternary pollen record from Anderson Pond.- Results of taxon calibrations applied to Anderson Pond.- Results of analogue measures applied to Anderson Pond.- Results of the FORET simulation model at Anderson Pond.- Advantages and disadvantages of quantitative methods for forest reconstruction.- Generating late-Quaternary plant-ecological data sets.- Conclusions.- 4. Vegetation Map Patterns at the Biome Level.- Constructing paleogeographic maps.- Physical geography.- Site selection and chronologies.- Paleovegetation maps for eastern North America: 20,000 yr B.P. to the present.- Characterization of modern vegetation by pollen assemblages.- Selecting time planes for mapping.- Interpretation of paleovegetation maps.- Patterns of paleoclimate inferred from maps of paleovegetation.- The relationship of modern climatic regions to vegetation.- Biotic responses to changing atmospheric circulation patterns during the late Quaternary.- Conclusions.- 5. Tree Population Dynamics During the Past 20,000 Years.- Population trajectories through time.- Documentation of changing number and density of paleoecological sites through time.- Minimum, maximum, and mean values of dominance through time.- Determination of contour intervals of dominance scaled to the population characteristics of each taxon.- Temporal changes in areal extent and dominance structure of tree populations.- Contoured paleo-dominance maps for major tree taxa in eastern North America.- Fir (Abies).- Maple (Acer).- Birch (Betula).- Hickory (Carya).- Hackberry (Celtis).- Cedars and cypress (Cupressaceae and Taxodiaceae).- Beech (Fagus grandifolia).- Ash (Fraxinus).- Walnut (Juglans).- Tamarack (Larix).- Tupelo (Nyssa).- Spruce (Picea).- Pine (Pinus).- Aspen or Cottonwood (Populus).- Oak (Quercus).- Willow (Salix).- Basswood (Tilia).- Hemlock (Tsuga).- Elm (Ulmus).- Conclusions.- 6. Late-Quaternary MIgrational Strategies of Tree Species.- Ecological areography.- Measurements of perimeter/$$\sqrt {area}$$.- Ecological areography of eastern North American tree taxa.- Migrational strategies of tree taxa.- The r-migration (rm) strategist.- The K-migration (Km) strategist.- The fugitive-migration (fm) strategist.- Stress tactics.- Late-Quaternary patterns and processes of migration.- Examples of r-migration (rm) strategists.- Examples of K-migration (Km)