Vegetation of Certain Sand Plains of Connecticut

Abstract

Historical, soil profile, and vegetational studies showed that the plant communities lying above the influence of the ground water table on coarse sandy terraces in the townships of Wallingford and North Haven, Connecticut, are mainly stages in 3 subseres which probably lead up to a xerophytic oak "edaphic climax." The subseres are developing on ridges of wind-deposited sand, superimposed on a grassland type of soil profile; level areas with a truncated soil profile, lacking an A horizon; Level areas with soil profile intact. The differentiation of initial habitats resulted from, and followed, the cultivation and wind erosion of the areas in the 18th century. The vegetation on the ridges consists of trees, primarily Quercus velutina and Betula populijolia, forming an open canopy, with a scattering undergrowth of forbs, especially Poly-gonella articulata, grasses, shrubs, and occasional mats of mosses and lichens. Truncated soils have an extremely open cover of Andropogon scoparius and Trichostema dichoto-mum. Increase in abundance and cover is brought about primarily through unintentional burial of seeds by man. "Normal" soil profiles for the most part carry a complete cover of vegetation, primarily a community of Andropogon scoparius, Cladonia spp., and Polytrichum pilijerum, though occasionally the cover consists primarily of Hypericum gentianoides. Forests of Quercus velutina and Pinus rigida, and scrub and woodland of various species also occur, and are mainly successional stages following the Andropogon-Cladonia association. Q. velutina invades many communities through burial of its acorns by squirrels. Mechanical analysis, moisture equivalent, loss on ignition, and acidity values of the soils of various communities show differences related primarily to the presence or absence of erosion and deposition phenomena. Evaporation rates, maximum surface soil temperatures, and available soil moisture in summer, are highest in the Trichostema-Andro-pogon community and lowest in the forest communities.