VEGETATION AND FLORA OF AMERICAN BEECH WOODS NATURE PRESERVE, CLARK COUNTY, ILLINOIS

摘要

American Beech Woods Nature Preserve is located on Illinoian till in the Wabash Border Division of eastern Illinois. The plant life of this 8 ha site was examined during the 1999-2001 growing seasons. We documented a total of 207 vascular plant species in 148 genera of 71 families (10 pteridophytes, 1 gymnosperm, 49 monocots, and 147 dicots). We also sampled the vegetation using a stratified-random line-strip method. Tree density averaged 249 trees/ha with a basal area of 22.91 m~2/ha. Fagus grandifolia Ehrh. (American beech) was the dominant tree species with 63 trees/ha, a basal area of 7.34 m~2/ha, and an importance value 26.1 (possible 100). Acer saccharum Marsh, (sugar maple) ranked second in importance value (IV = 15.7) with most individuals in the 10-19.9 cm diameter class. Quercus velutina Lam. (black oak) and Carya glabra (Mill.) Sweet (pignut hickory) were the only other over-story trees with an importance value greater than 10. In comparison with an earlier study in 1973, the site has experienced a decrease in both tree density (399 trees/ha vs. 249 trees/ha) and basal area (33.35 mVha vs. 22.91 mVha).