Historic vegetation of the Nature Conservancy's Chinquapin Preserve, Woodford County, central Illinois.

The historic vegetation of The Nature Conservancy’s (TNC) Chinquapin Preserve located in Woodford County, Illinois, and some of the surrounding area, which included three townships (Kansas, Palestine, and Montgomery), was determined using the General Land Survey Field Notes (1821-1833). Vegetation densities at section and quarter section points were estimated using a modified point-centered quarter method and placed in four density-based categories (prairie, savanna, open forest, and closed forest). The historic vegetation was primarily prairie (55.5%) and savanna (35.3%) with oak and hickory dominated forests occurring along waterways and ravines. White oak, black oak, and hickory accounted for 81% of all trees in the study area. The field notes for the three townships were notable for the absence of maple tree records, which are an important taxon in current upland forest of the study area. The Conservancy’s property, as described by surveyors and based on our analysis, ranged from treeless prairie to closed forest. The forests in the area of the properties were all described as, “oak hickory” forests. This study indicates that restoration of The Nature Conservancy’s properties to correspond to historic vegetation should include forests dominated by white oak, black oak, and hickory trees (with a few elm and walnut trees) near the river channel, and savanna grading into prairie away from the Mackinaw River. Sugar maple (Acer saccharum) should be nearly eliminated from forests on upland sites.