savanna with oak and hickory trees, maintained by fire, in the Piedmont physiographic province
Source: Virginia Native Plant Society (VNSP), Home is Where the Grassland Is with Chris Ludwig
The presence of so many grassland plant species in Virginia demonstrates that prairie-like habitat was common before settlement in the 1600's began to transform the landscape. Perhaps the most significant human impact after conversion of so much acreage to farmland was the reduction in wildfires.
With 40-50 inches or rain per year, natural plant succession on an old field will produce a forest within several decades. Grasslands existed because fires burned acreage every 5-10 years. In addition to natural fires caused by lightning, Native Americans intentionally burned the woods.1
Source: Virginia Native Plant Society, Virginia Native Grassland Restoration
Source: West Virginia Department of Commerce, The Savanna - West Virginia Forestry