Photographer: Gary P. FlemingAs much as 80% of the forest floor can be covered by boulders in the Rich Boulderfield Forest, which is found on slopes above the Potomac River. The slopes, which can be steep, face north to northeast. This provides protection from the direct rays of the sun and keeps things from drying out too badly on hot summer days. Ecobit: How Topography Creates Microclimates

Soil is sparse, typically occurring in spaces between boulders, but the rocks that it has weathered from are high in calcium and magnesium, making it fertile. In places where more soil has accumulated, you’ll find more wildflowers, such as squirrel-corn.

For a study in contrasts, compare this natural community with either the Sweet Birch - Chestnut Oak Talus Woodland or the Acidic Boulderfield at Harpers Ferry National Historical Park.