basal area

The area of the cross section of a tree at height of 4.5 feet above the ground, generally written as the total of the basal area of the trees in a forest in square feet per acre. The surface of the soil actually covered by a plant, as compared to the full spread of the herbage, in grassland ecology often measured at one inch above the ground. (alt. basal cover, alt. ground cover, alt. cover)