_______________ area is derived from tree diameter and defined as the cross-sectional area (usually in square feet) of a tree at DBH.

Basal area is a specific term used in forestry to represent the cross-sectional area of a tree measured at breast height, known as diameter at breast height (DBH). This measurement is crucial as it helps foresters and ecologists understand tree density and biomass within a given stand or area. The basal area is commonly expressed in square feet per acre and is an important metric for assessing the overall health and productivity of a forest. By taking the diameter of the tree and applying the formula for the area of a circle (πr^2), one can calculate the basal area, which directly influences forest management decisions, including timber yield estimation and habitat assessments. Understanding this concept is fundamental for those working in forestry, as it directly relates to resource management and conservation efforts.