Information on site quality, the capacity of forested land to grow wood, is an important component in forest inventories. Site index and site class are two variables that describe forest site quality. Site index is usually defined as the average total height that the dominant and codominant trees in fully stocked, even-aged stands will attain at key ages. Site class is a classification of forest land in terms of the capacity to grow repeated crops of industrial wood. This classification is based on the maximum mean annual increment, in cubic feet per acre, of natural, well-stocked, even-aged stands of species suitable to the local site. This paper documents and describes the equations, methods, and data used by the Forest Inventory and Analysis program of the U.S. Department of Agriculture Forest Service, Southern Research Station, to estimate site index and site class for forest inventories conducted in the Southern United States.
Vissage, John S.; Greer, Travis R., Jr.; Brandeis, Thomas J. 2019. Site class and site index: two estimates of site quality for the Southern Research Station Forest Inventory and Analysis Program. e-Res. Note SRS-025. Asheville, NC: U.S. Department of Agriculture Forest Service, Southern Research Station. 13 p.