The use of overlays in site quality mapping

When a sizable forested area is to be managed, some kind of map site quality for that area is necessary so that a determination can be made of the amount and distribution of lands having different levels of site quality. A manual method for chloropleth mapping of red oak site quality using soil-site studies was developed. It mapped site quality as a function of slope gradient, slope position, slope orientation, and soil depth. It consisted of selecting the soil-site study, establishing a uniform mapping format, classifying the independent variables into mapped or mappable ranges, mapping each independent variable separately, and manually overlaying these maps to produce a single site-quality map. The accuracy of the result, the usefulness of the method, and the possibility of different procedures in other studies are discussed.