Site classification of afforested arable land based on soil properties for forest production

We used discriminant analysis to identify the key soil properties that discriminate among 30 forest sites representing a floristic site-type fertility gradient. Thereafter we classified 24 sites on afforested arable land into forest site types using these discriminant functions. The most important soil properties of the E horizon separating different forest site types were pH and the densities of Ca, P, and silt. Using properties of soil from the 0-10 cm depth to represent the current level of site productivity, we classified all soils from afforested arable land into forest site types of high productivity. Among these soils, the most fertile were those with high clay and silt densities. Again, using properties of soil from the 30-40 cm depth to emulate the site productivity that prevailed before soil-formation processes and agricultural land use altered the upper soil horizon, we classified most of the soils from afforested arable land into forest site types of medium productivity. This implies that agricultural land use had increased the densities of basic elements at the 0-10 cm soil depth and, consequently, site productivity. The high productivity of former arable lands was attributed to their previous agricultural use and to the inherent properties of fine-grained soils.