Prediction of Oak Site Index in the Ridge and Valley Region of Pennsylvania

A site index prediction equation for oak stands was developed from data of 39 permanent sample plots in southcentral Pennsylvania. The utility of the equation, SI 50 = B 0 + B 1 (slope position) + B 2 (slope) + B 3 (depth of A 1 + A 2 + B 4 (silt) + B 5 (Ca) + B 6 (Mg) + B 7 (N), further tested on 16 additional plots, compared favorably with a standard method of site index determination. The prediction equation accounted for 79 percent of the variation in site index. Calcium, magnesium, and nitrogen concentrations in the A 1 + A 2 soil horizon were very important to the prediction of site quality on these soils. Forest Sci. 18:192-195.