Growth and Site Index of White Pine in Relation to Soils and Topography in the Glaciated Areas of Ohio

Abstract

Abstract Multiple regression equations were developed using topographic and soil factors for predicting growth and site index of white pine growing on old-field sites in the Wisconsin-aged glaciated areas of northern and western Ohio. Correlations between height growth of trees below the breast high (bh) annual growth increment and bh and above were not statistically significant and growth and site index estimates were made using age at bh and growth from the bh annual increment to the growing tip. The best estimates of heights and site index were obtained when data were subdivided into two groups. For plots having 0–10% slopes, two regression equations were developed for predicting height growth: one containing slope shape and depth to soil mottling and the other adding percent clay in the B2 soil horizon to the equation. Those equations accounted for 67 and 73%, respectively, of the variation in heights of trees and 35-year site index ranged from 62 to 82 ft, with the best growth on convex-shaped slopes having the greatest depth to mottling and the lowest clay content. For sites having slopes greater than 10%, one equation was developed containing slope position and slope percent as variables. That equation accounted for 72% of the variation in heights of trees, and site index ranged from 71 to 81 ft, with the best growth on plots at the bottom of slopes having the lowest slope percent.