Identification of low productivity sites for European larch (Larix decidua Miller) in Maine, USA

Abstract

As silvicultural capital becomes limited, allocation of funds to high quality sites becomes critical and sites with low productivity potential should be avoided. Data collected from 31 plots located in 12 plantations established between 1930 and 1982 throughout central Maine were used to develop a soil-based rule to identify sites having a low productivity potential for European larch in Maine, thereby removing them from consideration for plantation establishment. Stepwise regression and discriminant analyses identified several variables that were associated with site index at an index age of 20 years breast height (SI20): solum thickness, B horizon clay content, and B horizon exchangeable K. Using these variables, a classification rule was developed to classify sites into 2 categories (poor, average SI20=14.7 m; and good, average SI20=17.7 m). Cross-validation demonstrated that the classification functions correctly identified 88% of the poor sites and 81% of the good sites.