A comprehensive evaluation of spruce-fir growth and yield in Maine as related to physical and chemical soil properties.

摘要

The purpose of this dissertation was to use an archived data set from nine M.S. theses to conduct a comprehensive evaluation of site quality of naturally occurring spruce-fir stands in Maine.;Potential height growth patterns of spruce and fir were quantified by using the two fastest growing trees of spruce and fir from each sample plot. The distribution of growth curve patterns among sampled plots showed that: (1) 35% were linear; (2) 35% were sigmoid; (3) 20% were convex, and (4) 10% were concave. Site indices ranged from 35- to 70-feet (height at 50-years breast height age), with 50% of the trees having site indices between 45 and 55 feet. Linear and nonlinear site index and height development curves were formulated, and resulted in families of curves that were different than those developed by Vicary (1982).;Quantifications of site variability showed that the distributions of soil drainage and critical depths of rooting and restrictive layers were unbalanced among western, northern, and eastern study regions, with more poorly drained soils and shallower critical depths in the northern region. Textural differences were also evident among regions, with eastern soils higher in sand, northern soils higher in clay, and western soils higher in silt than other regions. Means and ranges of 26 physical and 30 chemical soil variables indicated that most were highly variable among sample plots. Principal components analyses showed that variations in soil chemistry were greater than variations in physical properties.;Stepwise regression was used to quantify relationships between soil and site index and mean annual increment in volume. Results indicated that a small subset of non-correlated soil variables could be used to estimate growth responses of spruce-fir stands with levels of precision (R