Preliminary evaluation of environmental variables affecting diameter growth of individual hardwoods in the Southern Appalachian MountainsThis article is part of a larger document. View the larger document here.
The value of environmental variables as measures of site quality for individual tree growth models was determined for 12 common species of eastern hardwoods in the Southern Appalachian Mountains. Periodic diameter increment was modeled as a function of size, competition and environmental variables for 1,381 trees in even-aged stands of mixed-species. Resulting species models explained from 46 to 78 percent of total variation in diameter increment, of which environment accounted for 3 to 17 percent of the total explained. In similar model formulations where site index replaced environmental variables, it accounted for only 0.01 to 3.6 percent of variation. An important finding was the significant relationship of growing season length and precipitation with diameter increment. Results of testing a selected model with an independent data set indicate that environmental variables are useful as measures of site quality.