A potential quantitative method for assessing individual tree performance

By what standard should a tree be judged? This question, perhaps unknowingly, is posed almost daily by practicing foresters. Unfortunately, there are few cases in which clearly defined quantitative (i.e., directly measurable) references have been established in forestry. A lack of common references may be an unnecessary source of error in silvicultural application and potentially confounds efforts to understand the biology and ecology of forest processes. The utility of the few references that have been established is immense. For example, foresters can assess site productivity for an area by calculating site index, which is a standardized, quantitative reference for site productivity. Moreover, foresters can compare site productivity across multiple areas (say, the Missouri Ozarks versus southern Indiana) because site index is a common reference that is widely accepted. Similarly, foresters can evaluate and compare stand density by calculating stocking percent.