A fast method for monitoring foliage density in single lower-canopy trees.

A subjective visual assessment of foliage density is the most widely used rapid method of determining forest health. For these assessments to be ecologically meaningful they must be reliable (have low inter- and intra-observer variability) and readily relate to a measure of physiological or physical stress. A simple rapid method for assessing percent foliage density in lower stature trees is described. This method has low inter-observer variability (standard deviation between observers=8.6%) and therefore, minimizes the risk of confounding the effects of different observers with genuine changes in density. The percentage changes in this measure of foliage density correlate well with percentage changes in biomass, allowing a ready interpretation of observed changes. The technique does not specifically identify the cause of the measured changes, however, with appropriate additional measures this problem may be overcome.