Growth data from the most recent 5 years of a 40-year thinning study in an even-aged red pine (Pinus resinosa) forest in cutfoot sioux experimental forest, Minnesota, were used with intercepted photosynthetically active radiation (IPAR) data to determine the relationship between light interception and growth for a range ofstand densities. Stand basal area (BA) growth was proportional to the amount of light intercepted within the stand (P = 0.06 r2 = 0.73), and individual tree growth was inversely related to the amount of light intercepted by the canopy (P = 0.08, r2 = 0.69). Stand growth efficiency (SGE = ratio of 5-year plot BA growth to plot median %IPAR) was only weakly correlated with stand density (p < 0.10, r = 0.31). The rate of change in stand growth efficiency may be a good indicator of change in forest condition over a range of stand densities.
Law, Beverly E.; Riitters, Kurt H.; Ohmann, Lewis F. 1992. Growth in relation to canopy light interception in a red pine (Pinus resinosa) thinning study. Forest Science, Vol. 38(1): 199-202