DETERMINANTS OF STEMWOOD PRODUCTION IN PINUS-CONTORTA VAR LATIFOLIA FORESTS - THE INFLUENCE OF SITE QUALITY AND STAND STRUCTURE

Leaf area index of mature stands of lodgepole pine was independent of stand density. Thus, stand density did not affect total leaf area, but strongly influenced leaf area per tree. Leaf area index and site index were significantly but weakly related in the lodgepole pine stands. While the growth of stem volume as significantly (r2=0.45) related to leaf area index, residual variation was associated with differences in stand structure. Mean tree growth increased with mean leaf area, but at a decreasing rate; this indicates the relatively low efficiency with which leaf area on large trees produces stemwood volume. Reduced leaf area efficiency of large trees in density stands was related to increased respiration requirements resulting from greater amounts of non-photosynthetic to photosynthetic tissue. This explanation for differences in leaf area efficiency is supported by the observation that the ratio of foliage to total crown biomass was inversely proportional to mean crown size. -Authors