Sapwood area as an estimator of foliage biomass and projected leaf area for Abiesbalsamea and Picearubens

Abstract

Sapwood conducting area was found to be highly correlated with foliage biomass and projected leaf area in both balsam fir (Abiesbalsamea (L.) Mill) and red spruce (Picearubens Sarg.). Linear regression equations from sapwood measured at breast height (1.3 m) were as follows: for balsam fir, foliage mass = 0.138X − 1.491 (R = 0.978) and projected leaf area = 0.673X − 5.453 (R = 0.952), where X is sapwood conducting area in cm2. For red spruce, foliage mass = 0.072X − 0.410 (R = 0.914) and projected leaf area = 0.167X + 6.772 (R = 0.934). Regressions improved when sapwood area was measured at the base of the live crown. The relationship between sapwood area and foliage mass or projected area in balsam fir was very similar for trees from three sites of greatly different character, suggesting a close, species dependent, physiological relationship between crown size and the cross-sectional area of conductive xylem needed to supply water to the foliage. Thus, it appears that foliage area can be predicted from increment cores with a high degree of certainty and without concern for differences in stand condition or individual tree vigor.