THE APPLICABILITY OF THE PIPE MODEL-THEORY FOR THE PREDICTION OF FOLIAGE BIOMASS IN TREES FROM NATURAL, UNTREATED BLACK SPRUCE STANDS

Trees were sampled from 26 black spruce (Picea mariana (Mill.) B.S.P.) stands across New Brunswick and within the boreal forest of Quebec to test the validity of the pipe model theory for sampling purposes. Trees were sampled from a wide range of ages, site qualities, densities, and social classes for determination of foliage biomass and sapwood cross-sectional areas at breast height and at the base of the live crown. A strong relationship was found between sapwood cross-sectional area and foliage biomass across the range of conditions. The y-intercepts for these regression equations, based on the untransformed data, were not significantly different from zero (P < 0.05). Partial correlation analysis indicated no significant relationship between the foliage biomass and tree age, site quality, or stand density but confirmed the strong relationship with sapwood cross-sectional area. Suppressed and intermediate social classes followed a similar relationship as dominant trees. Regression equations developed from this study were similar to those determined for spruce species and supported the use of sapwood cross-sectional area as a predictor of foliage biomass for black spruce.