Abstract

CORREIA, Alexandra et al. Simultaneous Fitting of Biomass Equations for Pinus pinea L. in Portugal. Silva Lus. [online]. 2008, vol.16, n.2, pp.197-205. ISSN 0870-6352.

We present a system of alometric biomass equations for aboveground compartments for Pinus pinea L. that allows biomass estimation with information from conventional forest inventories. We harvested 40 trees located in south of Portugal and separated and weighed all the aboveground components: needles, stem bark, branches and stem. The equations were simultaneously fitted using seemingly unrelated regression. This method allows the compatibility of the partial allometric equations with the equation for total biomass aboveground that corresponds to the sum of those 4 equations. The models were better for stem (R²adj.=0.85) and bark (R²adj.=0.83) and worst for branches (R²adj.=0.79) and needles (R²adj.=0.71). Crown biomass was always high compared with aboveground biomass, independently on stand characteristics.  However it may be exacerbated by artificial pruning that is carried out to increase crown expansion for pine nut production. The different stand management circumstances from where trees harvested were selected may explain the worst fitting for crown components.

Keywords : Pinus pinea L.; biomass; alometric models.

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