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Regression models to estimate aboveground phytomass of the Floresta Baixa de Restinga

The purpose of this study was to develop equations to estimate the aboveground phytomass of the Floresta Baixa de Restinga. We selected 102 trees of 29 species occurring in the study area and 102 trees of Syagrus romanzoffiana (Cham.) Glassman, distributed proportionately among the diameter classes of trees. The trees were cut at ground level and the total height and diameter at breast height (DBH) of each tree were measured. Leaves and woody material were separated in order to determine their fresh weights under field conditions. Samples of each fraction were oven dried at 70 °C to constant weight to determine their dry weight. The models were developed by using single linear regression analysis, where the dependent variable was the dry mass (DW), and the independent variables were height (h), diameter (d), the product of diameter and height (d² h) and the product of diameter, height and woody density (ρ d² h). The models developed indicate that the diameter explains much of the variability of the trees phytomass and the tree height is the explanatory variable of the specific equation for Syagrus romanzoffiana. The best equations to estimate aboveground phytomass were: ln DW = -1.352 + 2.009 ln d (R² = 0.96; s yx = 0.34) for the community without Syagrus, ln DW = -2.052 + 0.801 ln d² h (R² = 0.94; s yx = 0.38) for the community with Syagrus and ln MS (kg) = -0.884 + 2.40 ln h (R² = 0.92; s yx = 0.49) for Syagrus.

Atlantic Forest; allometry; biomass; forest biomass estimation; Syagrus romanzoffiana


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