Resumo:
Biomass exportation from Pinus taeda L. plantations thinned at different ages Three Pinus taeda l plantations with 7,10 and l 4 years old, ready to be submited to the first, second and third tltinnings respectively, were sampled in order to deternine the dry matter from above = stump parts of removed and remaining trees. Fifty one, thirty nine and twenty five sample trees of 7, 10 and 14 years old plantations respectively, were selected and sampled to cover the full range of the trees diameters (DBH). Regression equations for estimating the weights of the trees components based on DBH were developed. Before thinning, the 7 years old plantation, with 2,062 trees/ha, contained 72. 7 t/ha of biomass, including 13% of needles, 23% of branches, 7% of bark and 5 7% of wood, the I0 years old plantation, with 1,240 trees/ha, contained 145,9 t/ha of biomass, including 7% of nedles, 16% of branches, 7% of bark and 70% of wood and the 14 years old plantation, with 731 trees/ha, contained 183.8 t/ha of biomass, including 5% of needles, 15% of branches, 6% of bark and 74% of wood. The thining of 38.4, 40.7 and 39.3% of trees removed 11, 36 and 49 t/ha stem wood plus bark from 7, 10 and 14 years old plantation respectively. The branches and needles, as slash of thinning operations, weighed approximately 7, 10 and 12 t/ha respectively.
