Chemical components of the branches of six hardwood species
The biomass generated from tree pruning or derived from the forest exploitations could be susceptible to chemical use and studies on chemical composition in tree branches are scarce. Therefore, in this investigation the biomass of the branches of six hardwood species (Alnus acuminata, A. jorullensis, Quercus candicans, Q. laurina, Q. rugosa and Symplocos citrea), derived from the forest use by the indigenous community of Nuevo San Juan Parangaricutiro from Michoacan State, Mexico, were used. The chemical composition in wood and bark was determined and the tannin content was evaluated by two methods of extraction: aqueous extraction and ethanolic extraction. In general, the results obtained varied as follows: pH (4.25-5.19), ash (0.08-10.23%), total extractives (6.9-49.5%), solubility to soda (25.36-70.9%), Runkel lignin (17.64-47.33 %), holocellulose (32.74-86.51%), alpha-cellulose (30.58-61.20%), tannins (0.26-10.67% by aqueous extraction, 0.23-12.21% by ethanolic extraction). No heavy metals were detected in the ash. The bark of Quercus candicans and Q. laurina, could be used for the extraction of tannins.