Estoque de energia da madeira em áreas sob manejo florestal no Rio Grande do Norte

Abstract

The objective of this work was to determine the energy density in three different areas under sustainable forest management in Rio Grande do Norte (RN). From the access to the forest inventory of each area, the selection of the species with 70% of representativity based on the importance value index (IVI) was carried out, as well as the knowledge about the real volume of wood. From each species, three trees with characteristics that represented each stand were harvested, and samples were taken for the analyzes of basic density, upper calorific value, ash content of the wood and the value of fuel value was estimated. Considering the values of the analyzes performed and the volume of wood, the quantity of energy stored by species and area was determined. The experiment was evaluated according to a completely randomized design, with 5 treatments (species) in area I, 6 in area II and 12 in area III, with three replicates in each area. The wood of the species Croton sonderianus presented a higher value of calorific value for the three areas and the Mimosa tenuiflora had a higher value of basic density and heat power in areas I and II. The same occurred for Caesalpinia leiostachya, Caesalpinia pyramidalis, Piptadenia moniliformis, Pilosocereus pachycladus and unidentified in area III, which resulted in a higher energy density in this area when compared to the others. In this way, the commercialization of the wood for energy purposes must be based on the energy density that a certain area under forest management has and not only on the volume of wood.