Propriedades da madeira de Eucalyptus urophylla x Eucalyptus grandis e projeção de biomassa e energia em plantios de curta rotação localizados no município de Macaíba-RN

Abstract

Within the context of the need for woody biomass, for energetic purposes, quality evaluations of wood provide important information about the propellant potential of this starting material, besides allowing for a choice of the appropriate genetic material to be deployed, thereby seeking high production and energetic efficiency. In the State of Rio Grande do Norte (RN), wood is widely used as a major source of energy in different activities of the industrial, commercial and residential sectors. The demand for this resource is mainly met by the extraction of species of Caatinga, which is conducted without a proper knowledge about its dynamics for appropriate handling, characterization of the material or study of the influence of the factors age and genetic material on the technological properties of the wood. This study was divided into two chapters, which were structured in scientific paper format. The Chapter I had the objectives of verifying the effect of age and genetic material on the properties of the wood of clones of Eucalyptus urophylla S.T. Blake x Eucalyptus grandis (Hill) Maiden and indicating, based on the results, the material with the best potential for energetic purposes deployed in the area of forestry experimentation of the Academic Unit Specialized in Agricultural Sciences (UAECIA) of the Federal University of Rio Grande do Norte (UFRN), Macaíba-RN. The analyses were held in the Laboratory of Panels and Energy of Wood (LAPEM) of the Federal University of Viçosa (UFV), where the wood of three genetic materials (GG100; AEC0144 and AEC0224) was evaluated for determining the basic density (Kg.m-³), superior calorific power (Kcal.Kg-1), Klason lignin, extractive content (%) holocellulose (%), as well as components of the immediate chemical analysis of wood, volatile material contents (%), fixed carbon (%) and ashes (%). The Chapter II had the objective of planning the production of biomass, lignin and energy, for the referenced clones, until ages higher than the observed in this study (three years), with the aid of models of growth and production of the total population type. The growth and production estimates for planting were held until the age of six, with the aid of the exponential model (non-linear), with a view to studying the behavior of the variables of interest: volume (m³.ha-1), dry mass (t.ha-1), lignin mass (t.ha-1) and energy (MW.h.ha-1). The regression adjustments for each clone were performed with the aid of the Statistica 7.0 software. From the analyses, it was observed that age has influenced the properties evaluated on wood, often regardless of the deployed genetic material; and the clone that stood out for energetic use was the GG100, since it has presented wood with high values of basic density, high content of total lignin and low content of ashes in all evaluated ages. Moreover, it was observed that the model for growth and production estimate has presented a good adjustment for the different variables in the level of detail total population. Lignin and dry mass estimates were particularly the parameters that have presented the best estimates in all clones, according to the values obtained for the correlation coefficient (R), which was high, and the low values for the standard error (S). It has not been verified a stagnation of the production of volume, dry mass, lignin and energy, except in the production of the AEC0224 clone, which presented ideal age of cutting around 5,92 years.