INFLUÊNCIA DO ESPAÇAMENTO NAS PROPRIEDADES ENERGÉTICAS E BIOMASSA DE Eucalyptus benthamii Maiden et Cambage

Abstract

The burning of fossil fuels has generated environmental problems of great impact, among them the global warming stands out. The usage of renewable sources of energy, such as the biomass, must be widely spread with the objective of minimizing these impacts. The energetic potential of biomass, mainly in the form of firewood, is evaluated for its physical, chemical and energetic properties. The aim of this study was to evaluate the influence of different spacings in the energetic properties and in the production of biomass of Eucalyptus benthamii, at the age of 6. The experiment was carried out in Guarapuava municipality, Paraná, in a randomized block design (DBA), with 4 treatments, which correspond to the planting spacing: 3 x 2m, 3 x 3m, 4 x 3m and 4 x 4m, being the treatment composed of 4 repetitions with 20 trees each. Five more frequent diametric classes were obtained through Sturges equation totaling 60 trees. These trees were cut and their compartments – wood, bark, branches and leaves were weighed separately. Samples for each compartment were utilized to estimate the dry biomass, energetic analysis of calorific value, immediate chemical analysis and basic density of the wood. An economic analysis was also carried out to verify the viability of substituting BPF oil by biomass such as wood chips and firewood in logs. The total dry biomass estimated by hectare was higher for spacing 3 x 2m with 184.16 Mg ha-1. For the basic density, the average found was 0.500 g cm-3 and no difference among spacings was found. Nevertheless, there was significant difference in the different heights along the stem. For the gross calorific value, the highest average found was for branches and leaves with 4.731 kcal kg-1 and there was no significant difference between the spacings. For the immediate chemical analysis, there was no significant difference among the spacings, but the assessed compartments showed differences for the contents of volatile materials, fixed carbon and ashes. The usage of biomass as firewood, substituting the BPF oil and wood chips biomass, was economically viable.