Caracterização da madeira e do carvão vegetal de clones de Eucalyptus cultivados em diferentes espaçamentos no Sertão pernambucano

Abstract

The goal of this study was to characterize the wood and charcoal of Eucalyptus clones grown in different planting spacing in the semi-arid region of Pernambuco State, Northeastern Brazil, for energy purposes. To perform the study, three clones of Eucalyptus spp. were submitted to different spacing planting and collected when they were eight years old from an experimental planting located in the Experimental Station of the Agronomic Institute of Pernambuco located in Chapada do Araripe, municipality of Araripina, Pernambuco State. Six trees from each clone (C41, C11, and C39) were sampled from three different spacing (2m x 1m, 3m x 2m, and 4m x 2m). From each tree, disks were collected along the trunk in the following sections: 0% (basis), 1.30 m DBH, 25%, 50%, 75%, and 100% of the commercial height (minimum diameter of 5 cm). Once the wood samples were done, the wood and charcoal traits were evaluated. The wood properties evaluated were: the fiber dimensions, specific gravity, bulk density, moisture content, volatile matter, ash content, fixed carbon, calorific value, and energy density. For the product, charcoal, was evaluated: gravimetric yield, specific gravity, bulk density, moisture content, volatile matter, ash content, fixed carbon, calorific value, and energy density. A completely randomized design was used, considering nine treatments and six repetitions, totaling 54 sample units. The means of each treatment were compared by the Scott-Knott test, and the multivariate analysis of main components was also used. As a result, for wood traits analyzed, only the volatile matter and fixed carbon were not influenced by the spacing treatments. For charcoal analyses, it was also not observed the influence of the treatments on the gravimetric yield and ash content. Based on all variables analyzed, the E. urophylla (C41 and C39) and E. brassiana (C11) clones planted at 2 mx 1 m spacing were considered the poor properties for energy purposes, and the E. brassiana clone C11 at intermediate spacing (3m x 2m) and the E. urophylla clone C39 installed in the 3m x 2m and 4m x 2m spacings were considered the ones with the highest quality genetic materials for energy purposes.