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Effect of thinning in the end splits of the logs of Eucalyptus grandis W. Hill ex Maiden/Efeito do desbaste nas rachaduras de topo das toras de Eucalyptus granais W. Hill ex Maiden
Ist Teil von
Ciência florestal, 2014-01, Vol.24 (1), p.193
Ort / Verlag
Universidade Federal de Santa Maria
Erscheinungsjahr
2014
Link zum Volltext
Quelle
EZB Free E-Journals
Beschreibungen/Notizen
The study was undertaken to evaluate the effect of thinning in the end splits of the logs of the Eucalyptus granais at 18 years of age. There was analyzed a thinning experiment, located in the northern coast of Rio Grande do Sul State, Brazil, installed in randomized blocks with four repetitions. The seven treatments were defined according to the number of thinnings applied and ranged from zero to six interventions. The trees were selected, in each treatment, on the basis of the Assmann's dominant diameter and the central diameter of tree, being referred to as dominant and central trees, respectively. After cutting down the selected the logs were located between the DBH (diameter at breast height) and 25% positions, 25% and 50%; 50% and 75%; 75% and 100% of the commercial height, for the end split study. The results indicate that the average end splits of the logs in the dominant and central trees was higher at the second log sampled, suggesting that sectioning should be carried in conjunction with techniques that minimize the growth stress, especially when this is performed near the half of the commercial height. The thinning induced variation in the logs end split, both for dominant and central trees; however, there was no clear positive or negative trend, leading to the conclusion that changes in growth rate did not affect these parameters uniformly. Keywords: Eucalyptus; silvicultural treatments; wood quality. O estudo teve como objetivo avaliar o efeito do desbaste nas rachaduras de topo das toras de Eucalyptus granais aos 18 anos de idade. Para tanto, foi analisado um experimento situado proximo ao litoral do Rio Grande do Sul, instalado em delineamento blocos ao acaso com quatro repeticoes. Os sete tratamentos foram definidos devido ao numero de desbastes aplicados e variaram de zero ate seis intervencoes. As arvores foram selecionadas, em cada tratamento, com base no diametro dominante de Assmann e no diametro da arvore central, sendo denominadas de arvores dominantes e centrais, respectivamente. Apos o abate foram selecionadas as toras localizadas entre as posicoes do DAP (diametro a altura do peito) e 25%; 25% e 50%; 50% e 75%; 75% e 100% da altura comercial para o estudo das rachaduras de topo. Os resultados indicaram que o indice medio de rachadura de topo das arvores dominantes e centrais foi maior na segunda tora amostrada, evidenciando que a toragem das arvores deve ser realizada em conjunto com tecnicas que minimizem as tensoes de crescimento, principalmente quando o seccionamento for realizado proximo a metade da altura comercial. O desbaste induziu a variacao do indice medio de rachadura de topo das toras, tanto nas arvores dominantes quanto nas centrais; porem, nao foi verificada uma tendencia clara positiva ou negativa, podendo-se concluir que alteracoes na taxa de crescimento nao afetaram esse parametro de maneira uniforme. Palavras-chave: eucalipto; tratos silviculturais; qualidade da madeira.