Redução do efeito das tensões de crescimento em toras de Eucalyptus dunnii

Abstract

O objetivo deste trabalho foi testar cinco técnicas de obtenção de toras de Eucalyptus dunnii para redução dos efeitos das tensões de crescimento. Após a obtenção e desdobro das toras, foram avaliados as rachaduras, arqueamento, encurvamento e encanoamento. Toras com selante de topo apresentaram os maiores índices de rachaduras (12,05%) e encurvamento nas tábuas; toras aneladas, menor arqueamento (0,38 mm/m) e toras com herbicida, menor encurvamento (3 mm/m). O anelamento e aplicação de herbicida foram mais eficientes na redução do efeito das tensões de crescimento.

The objective of this study was to test five different methods to minimize the effects of growth stress on the production of Eucalyptus dunnii sawlogs. The boards produced were then evaluated and measured for splits, springs, bows and cuppings. The treatment where the end coating was applied to the sawlogs showed the highest splits and bows (12,05 %); the treatment where cuts 1/3 of the radius were applied to the trees showed the lowest spring rate (0,38 mm/m); the experiments where trees were treated with the herbicide Chopper [Imazapyr (Basf)] showed the lowest bow rate (3mm/m). Both experiments where trees were treated with the herbicide Chopper and where the sawlogs were treated on their ends through cuts 1/3 of the radius were the most efficient to the reduction of the growth stress effects.