Abstract

MURACE, M et al. Behavior of Pinus ponderosa Dougl. ex. Laws. exposed to the brown rot fungus Gloeophyllum sepiarium (Wulf.: Fr.) P. Karst. Quebracho (Santiago del Estero) [online]. 2014, vol.22, n.2, pp.114-124. ISSN 1851-3026.

The fungal degradation is a frequent and aggressive type of deterioration in the service wood. Therefore, the wood resistance to deterioration by xylophagous fungi is a reference property to estimate its useful life in extreme condition of use and, consequently, to define its condition more suitable of use. For a certain class of resistance to degradation, the useful time in service of a piece exposed to structural solicitation will be influenced by the type of rot. The brown rot reduces significantly the mechanical strength. Objective: to determine the behavior of Pinus ponderosa Dougl. ex. Laws. wood exposed to Gloeophyllum sepiarium (Wulf.: Fr.) P. Karst, liable for brown rot. Worked with sapwood obtenied from trees of 19 years old implanted in Neuquen (Argentina). Resistance to fungal degradation as well as chemical composition, static bending and normal density in control and exposed to degradation wood were determinated. P. ponderosa was moderately resistant to G. sepiarium (weight loss: 35%); in the exposed wood to the xylophage fungus, the parameters of static bending decreased significantly compared to control wood (MOR in a 49%; MOE in a 55%) with low value of weight loss (1,3%), but not the density (control: 0,40 g.cm-3; exposed to degradation: 0,39 g.cm-3); the degradation was evidenced chemically and indirectly through the fall of  MOR y MOE.

Keywords : Ponderosa pine; Brown rot; Physical-mechanical properties; Chemical composition of wood.

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