Morphological and Mechanical Aspects of the Micro Defects in Relation to Deterioration of Wood

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The purpose of this study is to clarify the morphological features of the slip planes and the incipient decay portion within the cell walls, and to evaluate the influence of their micro defects on mechanical properties of solid wood.The slip planes within cell walls were closely related to mechanical deterioration of wood. The presence of slip planes drastically decreased strength and toughness of solid wood. At the low precompression level, the slip planes distributed randomly and thinly. The slip planes tend to concentrate at the compression failure zones, as the precompression stress level increased. Final breakage of the precompression wood occurred at the compression failure zone, and the cracks always propagated through the slip-plane site.The cells walls were seriously decayed by the wood-rot fungi and bacteria. The chitosan-coated wood showed high resistance to decay by the fungi, and remarkable anti-fungal effect was recognized for COV and SEL. The chitosan-coated cell-wall showed no evidence of enzymatic degradation and adherence of fungus on the surface of the cell wall.