Influence of xylem ray integrity and degree of polymerization on bending strength of beech wood decayed by Pleurotus ostreatus and Trametes versicolor

• Oriental beech wood, exposure to two white-rot fungi.
• An investigate the relationship between molecular, chemical and anatomical alteration with mechanical instability of wood decayed by two white-rot fungi.
• Determine the relationship between impact bending strength and changes in the DP of cellulose and chemical composition.

The scope of this research was to evaluate the influence of xylem ray (XR) and degree of polymerization (DP) of holocellulose in Oriental beech wood (Fagus orientalis Lipsky.) on impact bending strength against two white-rot fungi. Beech wood specimens, exposed to Pleurotus ostreatus and Trametes versicolor, were evaluated for impact bending strength at 15-day intervals for 120 days. Microscopic evaluations at each time interval indicated that both fungi degraded marginal ray parenchyma at early stages of decomposition causing a drastic loss in impact bending strength. However, the two fungi differed in their ability to reduce DP; DP and xylem ray integrity (without precedence) were the most important factors in mechanical stability of beech wood.