In this study the influence of fungus (Coriolus versicolor) on durability of sap and heartwood of beech (Fagus orientalis) in natural state and treated has been evaluated. Celcure and Basilit, water soluble salts were used for impregnation, with two different concentrations in solution, 1 and 3 per cent. In conducting this evaluation, kolleschale’s method according to DIN and B.S. standards (52176 and 838:1961 specification respectively) were adopted. Random block in experimental design was used.
Since beech is the most dominated commercial species in our hardwood forests, it was selected for this study. Also the selected fungus is quite harmful to majority of hardwood, particularly beech.
Specimens were treated under pressure and vacuum (Bethel procedure). There were six groups of specimens. Specimens were contaminated with cultured fungus. Contaminated samples have been conditioned (22oC, 75% relative humidity) for fourteen weeks. After this period, weight reduction, compressive strength (parallel to grain), hardness of specimens were measured. The results were as following:
Under test condition, weight reduction of samples was not significant, both in sapwood and heartwood, weight reduction showed direct relation with type of salt used and its percentage. According to standard scale untreated wood of beech is undurabl, but treatment has made it a very durable, based on the same criteria.
Compressive strength parallel to grain showed no significant difference with in specimens of both sapwood and heartwood. Reduction in compressive strength of untreated samples was highest after contamination. But in treated samples this property has increased proportionally with rate of salts percentages in treating solution. salts’ solution has improved compressive strength, except one per cent solution of Celcure. This was observed with preventing weight loss and decay.
Treatment had considerable influence on hardness and by classification of mean values of hardness, untreated samples had lowest hardness and treated specimens with, 1, 3% Celcure, 1, 2% Basilit, offered higher hardness, respectively.