Investigation of the Natural Durability of Beech Wood by Meyer-Veltrup Model

Recognition of the natural durability of wood and industrial species of each country is essential and Iran is no exception to this rule because of valuable commercial species. Generally, the natural durability of wood is determined in the laboratory and field by measuring the decay resistance of wood according to EN 113 and EN 252. However, Meyer- Veltrup et al. proposed a new method entitled "resistance model" to estimate the natural durability with more accuracy which can be generalized to conditions without soil contact. In this model, two factors namely inherent resistance and wetting ability are used. Beech (Fagus orientalis) was selected as one of the most important commercial species in Hyrcanian forests to study its natural durability. The results showed F. orientalis heartwood and sapwood were less durable and non-durable (DC 4–5). Water immersion after 1 and 24 hours was highest for sapwood followed by heartwood. Based on the MLF index, 61 % of sapwood was attributed to the white fungus (T. versicolor) as well and the lowest MLF was caused by sapwood and heartwood by the H. Fragiforme. 43.5 % of MLF on beech wood is caused by terrestrial organisms (TMC). Based on the resistance model, the first signs of decay were observed after 312 and 294 days.