study on the physical and mechanical changes of beech wood due to storage in the forest and activity of the fungus

Remaining wood in the forest after cutting decreases the wood quality by the activity of the destructive factors of the wood, especially the fungi. thus the quality of the wood produced by the low quality wood is not durable and Increasing the damage of wood products consumers and increasing the need for cutting trees and destroying the forest. The purpose of this study was to measure the amount of damage to the beech Bolts trees after three period 4 months (12 months) of storage in the forest and compare it with the beginning of the period and identify the destroyer fungi that appeared. This research was carried out in part of One in Shastkolah forestry project in Gorgan on Fagus orientalis. 15 Billets from 30 cm diameter class and length of 220 cm from a beech tree and all were healthy, inside the field under the same conditions and in contact with soil stored. The Billets were numbered and cut at 50 cm intervals at each stage and transferred to the wood working room for physical and mechanical experiments, dried at the wood working room in the open air, and then dry density, basic density water absorption, volumetric Shrinkage, End an side Hardnesses, Toughness and Static bending were measured based on conventional methods and related standards. Statistical analysis of the results was performed by means of ANOVA test and comparison of averages with Duncan's test (using Spss16 software). Observed fungi were collected and identified with valid sources. Also, the percentage of changes in the measured characteristics was compared. The results showed that white decay fungi Lenzites betulina and soft decay fungi Annulohypoxylon multiforme appeared on the Bolts. The results of analysis of variance at 95% confidence level, there is a significant difference between the Remaining time and physical and mechanical properties of beet Bolt. According to the results, with increasing storage time in forest, dry and basic density, End an side Hardnesses, Static bending Modulus of Rupture (MOR) and Modulus of Elasticity (MOE) decreased, but the percentage of water absorption increased. The most significant changes in the characteristics of wood were after 12 months of storage in the forest. The greatest change in the physical properties of wood was the percentage of water absorption and lowest was dry density. The greatest change in the mechanical properties of the wood was the Toughness and the least was the modulus of elasticity. This study showed that the quality of beech wood that stored in contact with soil in the forest were reduced due to the activity of destroyer fungi causing white decay and soft decay significantly. the important note was that wood degradation for important properties such as Toughness was 77% after 12 months, which indicates a significant decrease in wood quality and its economic value reduced due to the decrease in density and the weight of Billets And loses its initial performance, So it recommended that wood be transported from forest to the industry in the shortest time possible, so that quality And its economic value, and with a longer durability of wooden products, and fewer tree will be cut off to supply the timber needed for the community and protect forests and environment.