The Effect of Different Relative Humidity Conditions on Mechanical Properties of Historical Fir Wood Under the Influence of Natural Aging

Wood undergoes degradation and aging due to various physical and biological factors throughout its lifespan. Among these factors, environmental conditions such as relative humidity, temperature, rainfall, and UV radiation play a crucial role in the physical, chemical, and biological deterioration of wood. In this study, the effects of relative humidity on the density, bending strength, and compressive strength of wood were investigated. Fir beam elements from a traditional wooden structure, estimated to be approximately 150 years old, and freshly cut fir wood specimens were tested under relative humidity conditions of (30 ± 5) %, (65 ± 5) %, (85 ± 5) %, and (95 ± 5) % at a temperature of (20 ± 2) °C. A one-way ANOVA analysis was conducted to evaluate the effects and interactions of different relative humidity conditions on density, bending strength, and compressive strength for both naturally aged fir and freshly cut fir specimens. The results indicate that naturally aged fir wood exhibits greater stability in terms of density; however, strength loss is more pronounced under high relative humidity conditions. These findings suggest that natural aging has a significant impact on the preservation of wooden structures with historical and cultural value and contribute to a better understanding of such structures.