In this master`s thesis the anatomical and micromechanical properties of Douglas fir wood (Pseudotsuga menziesii L.) were investigated as a function of the radial position and the development zones (juvenile wood, adult wood, sapwood, heartwood). The microscratching method was used to determine the hardness of the wood on a microscopic level, i.e. its resistance to the penetration of a sharp tip into its structure. The greatest penetration depth was found in juvenile wood and sapwood. In juvenile wood this result is attributed to the thinner cell walls, whereas in sapwood to the lower content of extractives and, consequently, to the lower wood density. The higher resistance to tip penetration in mature wood and heartwood indicates a higher density and better mechanical properties of this wood. The decreasing relationship between the width of the annual rings and the penetration depth (Δx/ΔPd) reflects changes in porosity and mechanical properties with the age of the tree. It was found that higher temperatures and lower precipitation negatively affect wood increment. Statistical analysis confirmed the relationship between micromechanical wood properties and site-specific growth conditions. The findings contribute to a better understanding of the effects of climatic factors on wood formation in Douglas fir, and support its future application in the wood processing industry.
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