Selected Mechanical Wood Properties of Douglas Fir from Sites in the Czech Republic

Abstract Introduced tree species are still undoubtedly, despite the current short-term politico-economic and environmental turbulences, an object of interest of the Czech forestry sector. Worldwide the most important tree species, and thus both in the areas of its original extension and in the large regions where it was successfully introduced, is the Douglas fir (Pseudotsuga menziesii), which is considered as one of the most perspective tree species. Information about the quality of its wood from our territory is missing for the time being. That´s why the aim of this work was to evaluate the quality of Douglas fir wood from different regions of the Czech Republic through selected mechanical properties. Especially the compressive strength, impact strength, flexural modulus and flexural strength were determined by standardized procedures. As well as, the variability of the trunk features and that one of the locality were taken in consideration. The final results of the mechanical features compared with the values measured on the wood from the original extension areas are better in compression strength, similar in flexural strength and slightly worse in the flexural modulus. Comparing the resultant values of Douglas fir with the values of domestic spruce, the Douglas fir shows better values, apart from the values of flexural modulus, which are higher in case of the spruce. A statistically significant difference between the location and the measured feature is demonstrated only in the elastic modulus and density. At the variability in frame of the trunk there was found a statistically significant difference between the vertical and horizontal position of the trunk and all the measured features. At the same time, the value of the measured feature increases together with increasing position from the pulp