tailieunhanh - Báo cáo lâm nghiệp: "Variability in density of spruce (Picea abies [L.] Karst.) wood with the presence of reaction wood"

Tuyển tập những bài báo cáo nghiên cứu khoa học hay nhất được đăng trên tạp chí JOURNAL OF FOREST SCIENCE đề tài: Variability in density of spruce (Picea abies [L.] Karst.) wood with the presence of reaction wood. | JOURNAL OF FOREST SCIENCE 53 2007 3 129-137 Variability in density of spruce Picea abies L. Karst. wood with the presence of reaction wood V. Gryc P. Horácek Faculty of Forestry and Wood Technology Mendel University of Agriculture and Forestry Brno Brno Czech Republic ABSTRACT The study was aimed to assess the integral value that determines wood properties - wood density at a moisture content of 0 and 12 . The wood density was researched in a sample tree with the presence of reaction compression wood. The density was determined for individual zones CW OW SWL and SWR . The zone where compression wood CW is present has a higher density than the remaining zones. On the basis of the acquired data 3D models were created for individual zones they describe the variability of wood density along the stem radius and stem height. The influence of the radius seems to be a statistically highly significant factor. The wood density is significantly higher in samples with the presence of compression wood. When the proportion of compression wood in the sample was 80 the wood density was times higher compared to wood without compression wood. Keywords spruce density compression wood Wood properties are a result of chemical composition and wood structure on all its levels . submicroscopic microscopic and macroscopic ones. Density is considered to be the most significant wood property that also strongly affects the other physical and mechanical wood properties. Therefore it is this physical property that has always been paid the greatest attention. Genetic features species and genus environmental factors soil climatic conditions position mechanical forces such as wind and snow physiological and mechanical effects age tree height form and height of the tree crown position of the tree in the stand operate simultaneously influencing the character and the organization of individual anatomical elements including varying wood density Trendelenburg 1939 . Spruce wood density ranges .