Study On The Variance Of Wood Structure And Properties Of Cornus Wilsoniana

The anatomical properties, chemical properties physical and mechanical properties of Cornus wilsoniana wood have been determined systematically by experiments, analyzed and discussed by means of mathematical statistics in order to seek the wood quality characters and the variance regularity, the results shows as follows:(1).The average of fiber length, fiber width, ratio of length to width, fiber double-wall thickness, ratio of thickness to lumen diameter and ratio of lumen diameter to width were respectively 1634.015μm,14.479μm,114.701,7.467μm,1.099,0.479, the difference of the fiber width, the ratio of fiber length to width, the ratio of fiber double-wall thickness to lumen diameter and he ratio of fiber lumen diameter and width was significant at 0.01 level. After 36 years, the difference of the fiber length and the double-wall thickness among trees is slight, the difference of the other morphology indexes was significant at 0.01 level.The average of vessel length, vessel width, ratio length to width were respectively 1062.042μm,135.119μm,7.979。In 36 years, the difference of the vessel length and the ratio of length to width among trees was significant at 0.01 level, but the vessel width was slight. After 36 years the difference of vessel morphology indexes was slight. (2). The average value of microfibril angle and crystallinity were respectively 25.683°and 58.362°, among the trees, In 36 years, the difference of microfibril angle among trees was obvious, but after 36 years difference was slight, the difference of crystallinity among trees was slight in 36 years and after 36 years. (3). The average value of annual ring width was 1.671mm, the average basic density was 0.755 g/cm3, the difference of annual ring width among trees was slight in 36 years, but the difference was obvious at 0.05 level after 36 years, the difference of basic density among trees was significant at 0.01 level in 36 years, after 36 years, the difference among trees was obvious at 0.1 level. (4). The contents of the cold-water extractive, hot-water extractive, benzene-alcohol extractive, lignin, holocellulose, cellulose were respectively 2.76%,5.53%,3.80%,31.30%,72.27%,42.44%, and the pH value was 5.89. Among the three trees, the difference of lignin content was significant at 0.01 level, the difference of content of hot water extractive, holocellulose, cellulose and pH value was obvious at 0.01 level, while there were slightly differences in the content of cold water extractive and benzene-alcohol extractive at 0.1 level. (5). The air-dried density of wood was 0.896g/cm3; the tangential, radial and tangential oven-dried shrinkage were respectively 9.412%,6.231%,15.330%; the tangential, radial and tangential air-dried shrinkage were respectively 5.709%,3.370%,9.007%; the coefficient of shrinkage was 0.643%; the ratio of tangential shrinkage to radial shrinkage at oven-dried condition and air-dried condition were respectively 1.522,1.707; the tangential, radial and volume swelling from oven-dry to air-dry were respectively 3.571%,2.730%,6.580%; the tangential, radial and volume swelling from oven-dry to wet were respectively 10.346%,6.697%,18.299%; the maximum water-absorbing rate was among 52.86%-75.19%; the compressive strength parallel to grain, bending strength, MOE and toughness of wood were respectively 69.166MPa, 141.646MPa,11.227GPa,116.663KJ/m2; among the trees each physical and mechanical index had significant difference at 0.01 level. (6). The boundary between the juvenile wood and mature wood was around the age of 37～41 year.According to the anatomical indexes, Cornus wilsoniana is not good material of papermaking, but its wood has good physical and mechanical properties, moreover, with the advantages of compactly structure, straight grain, easily process and little deformed, the wood of Cornus wilsoniana can be used as high grade furniture material and decorative material, it also can be used as structure material. The comprehensive results can provide certain scientific bases for the utilization and intensive cultivation of Cornus wilsoniana forests.