Effects Of Site On Growth And Wood Properties Of Acacia Mangium Plantation

Site is a very signiticant efteet tactor on the growth and wood qualities ot trees. For realizing oriented cultivation of forest, it is necessary to research the rule ot the effect of site on the growth and wood properties of trees. 6 year-old and 13-year-old A. mangium plantation were served as research subjects in this paper. The effect of site on the growth and wood properties of trees was analyzed based on investigation and research as well as wood properties lest in the laboratory.The effect of site on the growth of 6-year-old A. mangium plantation was studied in this research. The results showed that soil type, slope shape and stand density have signiticant effects on the growth of 6-year-old A. mangium plantation while slope direction has no significant effects on that.The effect of site on the basic density and fiber morphology of the wood of 6-year-old.J. mangium plantation was studied in this research. The results showed that the soil type has significant effect on the basic density of the wood of 6-year-old A. mangium plantation. While slope directions, slope shape and stand density have no significant effects on that. The slope direction, slope shape and soil type have significant effects on the fiber width and ratio of length to width, but they have no signiticant effect on fiber length. The stand density has significant effects on the fiber length and diameter, but it has no significant effect on fiber ratio of length lo width.Comprehensive valuation for the growth and wood properties indices of 6-year-old A. mangium plantation in different sites indicated that the integrated characteristic is better on shady slope than that on sunny slope, on coastal sand than on coastal mountain region of stone, on valley than on mountain ridge, in stand density of 750 individual-hm^-2 than in stand density of 1500 individual hm^-2 .Effects of slope direction and soil type on the growth of 13-year-old A. mangium plantation were studied in this research. The results showed that slope direction and soil type-have significant effects on the diameter at breast height, tree height, crown dimension and height of culm with no branches of 13-year-old A. mangiuin plantation. The quantitive matufity age of A. mangtant plantation is about 14 years growing on sllady slope, and it is about 10 years growing on sunny slope. The quantitive ma(?)tity age of.A. mangium plantalion is about (?) years growing in costal sand, and it is about 16 years which growing on mountainous red soil.The effect of slope direction and soil type on the physical and mechanical properties of the wood of 13-year old A. mangium plantation was studied in this research. The results showed that slope direction has significant effects on ratio of tangential shrinkage to radial shrinkage, bending strength, elastic modulus of bending, tangential stiength to cleavage, compression stiength parallel to grain, and has no significant effect on wood air dry density, basic density, coefficient of slniukage, shear strength parallel to grain, hardness, radial strength to cleavage and impact bending toughness. Soil type has significant effects on wood density, coefficients of radial shrinkage, ratio of tangential shrinkage to radial shrinkag, all mechanics indices. It has no significant effects on coefficients of tangential shrinkage and coefficients of volume shrinkage. Wood density, ratio of tangential shrinkage to radial shrinkag and all mechanics indices come from sunny slope are larger than that come from shady slope. And the wood density, ratio ot tangential shrinkage to radial shrinkag and all mechanics indices come from coastal sand arc larger than that come from mountainous red soil.The effect of slope direction and soil type on the wood fiber morphology as well as chemical composition of the wood of 13-year-old A. mangium plautalion was studied in this research. The results showed that the slope direction has significant effects on fiber width and ratio of wall to lumen, and has no significant effects on fiber length, ratio of length to width, lumen diameter of fiber and double wall thickness. The soil type has significant effects on fiber width and ratio of wall to lumen, and has no significant effects on other indices of (?) mo(?)phology. Contents of cellulose and extractive of A. mangium wood from plantation growing on sunny slope are bigger than that growing on shady slope, while the ash and lignin content smaller. The content of cellulose of A. mangium wood from plantation growing on mountantnous red soil is bigger than that growing in coastal sand, while the ash, lignin content and extactive smaller. Used as fiber material, the technical matu(?)ity age of A. mangium plantation growing on shady slope is 9 years, while the one growing on sunny slope is 11 years. The technical mu(?)y age is 10 years which grow on coastal sand, and it is11 years which grow on mountainous (?)d soil.Comprehensive valuation indicates that the wood of 13 year-old A mangium plantation which grow on mountainous red soil is more suitable for pulpwood than that grow on coastal sand. And the one growing on coastal sand is more suitable for construction finber.The wood of 13-year-old A. mangium plantation which grow on sunny slope is not only suitable for pulpwood, but also suitable for construction timber. Proportion of juvenile wood of A. mangium planted on shady slope and coastal sand is small. On the basis of analysing vatiation (?)e of wood properties and effects of sites on wood properties, a better cultivation pattern for A. mangium plantation used for construction timber or pulpwood was built in this paper.