Studied Wood Fiber Variation Of Differet Tree Age Of Acacia Mangium In The Gaofeng Forestry

Based on 20 years old, 12 years old, 7 years old and 4 years old of Acaciamangium in Gaofeng Forestry Center in Guangxi province, wood fiberelement dimensions of different tree age of the normal trees andcompression trees' fiber morphological characteristics,microfibriilar angleand wood fiber proportion of tracheid are identified. The results showthat:(1) Fiber morphological characteristics:①the radial variation rule ofwood fiber length is:length raises with the increase of tree age, its variationscope is 622.92～1242.50μm; the longitudinal variation wood fiber length is:length raises with the increase of tree height (from 1.3m), its variation scopeis 636.21～1121.55μm.②the radial variation rule of wood fiber diameter is:length descends with the increase of tree age, its variation scope is 19.80～29.36μm; the longitudinal variation of wood fiber diameter is: length raiseswith the increase of tree height (from 1.3m), its variation scope is 21.39～26.40μm.③the radial variation rule of wood fiber thickness of cell wall is: length raises with the increase of tree age, its variation scope is 4.09～8.96μm; the longitudinal variation of wood fiber thickness of cell wall is:length descends with the increase of tree height, its variation scope is 4.05～9.72μm.④the radial variation rule of wood fiber ratio of length to diameteris: length raises with the increase of tree age, its variation scope is 22.22～58.62;the longitudinal variation of wood fiber thickness of cell wall is:length raises with the increase of tree height, its variation scope is 26.53～51.38.⑤the radial variation rule of wood fiber ratio of cell wall to cavity is:length raises with the increase of tree age, its variation scope is 0.22～1.02;the longitudinal variation of wood fiber ratio of cell wall to cavity is :length descends with the increase of tree height, its variation scope is 0.17～0.90.(2) The results of variance analysis show that: The redial variation ofthe wood fiber length, diameter and ratio of length to diameter of normaltrees are marked differences among different tree age. The cell wall widthof normal trees of different trees age years are remarkable, diameter andratio of length to diameter of normal trees and compression trees of 4 yearsare remarkable, Other are insignificant. There are marked differences in thelongitudinal variation of different tree age of normal trees of wood fiberlength, diameter, cell wall width, ratio of length to diameter, thickness of cellwall, other are insignificant.(3) The radial variation rule of microfibrillar angle is:length descends with the increase of tree age, its variation scope is 13.0～22.9°, the averagevalue is 18.85°, There are marked differences in microfibrillar angle amongdifferent tree age.(4) The redial variation of proportion of tracheid is:length descendswith the increase of tree height, its variation scope is 84.74%～93.39%, theaverage value is 89.09%, the correlation coefficient is 0.889. proportion oftracheid is insignificant among different tree age.(5) The boundary between juvenile wood and mature wood was theseventh years.