2016 年 25 巻 1 号 p. 23-31
The growth characteristics, anatomical characteristics, and wood properties of Dysoxylum mollissimum, a fast-growing tree species, were investigated. To clarify the effect of radial growth rate on these characteristics and properties, 10-year-old trees planted in Bengkulu, Indonesia were examined and classified into three categories (fast-, medium-, and slow-growing). Xylem maturation type was also evaluated in this species. The mean values of stem diameter, tree height, stem volume, and stress-wave velocity in the 50 measured trees were 18.0cm, 10.6m, 0.119m3, and 3.48km s-1, respectively. Mean values of anatomical characteristics and wood properties in nine selected trees were as follows: vessel diameter, 129µm; vessel frequency, 3.5 vessels mm-2; cell wall thickness of wood fiber, 1.2µm; percentages of vessels, wood fiber, ray parenchyma, axial parenchyma, and cell wall, 8.8, 72.9, 12.4, 5.9, and 33.5%, respectively; vessel element length, 0.36mm; wood fiber length, 1.04mm; basic density, 0.45g cm-3; and compressive strength parallel to the grain in green condition, 29.9MPa. These obtained values were similar to or smaller than previous results obtained in research on other Dysoxylum spp. For almost all of the anatomical characteristics and wood properties, no significant differences among the categories were found. This suggests that the trees with faster radial growth characteristics do not always produce lower quality wood in this species. Judging from the radial variation of anatomical characteristics, the xylem maturation of this species depends on the diameter growth, and it might occur at around 6 to 8cm from the pith.
