Kazuya Iizuka

Variation in the Wood Properties of Paraserianthes Falcataria Planted In Indonesia

In many tree breeding programs, plus trees have been selected according to growth rate or stern form in trees. Trees that have a high growth rate or good stern form do not always produce industrially desirable wood. Therefore criteria for wood quality should be considered in tree breeding programs. The objective of this study is to obtain the basic knowledge for breeding for wood quality in Paraserianthes falcataria, an important commercial tree species of Indonesia. Variation in the growth, log properties, basic density, and fiber length in 13-year-old P. falcataria was investigated. Even though all trees were the same age, diameter at breast height showed high variation, indicating a significant variance in the growth rate of seedlings. Significant differences in the log properties (green density, dynamic Youngs modulus, and stress-wave velocity) were observed among the trees. Basic density showed a constant value up to 10 cm from pith, at which point it began to increase. The fiber length increased up to 10 cm from the pith and then showed an almost constant value. According to the radial variation of the basic density and fiber length, wood is categorized as core wood, which includes that up to 10 cm from the pith, and outer wood, which is that from 10 cm to the bark. In addition, a significant difference in the basic density of core wood was observed among the trees, indicating that the selection of a plus tree with high-density wood in this species is possible at a relatively early stage. These results indicate that the wood quality in P. falcataria can be improved through tree breeding.

RADIAL VARIATION OF ANATOMICAL CHARACTERISTICS IN PARASERIANTHES FALCATARIA PLANTED IN INDONESIA

Radial variation in anatomical characteristics of five 13-year-old Paraserianthes falcataria (L.) Nielsen (syn. Albizia falcataria (L.) Fosberg), an important commercial tree species in Indonesia, were investigated in order to obtain basic information regarding breeding for wood quality. Both cell wall thickness in wood fibers and vessel percentage showed an almost constant value up to 10 cm from the pith and then increased toward the bark. In contrast, wood fiber percentage decreased from 10 cm toward the bark. The cell wall percentage was lower towards the pith and higher towards the bark. In the five sample trees, significant differences were found in the cell diameter of wood fibers, wood fiber percentage, axial parenchyma percentage, and cell wall percentage. Basic density was affected by the cell wall thickness of wood fibers, but not the vessel percentage and fiber percentage.

Wood Quality of Sugi (Cryptomeria Japonica) Grown at four initial Spacings

Wood quality is affected by silviculture, which includes factors such as stand density control and genetics. In the present study, the effects of initial spacing on the general wood quality and lumber quality of sugi wood (Cryptomeria japonica D. Don) were examined. Logs of 35-year-old sugi were cut from four stands with different initial spacing (A: 2.6 by 2.6 m, 1,500 trees/ha; B: 1.8 by 1.8 m, 3,000 trees/ha; C: 1.3 by 1.3 m, 6,000 trees/ha; D: 1.0 by 1.0 m, 10,000 trees/ha). Trees from stand A showed significantly larger values in annual ring width than trees from the other stands. However, there were no significant differences in the wood basic density, the length of latewood tracheids, and the microfibril angle of the S2 layer among stands. On the other hand, initial spacing affected the lumber quality. The average diameter of knots was significantly larger in stand A than in the other stands. In addition, the dynamic Youngs modulus, the modulus of rupture, and the modulus of elasticity in static bending increased with the decrease in the initial spacing from 2.6 by 2.6 m to 1.3 by 1.3 m.

Radial variations of wood properties in Casuarina equisetifolia growing in Bangladesh

Radial variations of wood properties (basic density, fiber length, vessel element length, and compression strength) in plantation-grown Casuarina equisetifolia in Bangladesh were investigated for effective utilization of the wood. Samples disks at breast height were randomly collected from trees in a 10-year-old plantation in Cox’s Bazar Forest Division, Bangladesh. The basic density showed a near-constant value up to 30 mm from the pith and then rapidly increased up to 60 mm from the pith. The fiber length and vessel element length gradually increased from the pith to bark. When radial variation of wood properties was determined according to relative distance from the pith, similar radial patterns were observed among the sample trees, indicating that the wood properties in C. equisetifolia may be related to the growth rate. The compression strength parallel to the grain (CS) increased from the pith to bark. A significant positive correlation was found between the air-dried density and the CS. The results obtained indicated that wood around the pith has a relatively low density, and wood outside the pith area has a relatively high density, suggesting that it could be used as structural lumber.

Relationship between Resistance to Vole Browsing and Content of Ether Extract in the Bark of Larch Species and Hybrids

We determined the survival rate of tree families produced by the intra- and interspecific crossing of larch species damaged by browsing of vole (Clethrionomys rufocanus bedfordiae Thomas) and the contents of ether extracts (EE) in their bark. The average survival ofLarix gmelini var.japonica Pilg. (L. gmelini)×L. gmelini (G×G) was highest, followed by the hybridL. gmelini×L. leptolepis Gordon (G×L). The families of the hybrid G×L, which is considered suitable for silviculture in Hokkaido, Japan, showed significant differences in survival rates, suggesting that it is possible to produce improved varieties of the hybrid which are more resistant to vole browsing. The EE contents of the bark were under strong hereditary control, and the rank of the EE content among the various families hardly fluctuated between the location of the test fields. The correlation coefficient between the survival rates and the EE contents was highly significant (r=0.89,n=24,p<0.01), indicating that the EE content in the bark may be used as a possible index of resistance or susceptibility to vole browsing in larch plantations.

Wood properties of Pericopsis mooniana grown in a plantation in Indonesia

The relationships between growth characteristics and wood properties were investigated for a threatened species, Pericopsis mooniana, to promote the establishment of plantations of this species in the tropics. Growth characteristics (diameter and height) and stress-wave velocity (SWV) of trees were measured for 22-year-old P. mooniana trees planted in Indonesia. The trees were categorized into three groups, fast-growing, middle-growing, and slow-growing trees, to investigate the effect of growth rate on the wood properties. In addition, radial variation of anatomical characteristics and wood properties were determined. No significant correlation was found between growth characteristics and SWV. The values for the vessel diameter, cell wall thickness of wood fibers, wood fiber length, basic density, modulus of elasticity, and modulus of rupture from wood at the bark side were higher than those at the pith side. On the other hand, vessel frequency gradually decreased from pith to bark. These results suggested that low-quality wood, such as juvenile wood, existed near the pith area.

Wood Properties of Young Acacia mangium Trees Planted in Indonesia

Abstract This study evaluated the wood properties of 5- and 7-year-old Acacia mangium trees planted in West Java, Indonesia. A plot (20 by 20 m) was selected in each stand. The stem diameter and stress-wave velocity (SWV) were measured for all trees (n = 24 and 18 for 5- and 7-y-old trees, respectively) in the plots. Core samples were taken from all trees in each plot using an increment borer to measure the basic density (BD) and compressive strength parallel to the grain (CS). The mean ± standard deviation stem diameter was 13.1 ± 3.0 and 21.9 ± 3.8 cm in 5- and 7-year-old trees, respectively. There was no significant correlation between stem diameter and SWV. The mean BD and CS for 5-year-old trees were 0.42 ± 0.02 g cm−3 and 30.0 ± 4.4 MPa, respectively, and for 7-year-old trees were 0.45 ± 0.02 g cm−3 and 32.8 ± 3.6 MPa, respectively. There was a positive correlation between BD and CS in 5- and 7-year-old trees (r = 0.790 and 0.583, respectively). The radial variation patterns for BD and CS were simil...

Cesium absorption through bark of Japanese cedar (Cryptomeria japonica)

Absorption of radiocesium (137Cs and 134Cs) through bark, and its subsequent translocation into wood and needles, has been suggested as a potential source of tree contamination, but the process is not well understood. Field experiments were conducted to confirm whether Cs could enter a Japanese cedar tree through the bark and how Cs moves within a tree. Stable Cs (133Cs) was applied to the bark at 1.2-m height on 10- and 26-year-old Japanese cedars. The 133Cs concentrations were determined in the bark, sapwood, and heartwood (for 26-year-old cedar only) of stem disks from several heights, as well as in current-year needles from the canopy. The 133Cs concentrations were considerably higher in the sapwood and heartwood of stem disks from 1.2-m height in treated trees than in untreated trees, suggesting that 133Cs penetrated the bark to enter the wood. The average 133Cs concentrations were higher in the heartwood than the sapwood, indicating 133Cs accumulation in the heartwood. High 133Cs concentrations in the needles of treated trees implied acropetal movement of 133Cs to actively growing organs. Our results demonstrate that Cs can enter Japanese cedar trees through the bark and that Cs is transported radially to the heartwood and vertically to the apex.

Cell Morphology and wood properties of Shorea Acuminatissima Planted in Indonesia

In view of the importance of long-rotation plantation forestry in SE Asia to limit soil erosion, the cell morphology and wood properties of 35-yearold plantation trees of yellow meranti, Shorea acuminatissima Sym. were studied. To understand the effects of growth rate on cell morphology and wood properties, 131 trees in a stand were classified according to their stem diameter as fast-, medium-, and slow-growing. Five trees in each category were selected for determining the cell morphology and wood properties. There were significant differences in vessel diameter, vessel frequency, and cell wall thickness of wood fibers in the three categories. The fast-growing trees had a relatively low frequency of wide vessels and thick-walled wood fibers. However, no significant differences in basic density or compressive strength parallel to grain were identified in the three categories. The radial variation in the cell morphology and wood properties showed an almost identical pattern in the three categories, suggesting that xylem maturation depends on the cambial age rather than growth rate.

Physical and Mechanical Properties of Woods from Three Native Fast-Growing Species in a Secondary Forest in South Kalimantan, Indonesia

Abstract Growth characteristics and basic wood properties of three native fast-growing species, terap (Artocarpus elasticus Reinw. ex Blume), medang (Neolitsea latifolia (Blume) S. Moore), and bali...