Junji Matsumura

Conducting Pathways in North Temperate Deciduous Broadleaved Trees

The interspecific variation of dye ascent in the stems of 44 broadleaved deciduous species growing in Japan was studied using freeze-dried samples after dye injection. The dye ascending pattern differed both within and between ring-porous and diffuse-porous species. In large earlywood vessels of all ring-porous species, the dye ascended only in the outermost annual ring, and the inner annual rings had lost their water transport function. The dye ascending pattern within the inner annual rings in the ring-porous species was categorized into three types: i) the dye ascended both in the many latewood vessels throughout the latewood and small earlywood vessels; ii) the dye ascended in the many vessels throughout the latewood; and iii) the dye ascended mainly in the late latewood vessels. In diffuse-porous species, the dye ascending pattern within the annual rings also was categorized into three types: i) the dye ascended throughout the annual rings; ii) the dye ascended mainly in the earlywood vessels; and iii) the dye ascended mainly in the latewood vessels. Xylem water distribution was also examined by cryo-SEM in three ring-porous and three diffuse-porous species that had different dye ascending patterns. The water distribution pattern within annual rings was correlated with the dye ascending pattern except for one diffuseporous species (Salix gracilistyla). In this case, water was distributed in the whole region of the annual rings although dye was mainly distributed in the earlywood. These results showed that the functional area of water transport within annual rings differed among ring-porous species and diffuse-porous species.

Effect of wood properties on within-tree variation in ultrasonic wave velocity in softwood

The radial variations in the velocity of longitudinal waves propagating through Japanese cedar and Japanese cypress were experimentally investigated. In addition, the tracheid length (TL), microfibril angle (MFA), air-dried density (AD), and moisture content (MC) were measured in order to determine the effect of wood properties on velocity variations within the wood trunk. For both species, the longitudinal wave velocities measured in the longitudinal direction (V(L)) exhibited minimum values near the pith. For Japanese cedar, V(L) increased from 3600m/s toward the bark and soon attained a constant value (=4500m/s). On the other hand, for Japanese cypress, V(L) kept increasing from 4000m/s near the pith to 4800m/s at the bark. These radial variations in V(L) coincided with those in the tracheid length. V(L) exhibited strong correlations with TL and MFA with a significant level of (p<0.01). These findings suggest that the TL and MFA greatly affect the radial variation in the ultrasonic wave velocity in softwood.

The effect of planing on the microscopic structure of Pinus radiata wood cells in relation to penetration of PVA glue

Pinus radiata wood cells and penetration of PVA glue was examined by light microscopy and scanning and transmission electron microscopy. After planing with dull knives the wood cells were greatly distorted and cell walls were extensively damaged, particularly at and near the glue line. In comparison, sharp knives caused much less damage to cell walls and the cells had a normal or near-normal appearance. These features are discussed in detail in relation to glue penetration and the performance of glue joints after planing with sharp and dull knives.Pinus radiata Holzzellen und das Eindringen von PVA-Kleber wurde mit Licht- Raster- und Transmissionselektronen-Mikroskop untersucht. Nach dem Hobeln mit stumpfen Messern waren die Holz-zellen sehr verzogen und die Zellwände weitgehend beschädigt, insbesondere an und nahe der Leimfuge. Im Vergleich dazu haben scharfe Messer viel weniger Schaden an den Zellwänden angerichtet und die Zellen hatten eine normale bzw. fast normale Erscheinung.Diese Merkmale werden detailliert in Bezug zur Leimpenetration und der Haltbarkeit der Leimfugen nach dem Hobeln mit scharfen und stumpfen Messern diskutiert.

Xylem water-conducting patterns of 34 broadleaved evergreen trees in southern Japan

A dye injection method was used to elucidate the xylem water-conducting pathways of 34 broadleaved evergreen trees growing in southern Japan: two semi-ring-porous, 26 diffuse-porous, five radial-porous and one non-vessel species. The large earlywood vessels in semi-ring-porous species have a water transport function in only the outermost annual ring, as in deciduous ring-porous species. On the other hand, the small vessels in semi-ring-porous species maintain the water transport function in many outer annual rings. For the other xylem-type species, the many vessels in many outer annual rings have a water transport function. In diffuse-porous species, we categorized the water-conducting pattern within the annual rings into two types: d1 type, where water travels through vessels in the whole region; and d2 type, where water travels mainly through the earlywood vessels. The pattern in radial-porous species is similar to that in the d1 type; the pattern in non-vessels species is similar to that in the d2 type. The vessel diameter in radial-porous species is similar to that of the earlywood vessels of semi-ring-porous species. These results suggest that the conduit diameter size is only one of many factors determining the water-conducting pathways of broadleaved evergreen species.

Variation in wood properties of six natural acacia hybrid clones in northern Vietnam

Wood properties of six 8-year-old natural acacia hybrid clones between Acacia mangium and Acacia auriculiformis, planted in Bavi, Vietnam, were studied. The hybrid clones possessed obvious heterosis in growth and in some wood properties. The characteristics of growth, air-dry specific gravity, lengths of fibers and vessel elements, S2 microfibril angle, green moisture content, and shrinkage were examined to clarify the variation among clones. From the results, the differences among the clones in growth and in some wood properties were significant. The pattern of distribution of specific gravity showed that there were low and high specific gravity zones in the stem. Specific gravity at stump height or at 3.0 m was useful for prediction of specific gravity in the whole tree stem. Moreover, clones with high specific gravity can be predicted at a young age. There was no significant correlation between diameter growth and specific gravity. Of the six clones studied, clone BV5 was selected as the best based on its growth ability and specific gravity.

Shrinkage of tracheid cells with desorption visualized by confocal laser scanning microscopy

Confocal laser scanning microscopy (CLSM) was applied as a new method of visualizing the shrinkage of wood and its anisotropy. Control of relative humidity and temperature in a specialized environment chamber made it possible to acquire transverse images of tracheids of Akamatsu (Pinus densiflora) from the saturated condition to the dried condition. The shrinkage of tracheid cells was also determined by measuring the tangential diameter of tracheid and lumen, the radial diameter of tracheid and lumen, and the thickness of tangential and radial walls. Moreover, this technique makes it possible to discuss the relationship between moisture content and tracheid cell shape. We found the CLSM technique to be an effective method for visualizing shrinkage of tracheid cells with desorption.

Impregnation of radiata pine wood by vacuum treatment. II: Effect of pre-steaming on wood structure and resin content

Radiata pine sapwood and heartwood were dried using high-temperature, conventional-temperature, and air drying schedules with and without pre-steaming. They were then impregnated by vacuum treatment with double-distilled water, toluidine blue, and fluorescein dye. For sapwood, there were only minor differences in uptake between drying methods and when pre-steaming was used. Using microscopy, the primary flow pathways in sapwood were found to be the resin canal network and ray parenchyma cells, which provided conduction without large resistance. In heartwood, uptake was strongly influenced by pre-steaming the green lumber. After pre-steaming heart-wood, there was an increase in uptake from all surfaces but especially from the radial surfaces. Lower extractive contents, disruption of epithelial and ray parenchyma cells, and alteration of the condition of bordered pits were also associated with pre-steaming. It was therefore possible to classify flow paths in radiata pine heartwood five ways, according to uptake values and wood anatomical features.

Impregnation of Radiata Pine Wood By Vacuum Treatment: Identification of flow Paths Using Fluorescent Dye and Confocal Microscopy

Radiata pine sapwood and heartwood were dried with or without presteaming and then impregnated by vacuum treatment with water, toluidine blue and fluorescein. Sapwood uptake was 0.571 g/cm3 and was not affected by pre-steaming. As expected, the uptake by heartwood that had not been pre-steamed was very low. Pre-steaming increased liquid uptake from 0.113 g/cm3 to 0.438 g/cm3. When the uptake by pre-steamed heartwood from radial, tangential and transverse surfaces was compared, the greatest increase was from the radial surfaces, suggesting that pre-steaming of heartwood resulted in changes to the tangential liquid flow pathways. The liquid flow pathways in sapwood consisted ofaxial and radial resin canals, ray parenchyma cells in both fusiform and uniseriate rays. Penetration into tracheids was also observed. Without pre-steaming, there was limited liquid flow into heartwood, and this was generally confined to resin canals and ray parenchyma. Pre-steaming of heartwood increased penetration of dye into the resin canal network, presumably due to removal or redistribution of resin. Fluorescein was also evident in bordered pits between tracheids, suggesting that one of the ways that pre-steaming increased heartwood treatability was by altering the condition ofbordered pits to allow greater conduction. The combination of fluorescein dye and confocal microscopy was found to be a particularly effective way of visualising flow patterns, as it was possible to examine thick sections, which avoided microtome damage at the section surface. Examination of dry wood also minimised the possibility of dye redistribution.

Possibility of improvement in fundamental properties of wood of acacia hybrids by artificial hybridization.

Growth, specific gravity, and wood fiber length of Acacia mangium, Acacia auriculiformis, artificial acacia hybrid clones, and combinations, which were planted in a trial forest in Bavi, Vietnam, in July 2001, were examined. The radial variations from pith to bark were investigated to clarify the effect of genetic factors on these traits. Superiority of hybrids over their parents ranged from 36.3% to 41.6% for diameter, from 20.0% to 25.3% for height, from 6.9% to 20.7% for specific gravity, and from 6.1% to 12.8% for wood fiber length. The hybrid possessed heterosis in diameter, height, specific gravity, and wood fiber length regardless of whether the female parent was A. mangium or A. auriculiformis. The profiles of wood fiber length and specific gravity in the radial direction were similar for all the trees investigated. Wood fiber length was initially 0.5–0.6 mm near the pith and then increased slowly, finally reaching 1.0–1.2 mm near the bark. The specific gravity of acacia increased from 0.49–0.58 near the pith to 0.63–0.74 near the bark. From a relative distance of 30% from the pith, the specific gravity increased slightly and seemed to be stable. The relations among tree diameter, specific gravity, and wood fiber length were fair and could be represented by positive linear regression formulas. Hybrids for which A. auriculiformis was the female parent and A. mangium was the male parent had a faster growth rate and longer wood fibers than the inverse hybrids.

X-ray microanalysis using thin sections of preservative-treated wood: Relationship of wood anatomical features to the distribution of copper

The objective of this study was to understand the micro-distribution of a copper-based preservative in wood in connection with anatomical morphology and to consider the fixation of copper in wood. Bulk specimens and semi-ultra thin sections (0.5 μm) obtained from Japanese cedar (Cryptomeria japonica) were treated with a CuAz preservative solution. After fixation of the solution in wood components, SEM-EDXA (Scanning Electron Microscope equipped with an Energy Dispersive X-ray Analyzer) was used to investigate the micro-distribution of copper. The use of semi-ultra thin sections improved characteristic X-ray spatial resolution and made it possible to analyze the micro-distribution of copper. In both earlywood and latewood of the sapwood, copper was more abundant in the compound middle lamella than in the secondary wall and concentrated in the tori. Copper was most concentrated as crystalline deposits in longitudinal parecnhyma cells. Semi-quantitative analysis revealed the copper amount to increase in this order: secondary wall in tracheids < middle lamellae < membrane of half-bordered pits < tori in tracheid pits < deposits in longitudinal parenchyma cells. These different concentrations may indicate significant interactions between the amine-copper complex in CuAz and chemical constituents of wood.