Effect of support on the growth of a woody vine,Wisteria floribunda DC. (Leguminosae)

Seedling ofWisteria floribunda, which belongs to the twiner type of climbing plants, were planted in nursery and the effect of support on the growth of the seedlings was tested. The seedlings were grown with 240 cm-height and 120 cm-height supports (the culms of a dwarf bamboo), and without support. Positive effect of the supports and its length were observed for stem length ofW. floribunda at the end of the growing season. The positive effect of support was also observed for total dry weight. Total dry weight with 240 cm-height support reached more than the double of the seedlings without support. These effects of the support were attributed to die-back behavior of the twining stem, which detached from the support or did not encounter the support. Diameter of the stems without support showed a rapid decrease toward the stem tip, while that with support were relatively constant when they were twining around the support. The existence of the support also affected the dry matter allocation in this species; supported seedlings allocated larger proportion of biomass to current-year stems than unsupported seedlings, although the allocation to the roots was smaller in the supported treatments. Support availability may be critical for the establishment and further growth of the seedlings ofW. floribunda which regenerate at the forest edge and canopy gaps. A part of this report was presented at the 107th Annual Meeting of the Japanese Forestry Society, at Tsukuba, April, 1996.     

Diurnal changes in the partial pressure of carbon dioxide in coral reef water

Coral reefs are considered to be a source of atmospheric carbon dioxide because of their high calcium carbonate production and low net primary production. This was tested by direct measurement of diurnal changes in the partial pressure of carbon dioxide (Pco(co2)) in reef waters during two 3-day periods, one in March 1993 and one in March 1994, on Shiraho reef of the Ryukyu Islands, Japan. Although the Pco(co2) values in reef waters exhibited large diurnal changes ranging from 160 to 520 microatmospheres, they indicate that the reef flat area is a net sink for atmospheric carbon dioxide. This suggests that the net organic production rate of the reef community exceeded its calcium carbonate production rate during the observation periods.     

Characterization of genes for novel thaumatin-like proteins in Cryptomeria japonica

Thaumatin-like proteins (TLPs) are induced by a variety of phytopathogens in many plants and several TLPs are allergenic. Previously, we isolated three TLP-encoding cDNAs (Cry j 3.1, Cry j 3.2 and Cry j 3.3) from a cDNA library derived from the pollen of Cryptomeria japonica D. Don. Here, we describe three new TLP cDNAs (Cry j 3.4, Cry j 3.5 and Cry j 3.6). We compared the sequences, the genetic map location and the expression patterns of the Cry j 3 genes. The amino acid sequence predicted from Cry j 3.5 exhibits only limited similarity to those predicted from the other Cry j 3 genes. Linkage analysis showed that the Cry j 3.1 to Cry j 3.4 genes are located in the same linkage group, but Cry j 3.5 is located in a different group. Organ-specificity and induction by stresses and plant hormones differed among the Cry j 3 mRNAs. In pollen grains, the Cry j 3.5 mRNA expression level was higher than that of the other Cry j 3 genes. Exposure to UV-B and salt stress induced expression of Cry j 3.1. The ethylene-releasing compound ethephon strongly induced expression of Cry j 3.4. Salt stress and salicylic acid also induced expression of Cry j 3.4. Abscisic acid weakly induced expression of Cry j 3.5. Arachidonic acid strongly induced expression of Cry j 3.4 and Cry j 3.6, and weakly induced that of Cry j 3.3, whereas expression of Cry j 3.1 and Cry j 3.5 was unaffected. These results suggest that the roles of TLPs and the cascades that regulate their expression differ among the members of the TLP family in C. japonica.     

Airborne laser scanning in forest management: Individual tree identification and laser pulse penetration in a stand with different levels of thinning

This study examined the ability of an airborne laser scanner to identify individual trees in the canopy of a Chamaecyparis obtusa stand and investigated the relationship between the penetration rate of the laser pulses and stand attributes under different canopy conditions caused by different levels of thinning. Individual tree crowns were identified from a digital canopy model (DCM) derived from airborne laser scanner data by the watershed segmentation method. The identification rate of individual trees in blocks with heavy thinning (ratio of the basal area of the felled trees to the total basal area, hereinafter thinning ratio of the basal area, 38.0%), moderate thinning (30.4%), and no thinning was 95.3%, 89.2%, and 60.0%, respectively. Individual tree heights were estimated from the DCM values by local maximum filtering within identified individual crowns. Tree height in the three blocks was estimated with a root-mean-square error of 0.95, 0.65, and 0.68 m, respectively. Tree heights determined in a field survey were regressed against those estimated from the DCM, yielding coefficients of determination (r²) of 0.71, 0.87, and 0.85, respectively, for the blocks with heavy thinning, moderate thinning, and no thinning, respectively, and 0.86 overall. The respective penetration rates of the laser pulses through the canopy to the ground were 50.6%, 43.1%, and 9.2%. Regression of the laser pulse penetration rate against the thinning ratio of the basal area and against the total basal area of the remaining trees in 25 quadrats established in the blocks, yielded r² values of 0.89 and 0.74, respectively.     

Effect of particle shape on linear expansion of particleboard

Hinoki (Japanese cypress) strand with 0.6mm thickness was hammer-milled to prepare three types of particles that had the same thickness but different lengths and widths. Screen analysis and image analysis were conducted to evaluate the shape and distribution of the particle dimensions. Laboratory-scale particleboards were fabricated at three density levels using these particles. To determine the true effect of particle shape on the linear expansion (LE) of the board, these boards exhibited almost the same temperature behavior during pressing, the same density profile, and the same bending properties at each board density level. LE at 40°C and 90% relative humidity of the board was found to be affected by the particle shape. The board composed of small particles showed a larger LE at the same density level. It was considered that the out-of-plane orientation angle of the particles affected the LE of the boards. Thickness swelling and internal bond strength were also affected by the particle shape.Part of this report was presented at the 50th annual meeting of the Japan Wood Research Society, Kyoto, April 2000     

New lignan, isoactifolin, fromChamaecyparis obtusa cv. Breviramea

A new lignan isoactifolin was isolated from young shoots (with leaves) ofChamaecyparis obtusa cv. Breviramea. The structure of the compound was determined based on spectroscopic evidence.Parts of this report were presented at the 44th lignin symposium, Gifu, October 1999     

Evaluating the durability of wood-based panels using internal bond strength results from accelerated aging treatments

In this study, the durability of wood-based panels was evaluated by comparing the internal bond (IB) strength retention after five different laboratory-based accelerated aging tests with the IB retention after 5 years of outdoor exposure in Shizuoka City. In each accelerated aging test, the IB retention of MDI-bonded panels showed high retention compared to other panels. Outdoor exposure in Shizuoka City resulted in an IB retention value for particleboard (PF) and oriented strandboard (aspen) of less than 10% after the 5-year exposure period. Medium-density fiberboards maintained their initial IB strength over the same period. Calculation of the mean IB retention for all board types allowed comparison of the severity of aging between the accelerated test methods and outdoor exposure. The ASTM six-cycle test method was the most severe among the standard treatment cycles applied.     

Nickel-catalyzed carbonization of wood for coproduction of functional carbon and fluid fuels I: production of crystallized mesoporous carbon

Japanese larch wood loaded with nickel (1%–4%) alone or with nickel and calcium (0.25%–1.5%) was carbonized at 800°–900°C for 0–120min with a heating rate of 5°–20°C min⁻¹ in a helium flow of 5.8−46.4 ml STP cm⁻² min⁻¹ to examine the influence of these variables on the crystallization of carbon (the formation of T component) and the development of mesoporosity. From the obtained results, reaction conditions suitable for effective production of carbon with the dual functions of adequate electroconductivity and adsorption capacity in liquid phase were established, thereby explaining the factors that govern the process. It was also confirmed that mesopore having a diameter of about 4 nm was selectively produced at the cost of specific (BET) surface area in parallel with the formation of T component. This result provided good insight into how the simultaneous dual function could be realized.     

Lignan production inDaphne odora cell cultures

Lignan production in callus and cell suspension cultures ofDaphne odora is reported for the first time. The cell suspension culture produced pinoresinol, lariciresinol, secoisolariciresinol, matairesinol, and wikstromol. The production of matairesinol in the cell suspension culture was much higher than that inDaphne odora stem tissues.Part of this report was presented at the 51th annual meeting of the Japan Wood Research Society, Tokyo, April 2001