Effects of insect predation on hypocotyl survival and germination success of maturequercus variabilis acorns

The rates of hypocotyl and radicle survival and of germination success were investigated in mature acorns ofQuercus variabilis Blume in relation to endosperm loss due to seed insects. The acorns were damaged by curculio weevils (Coleoptera: Curculionidae) and moths, including tortricid moths (Lepidoptera: Tortricidae); the former were more abundant than the latter. Acorns damaged by curculio weevils showed a significantly lower germination rate when there was a large endosperm loss than the rate for sound acorns. The survival rate of the hypocotyl and radicle also decreased as endosperm loss increased. These results suggest that acorn germination is directly inhibited by damage to the hypocotyl and radicle, which depends on the amount of endosperm eaten by the weevils. However, the germination rate of acorns with hypocotyl and radicle was consistently high, irrespective of the degree of endosperm loss, which suggests that weevil-damaged acorns probably germinate, provided the hypocotyl and radicle survive until the cessation of damage. Research Fellow of the Japan Society for the Promotion of Science. This study was supported in part by Grants-in-Aid for Scientific Research from the Japan Ministry of Education, Science and Culture (No. 09001647, No. 10660144, and No. 11460068) and the Nippon Life Insurance Foundation.     

Preparation of novel reagents 4-alkoxytrityl chlorides and their reaction with methyl Α-d-glucoside

A series of novel 4-O-alkoxytrityl chlorides (1) with different chain lengths was synthesized as a novel reagent for obtaining 6-O-alkylated cellulose with high regioselectivity via trityl groups in one reaction step without the use of any protective groups. These chlorides were reacted with methyl -d-glucoside, which was used as a model compound, to examine the reactivities toward the primary hydroxyl groups of cellulose to afford a series of 6-O-alkylated methyl -d-glucosides in high yields. The product compounds were found to have interesting solubilities and thermal properties. Thus, newly prepared trityl chloride derivatives were found to be useful regioselective derivatization reagents on the primary hydroxyl group in carbohydrates, especially in cellulose.     

Surface deterioration of wood-flour polypropylene composites by weathering trials

The market for wood-fiber plastic composites (WPCs) is expanding rapidly in many countries including Japan, where WPCs are mainly used for exterior products. In such applications, WPCs undergo undesirable color change, chalking, and shrinkage and swelling, and accordingly there is a need to better understand the mechanisms responsible for the weathering of WPC and develop methods of improving their weathering resistance. In this study, weatherability of WPC was assessed by natural and accelerated weathering trials. Discoloration (whitening) of WPC during exposure was caused by degradation of both wood and plastic. Darker color pigments as additives improved the color stability of WPC; however, chalking on the surfaces still occurred. The color stability of WPC was improved by application of exterior coatings. Preweathering of WPC (before coatings were applied) increased the absorption of coatings by the WPC and had a positive effect on the color stability and prevented chalking of the composites. Parts of this study were presented at the IUFRO XXII World Congress Meeting, Brisbane, August 2005 and the IAWPS 2005, Yokohama, November 2005     

Tangential and radial shrinkage variation within trees in sugi (<Emphasis Type="Italic">Cryptomeria japonica</Emphasis>) cultivars

The transverse shrinkage variation within trees was examined for five sugi cultivars. The within-tree trends of tangential shrinkage (α _T) were different by cultivar, whereas radial shrinkage (α _R) increased from pith to bark in most cultivars. The tangential/radial shrinkage ratio (α _T/α _R) decreased from pith to bark in most cultivars, because the radial variation of α _R was larger than that of α _T. The cultivars showed significant differences among cultivars in α _T, α _R, and α _T/α _R, but the difference among cultivars for α _T/α _R was smaller. The relationships between transverse shrinkage and microfi bril angle (MFA), basic density (BD), tree ring parameters, and modulus of elasticity were examined. The α _T and α _R showed positive relationships with BD, latewood percentage, latewood density, and modulus of elasticity, and negative relationships with MFA and ring width. The relationships with earlywood density were weak. Sugi exhibited variation in transverse shrinkage within stem and among cultivars, with the variation affected by MFA, density, and tree ring parameters. Part of this article was presented at the 56th Annual Meeting of the Japan Wood Research Society, Akita, Japan, August 2006, and the 57th Annual Meeting of the Japan Wood Research Society, Hiroshima, Japan, August 2007     

Field trap test for bioassay of synthetic (1<Emphasis Type="Italic">S</Emphasis>,4<Emphasis Type="Italic">R</Emphasis>)-4-isopropyl-1-methyl-2-cyclohexen-1-ol as an aggregation pheromone of <Emphasis Type="Italic">Platypus quercivorus</Emphasis> (Coleoptera: Platipodidae)

An ambrosia beetle, Platypus quercivorus, is a vector of Japanese oak wilt, which causes massive mortality of oak trees in Japan. Previous studies have identified (1S,4R)-4-isopropyl-1-methyl-2-cyclohexen-1-ol ((−)-IMCH) as the major component of the aggregation pheromone of P. quercivorus. We tested the ability of synthetic (−)-IMCH to attract P. quercivorus adults. The synthetic compound attracted 14.4 times as many P. quercivorus, of both sexes, as control traps. Control and (−)-IMCH-baited traps both captured 3.32 times as many males as females, probably because of the nature of Lindgren funnel traps and of male-biased emergence sex ratio early in the season of adult flights. (−)-IMCH was proved to be a major component of the aggregation pheromone of P. quercivorus.     

Vertical soil–air CO2 dynamics at the Takayama deciduous broadleaved forest AsiaFlux site

At the Takayama deciduous broadleaved forest Asiaflux site in Japan, the ecosystem carbon dynamics have been studied for more than two decades. In 2005, we installed non-dispersive infrared CO₂ sensors in the soil below the site’s flux tower to systematically study vertical soil–air CO₂ dynamics and explain the behavior of soil surface CO₂ efflux. Soil–air CO₂ concentrations measured from June 2005 through May 2006 showed sinusoidal variation, with maxima in July and minima in winter, similar to the soil CO₂ effluxes measured simultaneously using open-flow chambers. Soil–air CO₂ concentrations increased with soil depth from 5 to 50 cm: from 2,000 to 8,000 ppm in the summer and from 2,000 to 3,000 ppm in the winter under snow. Summer soil–air CO₂ concentrations were positively correlated with soil moisture on daily and weekly scales, indicating that the Oi, Oe, and A horizons, where decomposition is accelerated by high-moisture conditions, contributed substantially to CO₂ emissions. This result is consistent with the short residence time (about 2 h) of CO₂ in the soil and larger emissions in shallow soil layers based on our diffusion model. We revealed for the first time that soil–air CO₂ concentrations in winter were correlated with both snow depth and wind speed. CO₂ transfer through the snow was hundreds of times the gas diffusion rates in the soil. Our estimate of the CO₂ efflux during the snow-cover season was larger than previous estimates at TKY, and confirmed the important contribution of the snow-cover season to the site’s carbon dynamics.     

Development of an air-injection press for preventing blowout of particleboard V: effects of board density and thickness on property of board manufactured from high-moisture particles

Particleboards with thickness of 10 mm and densities of 0.6, 0.7 and 0.8 g/cm³ were manufactured from high-moisture particles using urea–formaldehyde resin and the effectiveness of air injection was examined. The temperature in the 0.6 and 0.7 g/cm³ boards was lower with air injection than without during the initial to middle stages of pressing, while the temperature in the 0.8 g/cm³ board remained lower with air injection than without throughout the entire pressing process. Air injection reduced the pressing time required to manufacture the 0.6 and 0.7 g/cm³ boards and also increased the internal bond strength of boards of all densities. In the 0.6 and 0.7 g/cm³ boards, air injection reduced the modulus of rupture (MOR), while in the 0.8 g/cm³ boards, the MOR was similar between those manufactured by injecting and not injecting air. Air injection was also found to be effective for boards of high densities. The effectiveness of the air injection on thick boards was investigated by manufacturing 20-mm-thick boards of 0.7 g/cm³. Without air injection, it was not possible to manufacture the 20-mm-thick boards, even by extended hot pressing, but air injection allowed the boards to be manufactured by pressing for 16 min. Air injection was also shown to be effective for manufacturing thick boards.     

Performance of particleboard manufactured using air-injection press II: effects of board density and thickness on the performance of board manufactured from low-moisture particles

Particleboards of different densities (0.6, 0.7 and 0.8 g/cm³) and thicknesses (10 and 20 mm) were manufactured from low-moisture particles using an air-injection press. The effects of the air injection on preventing blowout of the boards of different densities and thicknesses were investigated by artificially creating blowout-prone conditions using metal frames. The effects of the air-injection pressure on the board performance were also investigated. 10-mm-thick boards of 0.8 g/cm³ pressed at 170 °C blew out when air was not injected, but were successfully manufactured by injecting air. 10-mm-thick boards at 150 °C showed constant internal bond (IB), regardless of density, but at 170 °C, IB was higher in boards of higher densities. This was likely due to accelerated hardening of the urea–formaldehyde resin at 170 than 150 °C. At both pressing temperatures, low air-injection pressure did not cause blowout and a reduction in board performance. Air injection also prevented the blowout of thick boards of 20 mm and enabled successful manufacture, showing its effectiveness. The IB of the 20-mm-thick board manufactured using the air-injection press exceeded that of 20-mm-thick board manufactured using an ordinary hot press.     

Automatic detection of washboarding in bandsaws

This paper presents an on-line method for detecting washboarding generated in bandsaws. It uses a parameter based on the shape of sawing force amplitude distributions. The curve of the probability density function of the parallel sawing force amplitude obeyed a normal distribution for the normal sawn surface, but it changed to an M-shaped distribution when washboarding appeared on the sawn surface of the workpiece. The curve of probability density function of the normal sawing force amplitude obeyed the normal distribution for any sawn surface investigated. The workpiece including a knot did not influence use of the parameter for detecting the appearance of washboarding.     

The effect of tractor logging on forest soil compaction and growth ofShorea selanica seedlings in Indonesia

The hardness in soil was investigated in four forest areas in Indonesia after a crawler tractor passed over it several times. The hardness in soil, expressed by bulk density, was measured at various depth and various distances from the main track. Recovery of soil hardness was also examined. The bulk density increased markedly by the first and second pass of the tractor, but did not change after the fifth pass. The bulk density was highest just under the main and the log track, and decreased with an increase in distance from the track (0.5 to 1.5 m). The greatest increase in bulk density was observed at the depth of 0–5 cm. The soil hardness tended to show recovery within 9 years after logging, though not completely. Growth and root penetration of seedlingsShorea selanica decreased with the increase of soil hardness. We considered that the 2 tractor passes that caused bulk density of 1.3 g/cm³ is critical for the growth ofS. selanica’s seedling.