Soil physical properties and preferential flow pathways in tropical rain forest, Bukit Tarek, Peninsular Malaysia

Soil physical properties and water movement within soil were investigated using dyes in a tropical rain forest, the Bukit Tarek Experimental Watershed of Peninsular Malaysia. The saturated hydraulic conductivity (K _s) decreased with increasing soil depth. TheK _s values were higher than those reported for other tropical soils. The geometric means of theK _s values ranged from 4.69×10⁻³ (80 cm) to 4.07×10⁻² cm s⁻¹ (10cm). This suggests saturation overland flow may not be dominant but that subsurface flow must play an important role in stormflow generation. The shapes of the soil moisture characteristic curves resembled those of forest soils which have large changes in volumetric water content at pressure heads <30 cmH₂O. The relatively high conductivities were due to the presence of a porous zone of decomposed root channels which existed continuously in vertical direction. Besides decayed roots, living roots also encourage preferential flow in vertical and lateral (downslope) directions. Termite activities may also form water flow pathways in tropical regions. These detailed results help us analyze water flow within the soil in tropical rain forests.     

Working time design for industrial forest plantations in East Kalimantan

The objectives of this study were to clarify physiological loads under tropical conditions and to establish a proper working time design for tropical forestry operations. The research was conducted in East Kalimantan, Indonesia, in 1995. In this research, physiological loads and thermal conditions were investigated under various conditions,i.e., in forests and nurseries, on roads and at logged-over areas. Using the standards of the American Conference of Governmental Industrial Hygienists (ACGIH), a structure of work to rest proportions could be designed properly. Results showed that felling and cutting trees and weeding in the forest could be done continuously early in the morning and with 25% rest time for the remainder of the work day. Spreading fertilizer at the nursery could be done almost continuously all day. Road maintenance could be performed continuously during early morning but 50–100% rest time was needed for the remainder of the day. At logged-over areas, path clearing using chainsaws and soil hoeing required 50% rest early in the morning and 75–100% rest after that time, while planting required 25% rest early in the morning and 50–100% rest after that time. In conclusion, work done at logged-over areas required a greater percentage of rest time than work at other locations except early in the morning. A part of this paper was orally presented at the 107th Annual Meeting of the Japanese Forestry Society (1996). Corresponding author.     

Lignans ofLinum flavum var.compactum

A new dibenzylbutyrolactone lignan 7.6-dihydroxybursehernin, together with six known lignans (pinoresinol, lariciresinol, secoisolariciresinol,-peltatin,-peltatin, 5-methoxypodophyllotoxin) were isolated from the methanol extracts ofLinum flavum var.compactum. The enantiomeric analysis of pinoresinol and lariciresinol isolated from the species, which are upstream lignans in the lignan biosynthetic pathway, indicated that they are not optically pure, which is in accordance with our recent findings on lignans occurring in other plant species.Parts of this report were presented at the 42nd Lignin Symposium, Sapporo, October 1997; and the 43rd Lignin Symposium, Fuchu, October 1998     

Forest soil and litter as filtering media for suspended sediment

A series of two filtration experiments were conducted to evaluate the filtration function of forest soil experimentally. The first experiment evaluated the differences between the filtration capabilities of the A₀ horizon and A horizon, and the effect of overstory species on the filtration function of the A₀ horizon. Undisturbed A₀, A and A₀+A horizons were collected for the filter mediums with cylindrical samplers. Leaves ofQuercus serrata, Quercus myrsinaeforia, Sasa senanensis Pinus densiflora, Chamaecyparis obtusa, andCryptomeria japonica were also packed in the samplers. Various suspended sediment concentration of water were sprayed at constant intensity on the surface of samples. Filtering coefficients were not affected by SS concentration in all samples, and the order of filtering coefficient was: A₀ horizons>A₀+A horizons>A horizons in undisturbed forest soil samples, andQuercus serrata>Sasa senanensis>Quercus myrsinaeforia>Pinus densiflora”Chamaecyparis obtusa>Cryptomeria, japonica in leaf samples. These results led to the conclusion that SS from managed forests can best be prevented by buffer zones where a thick A₀ horizon is maintained. The second experiment evaluated the effect of turbid water supply rate on the filtration capacity. Undisturbed A horizons and four leaf types,Quercus serrata, Pinus densiflora, Chamaecyparis obtusa, andCryptomeria japonica were used as filter mediums. Filtering coefficients were inversely proportional to supply rate of turbid water in all samples.     

Application of Universal Soil Loss Equation (USLE) to mountainous forests in Japan

Universal Soil Loss Equation (USLE), originally developed by the USDA for agricultural lands and then used throughout the world, was applied in mountainous forest terrain in Japan. The slope length and steepness factors were extended for long slope lengths and steep slopes by recalculating the data from available literature in Japan and by using data from supplementary erosion experiments. As such, we conclude that the USLE can be used successfully to estimate surface erosion on long, steep mountainous forest slopes. The cover and management factors of many kinds of natural and artificial forest stands, cutting types, and disturbance regimes were calculated from the literature. The support practice factors of many types of soil and water conservation practices were also calculated from published information. Based on these results, we showed that the USLE can be applied to estimations of soil erosion from wide areas including many kinds of agricultural and forest lands. This study was funded by the Agricultural, Forestry, and Fishery Technology Council Office for comprehensive studies on agriculture, forestry, and fisheries and the agricultural, forestry, and fishery trading, resources, and environments.     

A vaccine prepared from a non-pathogenic H5N1 influenza virus strain from the influenza virus library conferred protective immunity to chickens against the challenge with antigenically drifted highly pathogenic avian influenza virus

Inactivated influenza virus vaccine prepared from a non-pathogenic influenza virus strain A/duck/Hokkaido/Vac-1/2004 (H5N1) from the virus library conferred protective immunity to chickens against the challenge of antigenically drifted highly pathogenic avian influenza virus (HPAIV), A/whooper swan/Hokkaido/1/2008 (H5N1). The efficacy of the vaccine was comparable to that prepared from genetically modified HPAIV strain deltaRRRRK rg-A/ whooper swan/Mongolia/3/2005 (H5N1), which is more antigenically related to the challenge virus strain, in chickens.     

The biological activities of cardenolide triglycosides from stems, twigs, and leaves of Nerium oleander

Sixteen cardenolide triglycosides (1?C16) were isolated from stems, twigs, and leaves of Nerium oleander. Among them, 3??-O-(4-O-gentiobiosyl-d-diginosyl)-7??,8-epoxy-14-hydroxy-5??,14??-card-20(22)-enolide, named cardenolide B-3 (16), was isolated from natural sources for the first time. The in vitro anti-inflammatory activities of compounds 1?C16 were examined on the basis of inhibitory activity against the induction of intercellular adhesion molecule-1 (ICAM-1). Compounds 1?C5 were active at an IC50 value of less than 7 ??M. The cytotoxic activity of isolated compounds was evaluated against three human cell lines: normal human fibroblast cells (W-38), malignant tumor cells induced from WI-38 (VA-13), and human liver tumor cells (HepG2). Compounds 1?C5 were active toward WI-38 cells; compounds 1, 3, and 5 were active toward VA-13 cells; and compounds 1?C5 were active toward HepG2 cells at IC₅₀ values of less than 10 ??M. The multidrug-resistant (MDR) cancer-reversal activity of compounds 1?C16 was evaluated on the basis of the amount of calcein accumulated in MDR human ovarian cancer 2780AD cells in the presence of each compound. Compounds 13 and 14 showed significant effects on calcein accumulation.