Nitrogen use by <Emphasis Type="Italic">Pinus densiflora</Emphasis> trees growing on a Mt. Fuji lava flow

To quantify the nitrogen (N) use by Pinus densiflora trees growing on an infertile lava surface, N pools, N requirement and N uptake through fine roots and N deposition from the atmosphere were estimated. The N requirement and the N uptake of fine roots were 55.5kgNha^–1year^–1 and 39.7kgNha^–1, respectively. Thus, the ratio of N uptake to N requirement of the fine roots was 71.5%. Including fine-root contribution, the total N requirement of the P. densiflora trees was 98.6kgNha^–1year^–1, and the total N uptake was 64.2kgNha^–1year^–1. Thus, the N uptake of the P. densiflora trees was 64.1% of the N requirement, indicating that P. densiflora trees growing on an infertile lava surface obtain some of their N from below-ground organic material layers every year and the contribution of N storage in trees for their growth is not any higher than indicated in previous reports that excluded fine-roots contribution. The wet N deposition of our research forest was only 5.8% of the N requirement of the P. densiflora trees and only 8.9% of the N uptake. Movement of the below-ground organic material layer N concentrations in the F- and L-layers coincides with needle development and fine-root growth, suggesting the possibility that P. densiflora trees extract N from the organic N of those layers for growth.     

Mangrove forest productivity and biomass accumulation in Hinchinbrook Channel,Australia

Data on stand structure and rates of photosynthesis were used to estimate net canopy carbon fixation and carbon accumulation as living biomass in mangrove forests in Hinchinbrook Channel, Australia. Total annual canopy net carbon fixation was estimated to be about 29tCha–1yr–1. This equates to about 204,000tCyr–1 for all mangrove forests in Hinchinbrook Channel. Of this, only about 12% was stored as living plant biomass. Although it is not yet possible to present a robust carbon balance for mangrove trees, the remainder is presumably lost through plant respiration, litter fall, root turnover and exudation of organic compounds from roots.     

Mangrove structure,litter and macroalgal productivity in a northern‐most forest of Florida

Rhizophora mangle L. dominated 10 overwash islands within Tampa Bay forming the northernmost mangrove forests on the west coast of Florida. The mean number of trees and basal area were 5040 trees ha^-1 and 20.5m²ha^-1, respectively. Basal areas ranged from 1.1 (Avicennia germinans (L.) Stern), to 2.6m²ha^-1 (Laguncularia racemosa Gaertner), to 16.8 (R. mangle). Cockroach Bay mangroves are small (5.8–7.0m tall) versus coastal forests of south Florida and the Caribbean. Total litter production for a 12 month period was maximal in September for fringing (7.4gdwtm^-2d^-1) and interior (8.7gdwtm^-2d^-1) areas with the two zones not being significantly different. Average litter fall (3.1gdwtm^-2d^-1) was similar to more tropical Caribbean mangals. Leaves accounted for 68 of the litter and reproductive material for 6, being similar to tropical riverine and overwash marine angiosperm communities on the Mexican coast. Although mangrove forests in Tampa Bay are small in stature and experience cold damage and occasional frosts, their litter fall is similar in biomass to that of more tropical mangals. However, their reproductive output is low based on litter fall versus more tropical mangals suggesting that the northern extension is less than optimum. Macroalgal diversity was low (10 species) as compared to Caribbean mangals. Macroalgal turf (0.8gCm^-2d^-1) and epiphyte communities of A.germinans pneumatophores (2.7gCm^-2d^-1) have productivity levels that are equal to or greater than those of Caribbean mangals.     

Estimated stocks of organic carbon in mangrove roots and sediments in Hinchinbrook Channel,Australia

Aboveground and belowground root biomasses (Babove and Broot) were measured for young, isolated Rhizophorastylosa on Iriomote Island, Japan. The relationship between these two parameters was significant and given as the equation, Broot(g dry weight) = 0.394 × Babove(g dry weight) – 485 (r = 0.986). Multiple regression analyses also revealed good correlation between diameter and biomass of prop roots (Dprop and Bprop) and between prop root and root biomasses. Consequently, root biomass could be estimated from the measurements of diameter and biomass of prop roots using the multiple regression equation, Broot(g dry weight) = 80.0 ×Dprop(cm) + 0.86 ×Bprop (g dry weight) – 251. The relationship between DBH (diameter at breast height) and prop root biomass was also adequately described using an allometric equation.In Hinchinbrook Channel, Australia, redox potential (measured as Eh) and organic carbon stocks in the top 5cm of mangrove sediments were measured along a 600m transect from the frequently inundated, Rhizophora dominated zone on the creek edge, towards higher grounds, where Ceriops spp. became increasingly dominant. Eh values were about –60mV near the creek edge and increased to 260mV on higher grounds. Organic carbon stocks showed an opposite trend to Eh, with the values decreasing from about 360tCha–1 to 160tCha–1. At 18 sites, representing six different habitats, organic carbon stocks were also measured along with the DBH of mangrove trees. DBH was converted into aboveground biomass and then into root biomass using the equations obtained in the study on Iriomote Island. The average organic carbon stocks in the top 50 cm of sediments, aboveground biomass and root biomass were 296tCha–1, 123 tCha–1 and 52 tCha–1, respectively, and accounted for 64%, 25% and 11% of the total organic carbon stock.     

Interactions between the striped stem borer <Emphasis Type="Italic">Chilo suppressalis</Emphasis> (Walk.) (Lep., Pyralidae) larvae and rice plants in response to nitrogen fertilization

A screenhouse experiment was conducted to examine the damage and compensation in rice plants when injured by the striped stem borer, Chilo suppressalis (Walker), larvae at tillering stage, as well as larval survival and development of the insect at different nitrogen (N) fertilization levels. Potted plants were fertilized at late seedling stage at the rates 0, 200, 400, 600 and 800mgN/pot, respectively. More deadheads were caused as fertilization increased. Plants compensated well for injury at the fertilization concentrations of 200 and 400mgN/pot by producing new tillers, but such compensation did not take place at 600 and 800mgN/pot. Two weeks after infestation, the highest number of remaining healthy tillers was found in plants fertilized at 400mgN/pot. Larval survival varied little among the treatments 200 to 800mgN/pot. Larval weight attainment and/or developmental rate increased with increasing fertilization level from 200 to 600mgN/pot, but both declined rapidly as fertilization reached 800mgN/pot, indicating the great dependence of plant suitability on N fertilization levels. Conclusively, both the compensation response of rice plants and their suitability for C. suppressalis larvae could be significantly affected by N fertilization levels.     

Biological performance of wood-based composites treated with a formulation of 3-iodo-2-propynyl butylcarbamate and silafluofen using supercritical carbon dioxide

Wood-based composites (medium density fiberboard, hardwood plywood, softwood plywood, particleboard, and oriented strand board) treated with a mixture formulation of 3-iodo-2-propynyl butylcarbamate (IPBC) and silafluofen using supercritical carbon dioxide as a carrier solvent were evaluated for their resistance to biological attack in a laboratory study. The formulation was pre-pared by mixing 10g of IPBC and 1g of silafluofen in ethanol solution (20ml). Treatments were conducted at 35°C/7.85MPa, 35°C/9.81MPa, and 55°C/11.77MPa with the direct introduction of 20ml of the formulation into the treatment vessel with a capacity of ca. 2000ml at a rate of 2ml/min. Laboratory tests indicated that the treatment conditions used significantly enhanced the resistance of the treated wood-based composites against fungal and termite attacks. Because no significant difference in efficacy against both biodegrading agents was noticed regardless of the treatment conditions, the treatment at 35°C/7.85MPa was thought to be the most economical in terms of energy consumption and performance of treated materials. However, the amount of biocides in a formulation must be carefully selected in accordance with the required treatment condition to ensure satisfactory performance of the treated wood-based composites against any biological agent.     

Electromagnetic shielding efficiency of the electric field of charcoal from six wood species

Six wood species were carbonized under various carbonization temperatures and nonoxygen conditions to obtained charcoal. The effects of wood species, rate of temperature rise, and carbonization temperature on the electromagnetic shielding efficiency (ESE) of the electric field were investigated. The wood species used in this study were Japanese cedar, China fir, western hemlock, red oak, fortune paulownia, and Taiwan acacia. Tested materials were carbonized in a high-temperature oven under the following conditions: rate of temperature rise 1°–5°C/min; carbonization temperature 500°–1100°C, with temperature intervals of 100°C; maximum temperature maintained for 1h; and flow rate of nitrogen 300ml/min. The electromagnetic insulation strength system was used to detect the ESE of the electric field of charcoal. It was found that western hemlock and fortune paulownia charcoal showed maximum ESE values of of 36 and 61dB generated at a carbonization temperature of 1000°C. The charcoals derived from four other wood species showed maximum ESE values of 28dB for Japanese cedar, 23dB for China fir, 32dB for red oak, and 38dB for Taiwan acacia, respectively, at a carbonization temperature of 1100°C. The ESE value for fortune paulownia charcoal was similar to those of metal nets. The relations between ESE and logarithmic values of resistivity (log) could be represented by a negatively exponential formula.Part of this report was presented at the 50th Annual Meeting of the Japan Wood Research Society, Kyoto, April 2000     

Preservative treatment of wood-based composites with 3-iodo-2-propynyl butylcarbamate using supercritical carbon dioxide impregnation

Five structural-use wood-based composites [medium density fiberboard (MDF), hardwood plywood, softwood plywood, particleboard, oriented strand board (OSB)] were treated with 3-iodo-2-propynyl butylcarbamate (IPBC) using supercritical carbon dioxide (SC-CO₂) as a carrier solvent. Treatment was conducted at 35°C/7.85MPa (80kgf/cm²), 35°C/9.81MPa (100kgf/cm²), 35°C/11.77MPa (120kgf/cm²), 45°C/7.85MPa, 45°C/9.81MPa, 45°C/11.77MPa, 55°C/7.85MPa, 55°C/9.81MPa, and 55°C/11.77MPa. A decay test was carried out in the laboratory according to the modified Japanese standard method in which untreated and treated specimens were exposed for 12 weeks to a monoculture of the white-rot fungus Trametes versicolor (L.: Fr.) Pilat or the brown-rot fungus Fomitopsis palustris (Berk. et Curt.) Gilbn. and Ryv. IPBC/SC-CO₂ treatment protected the treated materials from decay by the two fungi, although the relative efficiency against decay varied with the treatment conditions and the type of wood-based composite. Better performance for MDF, hardwood plywood, and particleboard was generally obtained at high temperatures and pressures, whereas softwood plywood and OSB were most protected at low temperatures under any of the pressure levels tested.Part of this work was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002     

Changes in the physical and chemical properties of six Japanese softwoods caused by lengthy smoke-heating treatment

The effects of prolonged smoke-heating treatments on wood quality were investigated. Six Japanese softwoods were smoke-heated for 100 and 200h at a temperature of 75° ± 5°C, which was recorded inside the log. After smoke heating, wood quality, including moisture content, amounts of chemical components, relative degree of crystallinity (RDC) of cellulose, and sapwood color were examined. Moisture content decreased as a result of smoke heating, especially in sapwood, leading to a uniform distribution of moisture content within a log. Almost no difference was found in the amounts of chemical components between the control woods and the woods that were smoke-heated for 100h. However, in the wood that was smoke-heated for 200h, the amounts of holocellulose decreased, suggesting that thermal deterioration and/or degradation of hemicelluloses had occurred. We assume that the increase in RDC was caused by smoke heating with the crystallization of cellulose and/or thermal degradation of hemicelluloses. Almost no differences were found in sapwood color between the control woods and the woods that were smoke-heated for 100h. In the wood that was smoke-heated for 200h, however, L*decreased, whereas a* and b* increased. As a result, E*ab, showing the total color change, increased, resulting in a deeper color. These results suggest that thermal degradation of hemicelluloses was caused by smoke heating for over 100h. Therefore, smoke heating of softwood logs using a commercial-scale kiln should not exceed 100h.     

Physiological and psychological responses to prolonged light floor-impact sounds generated by a tapping machine in a wooden house

We investigated the physiological and psychological responses of nine normal men to the prolonged light floor-impact sounds of 60dBA and 80dBA generated by a tapping machine in a two-story wooden house. Blood pressure was measured, and a sensory evaluation was also conducted using the semantic differential method. The results obtained were as follows: (1) the increase in systolic blood pressure immediately after exposure to the light floor-impact sounds depended on the level of the sounds, (2) the variations in feelings due to the prolonged light floor-impact sounds were identified by factor analysis, and (3) the subjects showed no difference in comfortable feeling for the prolonged light floor-impact sounds of 60dBA and 80dBA, but differences in the variation of the systolic blood pressure were detected.Part of this research was presented at the 47th Annual Meeting of the Japan Wood Research Society, Kochi, April 1997     

Characteristic Raman bands for <Emphasis Type="Italic">Artocarpus heterophyllus</Emphasis> heartwood

The Raman spectrum of Artocarpus heterophyllus heartwood, which proved to be a rich source of flavonoids, exhibited two characteristic bands, at 1247cm^–1 and 745cm^–1. The bands also appeared in the Raman spectrum of the yellow-brown needles extracted from the heartwood with methanol. Based on the Raman measurements of flavones and related compounds, it was predicted that the Raman band at 1247cm^–1 may be attributed to flavonoid-type compounds. No vibrational band corresponding to the characteristic Raman bands was observed by diffuse reflectance infrared spectroscopy. Thus, it was suggested that observation of the characteristic bands is an advantage of Fourier transform-Raman spectroscopy for nondestructive analysis of wood.     

Lateral fluxes of organic carbon in a mangrove forest partly contaminated with sewage wastes

Lateral fluxes of macrodetritus, particulate matter and dissolved organic carbon were determined. Samples were collected monthly at the mangrove forest–inshore water boundary and within the forest. Floating macrodetritus (mainly mangrove leaves) was collected by a net (2mm mesh size). Dissolved and particulate matter were separated by filtration (0.45m filter) and centrifugation. Dissolved and particulate carbon were determined by a total organic carbon analyser (SHIMADZU model TOC5000). There was a significant export of mangrove litter to the adjacent marine environment during spring tides. Rates of import and export of particulate matter in the forest were not statistically different. Translocation of material within the forest was clearly demonstrated. A relatively high export of macrodetritus was recorded at the marine fringe (mainly colonised by Sonneratia alba). There was low export of litter in the terrestrial fringe zone, a monospecific stand occupied by Avicennia marina (Forsk) Vierh. Net organic carbon export from the entire forest was 79×10⁶g C y^–1, dissolved organic carbon accounted for about 78% of the total export.     

Effects of a nursery CO2 enriched atmosphere on the germination and seedling morphology of two Mediterranean oaks with contrasting leaf habit

The use of an enriched CO₂ atmosphere in tree nurseries has been envisaged as a promising technique to increase productivity and to obtain seedlings with a higher root/shoot ratio, an essential trait to respond to water stress in Mediterranean-type ecosystems. In that framework, we have analyzed the effects of three levels of atmospheric CO₂ concentration (350, 500 and 700ppm) on the germination rate, growth and morphology of seedlings of two Mediterranean oaks used in reforestation programs: the evergreen Quercus ilex L. and the deciduous Quercus cerrioides Wilk. et Costa. CO₂ enrichment increased the germination rate of Q. cerrioides (from 70±7 to 81±3%) while it decreased that of Q. ilex (from 71±10 to 41±12%). Seedlings of both species increased approximately 60% their total biomass in response to CO₂ enrichment but at two different CO₂ concentrations: 500ppm for Q. cerrioides and 700ppm for Q. ilex. This increase in seedlings biomass was entirely due to an augmentation of root biomass. Considering germination and biomass partitioning, an enriched CO₂ atmosphere might not be appropriate for growing Mediterranean evergreen oaks, such as Q. ilex, since it reduces acorn germination and the only gains in root biomass occur at a high concentration (700ppm). On the other hand, a moderate CO₂ enrichment (500ppm) appears as a promising nursery technique to stimulate the germination, growth and root/shoot ratio of deciduous oaks, such as Q. cerrioides.     

Effects of nitrogen and phosphorus fertilization on the growth and nutrition of hybrid poplars on Vancouver Island

The effects of nitrogen (N) and phosphorus (P) rates, P source, and method of P application were tested on growth and nutrition of four clones of hybrid poplar (Populus trichocarpa Torr. & Gray×P. deltoides Bartr. ex Marsh or P. trichocarpa×P. maximowiczii A. Henry) in a plantation on Vancouver Island. Treatments were applied shortly after planting. Nitrogen (0, 500kgNha^–1) was supplied as ammonium sulfate (AS); half of the AS was added at the start of the second growing season. Phosphorus (0, 100, 200kgPha^–1) was supplied as triple super phosphate (TSP), rock phosphate (RP), or diammonium phosphate (DAP) and banded or broadcast. Over four growing seasons, stem volumes increased with AS and P additions. The effects of AS and P each were greatest when the other was also added. Volume was greater when P was applied at 100kgha^–1 than in the P control and did not significantly increase further at 200kgPha^–1. Phosphorus additions were more effective when added as TSP or DAP than when added as RP, but only in P100 and when banded. Banding increased volume when P was applied at 200kgha^–1, but increases were significant only for DAP fertilized trees. Roto-tilling associated with the banding treatment also increased volume when AS and P were not added. Rankings of clones with respect to stem volume varied with N supply and changed over time.     

Concentration and molecular weight distribution of dissolved organic carbon in a mangrove creek in the Hinchinbrook area,Australia

The concentration and molecular weight distribution of dissolved organic carbon (DOC) are reported for a mangrove creek in the Hinchinbrook area, Australia. DOC concentration ranged from 1.0mg Cl–1 near the creek mouth to 2.2mg Cl–1 at the innermost part of the creek. There was no apparent spatial trend in molecular weight distribution of DOC, with a >300gmol–1 fraction accounting for about 70% of the total in all samples. DOC concentration fluctuated between 0.5 and 1.2mg Cl–1 over one tidal cycle. The samples collected at low tide and during the rising tide were dominated by DOC of >300gmol–1 and <300gmol–1, respectively. This suggested the export of high molecular weight DOC, probably originating from litter leachates, and the import of low molecular weight DOC to the creek.     

Studies on hypersaline-tolerant white-rot fungi IV: effects of Mn 2+ and NH 4 + on manganese peroxidase production and Poly R-478 decolorization by the marine isolate Phlebia sp. MG-60 under saline conditions

Manganese peroxidase (MnP) production by Phlebia sp. MG-60 is strongly regulated by Mn²⁺ and NH₄⁺ at various sea salt incubation conditions. Extra-added Mn²⁺ and NH₄⁺ obviously inhibited MnP production, but sea salts relieved the inhibition partially or completely. Three media were prepared: Kirk medium with addition of 0%–5% sea salts (KS medium), a high level of Mn²⁺ (300mg/l) in KS medium (HM-KS medium), and a high level of NH₄⁺ (430mg/l) in KS medium (HN-KS medium). Without addition of sea salts, the dye Poly R-478 was significantly decolorized by low MnP activity (about 200U/l) and a low level of laccase activity (about 100U/l) in KS and HM-KS media. In the cultures in which laccase activity was almost completely inhibited by 3% and 5% sea salts, MnP activity higher than 400U/l was necessary for Poly R-478 decolorization in all of the three media. We first report the linear correlation of MnP activity and decolorization of Poly R-478 under saline conditions and the effect of laccase on this relation.     

Soil respiration and soil CO<Subscript>2</Subscript> concentration in a tropical forest,Thailand

Soil respiration and soil carbon dioxide (CO₂) concentration were investigated in a tropical monsoon forest in northern Thailand, from 1998 to 2000. Soil respiration was relatively high during the rainy season and low during the dry season, although interannual fluctuations were large. Soil moisture was widely different between the dry and wet seasons, while soil temperature changed little throughout the year. As a result, the rate of soil respiration is determined predominantly by soil moisture, not by soil temperature. The roughly estimated annual soil respiration rate was 2560gCm^–2year^–1. The soil CO₂ concentration also increased in the rainy season and decreased in the dry season, and showed clearer seasonality than soil respiration did.     

Dependence of reaction kinetics and physical and mechanical properties on the reaction systems of acetylation II: physical and mechanical properties

Acetylation of wood was carried out in acetic anhydride only, acetic anhydride/xylene 1:1 (v/v), and acetic anhydride/pyridine 4:1 (v/v) solutions. The antishrink efficiency (ASE), hygroscopic properties, vibrational properties, and bending strength were compared among the three reaction solutions. The ASE was a simple function of weight gain (WG); the equilibrium moisture content at a given WG differed among the reaction solutions. Based on this fact and the results of repeated water soaking and oven-drying tests, it was found that the bulking effect was a major factor, and that decreased hygroscopicity contributes only slightly to the dimensional stabilization by acetylation. The difference in equilibrium moisture content among reaction solutions appears more significant in block samples than wood meal, probably due to the fiber-to-fiber bonds in the former. The tendencies for change in the specific Youngs modulus and the loss tangent differed among reaction solutions, whereas in the static bending test the difference was not marked.Part of this report was represented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002     

In vitro propagation of <Emphasis Type="Italic">Oroxylum indicum</Emphasis> Vent. a medicinally important forest tree

In vitro propagation of Oroxylum indicum Vent. was carried out using cotyledonary node explants. Among the different types of cytokinins used for culture establishment, 6-benzyladenine exhibited the best response with higher concentrations (8.87µM or above) for inducing multiple shoots. Inclusion of indole-3-acetic acid (2.85µM) into 6-benzyladenine-supplemented medium triggered a high frequency of response as well as a proliferation of shoots. The best medium for proliferation was Murashige-Skoog (MS) medium with 6-benzyladenine (8.87µM) and indole-3-acetic acid (2.85µM). However, incorporation of gibberellic acid (1.44µM) was mandatory to enhance shoot elongation. Repeated subculturing of cotyledonary node and in vitro developed nodal segments in MS medium with 6-benzyladenine (4.44µM) at 4-week intervals resulted in continuous mass multiplication of shoots without any evidence of decline. Root induction was best (91.6%) when MS strength was reduced to one-quarter and combined with -naphthalene acetic acid (2.69µM) and indole-3-acetic acid (5.71µM), with a high survival rate (70–72%) of plantlets hardened in either soil rite or soil:sand:soil rite (1:1:2).     

Effect of auxins (IBA and NAA) and season on rooting of juvenile and mature hardwood cuttings of Robinia pseudoacacia and Grewia optiva

Juvenile (2 year old trees) and mature hardwood (15 year old trees) cuttings of Robinia pseudoacacia and Grewia optiva were tested for their capacity to form roots. Cuttings were prepared in spring, monsoon and winter seasons and treated with different concentrations (250, 500 and 750 mg/l) of IBA and NAA. These were planted in a mist chamber maintained at 25±1°C with relative humidity >70%. Juvenile cuttings of both species rooted significantly better than mature hardwood cuttings in all three seasons, and the age effect was more pronounced in auxin treated cuttings. The highest rooting in juvenile (83.3%) and mature (66.6%) cuttings was observed with the NAA (500 mg/l) treatment in R. pseudoacacia during the spring season. In G. optiva, IBA (250 mg/l) in the monsoon season was most effective and yielding a maximum of 80% and 70% rooting in juvenile and mature cuttings, respectively. Auxin treatments also significantly enhanced the number of roots, root length, leaf number and leaf area. Statistical analysis of data revealed that interactions between age, season and treatments were significant at P <0.05 level for R. pseudoacacia and non-significant for G. optiva.