We measured the concentrations of dissolved iron (Fe_d) and aluminum (Al_d) in stream water in two forested catchments in Kyoto Prefecture. The average Fe_d concentration ranged from 0.39 to 1.25μmol 1^<-1> and that of Al_d from 0.38 to 1.14μmol 1^<-1>. Fe_d concentration increased in summer and decreased in winter. A similar seasonal pattern was observed for dissolved organic carbon(DOC). Fed_ and Al_d concentrations correlated significantly with DOC concentration, suggesting that Fe_d and Al_d in stream water are complexed with organic matter. In addition, the Al_d apparently had little bad influence on organisms in the stream because it was present in low concentrations and because it was part of an organic complex.

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For conservation of water quality of the Shimanto River basin, I estimated the discharged load of total N in the Shimanto River basin based on the pollutant load factor using GIS which was 4.9 ton/day in 1995. The discharged load of forest included by the diffuse load was 2.1 ton/day and the proportion of forest load in total was 43%. The proportions of discharged load from 4 load sources were as follows: residential(14%), industrial(2%), stock-breeding(27%), and diffuse source(57%). The discharged load of total N was 2.3 times higher than the forest load, which is the base load when there is no human activity. I also estimated the discharged load of total N in the Yusuhara River basin, the Hiromi River basin, the Iezigawa Dam catchment, and the Gudo catchment, which are all part of the Shimanto River basin. The 4 load sources had different effects at each of these 4 locations. Forest discharged load in the Yusuhara River basin was largest, while discharged load from human activity was largest at the other basins. Total N in discharged load (4.0 ton/day) was comparable to total N in run-off load (4.7 ton/day) at Gudo. A comparison of flow rate and run-off load showed that the swelling had a greater effect on run-off load.

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Decomposition of oak leaf litter in a Quercus serrate forest was studied for 12 months using litter boxes. The box was made from PVC(Polyvinyl chloride) cylinder(φ: 10cm, height: 9.0cm) and its both ends were covered with different mesh sizes (1.0mm and 25μm). The litter boxes with 25μm mesh size were used to exclude mesofauna and the boxes with 1.0mm mesh size were used to allow the access of microbiota and mesofauna. The environmental conditions (temperature, relative humidity and litter moisture content) in the boxes did not differ between the two treatments. The 25μm mesh treatment was very effective in excluding mesofauna. The weight loss of leaf litter was significantly higher in the 25μm boxes than that in the 1.0mm boxes at 3 months, but the differences in the two treatments were not significant at 6, 9 and 12 months. The annual decomposition constants (k) were 0.57 and 0.53yr^<-1> in the 1.0mm and 25μm boxes, respectively. The amounts of nitrogen remaining were not significantly different between the two treatments throughout the study period. The C/N ratio was significantly lower in the 1.0mm boxes than in the 25μm boxes at 12 months. Our results indicate that the mesofauna had a negative effect on the litter weight loss in the nitrogen immobilization phase (0-3 months), but their contribution to the rates of weight loss and nitrogen mineralization of Q. serrate leaf litter was negligible over a one-year period.

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Leaf area index(LAI) of undergrowth larger than 0.3m in stem length was estimated in a natural forest at southwest Kochi, Japan. The forest is characterized by Hinoki cypress (Chamaecyparis obtusa) and Tsuga hemlock (Tsuga sieboldii) mixed with evergreen Quercus spp. and other broadleaved spp. We settled twenty-two small plots along the forested ridge and on slope and a transect across a canopy gap opened by selective logging of Hinoki trees. Size structures were examined for saplings (less than 5cm in DBH and larger than 0.3m in stem length) mostly shared by evergreen broadleaved species. Sample saplings were harvested and measured their stem, branch and leaf weight, and leaf area, to determine their allometric relationships among size parameters. Averaged undergrowth biomass estimated for non-foliage and foliage were 2.00 and 0.62 ton/ha at forested sites, and 5.94 and 2.39 ton/ha at gap site, respectively. LAI estimates for forested sites ranged from 0.08 to 2.18 m^2/m^2 with 0.78 m^2/m^2 as the average, and 0.31 to 7.87 m^2/m^2 for gap with 2.90 m^2/m^2 as the average. Foliage biomass of undergrowth in this stand is large enough as corresponding to about one-fourth in leaf biomass and about 10% in LAI of reviewed values of Japanese evergreen broadleaved forests, hence it is not at the negligibly small level.

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Tree height and basal diameters of 10 years old Hinoki (Chamaecyparis obtusa) seedling families obtained from 6-clone diallel crosses were measured to study their combining ability. General combining ability was recognized in the growth of their height and basal diameter and there were differences of the general combining ability in reciprocal crossing. Specific combining ability was seen in the growth of their basal diameter. The reasons why the differences of their general combining ability in reciprocal crossing recognized are that there exists a specific clone whose growth is low when they were used as female parents and high as male parents, and that the growth of basal diameter was differentiated by their female parents rather than their male parents. These results imply that not only general combining ability but also differences of their general combining ability in reciprocal crossing and specific combining ability should be taken into consideration when breeding for growth is conducted.

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Insects attacking acorns of 4 deciduous oaks, Quercus serrata, Q. aliena, Q. acutissima, and Q. variabilis, at the same site were investigated. Seasonal changes in acorns dispersed, insect fauna on pre-dispersal acorns, and the damage rate by each insect on pre-dispersal acorns differed between Section Prinus (Q. serrata and Q. aliena) and Section Cerris (Q. acutissima and Q. variabilis), but were similar between species in the same section. Total number of acorns of Section Prinus was larger than that of Section Cerris, but the biomass of acorns was not different between sections. Trees of Section Prinus dispersed a lot of acorns with discolored cotyledons (most of them might have been aborted acorns) and immature acorns absorbed by weevils. In particular, Q. serrata dispersed the largest number of absorbed acorns among 4 tree species, and as Q. variabilis dispersed the smallest number. Thus, Q. serrata, which dispersed the largest number of acorns among 4 oak species, dispersed the smallest biomass of uninjured acorns, but Q. variabilis, which dispersed the smallest number, dispersed the largest biomass without injury. Insect damage to post-dispersal acorns was similar for all oak species.

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The number of beetles landing was assessed for logs of Quercus serrata bored by male Platypus quercivorus with different densities in field. The number of both male and female beetles collected by adhesive traps set over logs correlated to the number of entry holes bored by the males until the 11th day of the investigation, but it tended to be density-independent at large number of entry holes. This result suggested that the effect of attractiveness of male's entry hole was limited against its number. After the 11th day, the number of collected beetles was greatly reduced, and did not correlate to the number of entry holes. Only one entry hole was bored by a landed male additionally among all logs investigated in the study period. A few holes had the main gallery bored after mating, and no beetles lived in all holes of all logs, which were cut open on the 28th day. These results suggest that when only a few males bore into a tree or a log which has been attacked en masse and on which a large numbers of males and females are landing, the number of males and females landing will decrease quickly and the attack will end, because all single males in holes will have mated, died, or left the holes and the attractiveness declines.

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Numbers of entry holes and of beetles emerged from logs of Quercus crispula that had been bored and killed by Platypus quercivorus, were investigated according to height above the ground. The number of entry holes tended to increase as the height above the ground decreased, but some were found higher than 10m above the ground. The number of beetles emerged per volume of sapwood or per entry hole tended to increase with height above the ground. Therefore, on some trees the number of beetles emerged lower than 2m high above the ground was less than 30 percent of the total number of beetles emerged from the trees. Although the width of the stem tended to decrease as the height above the ground increased, there was no difference between the width of sapwood where beetles propagate in the lower part of the tree and the upper part of the tree. Therefore, it was suggested that the low density of entry holes in the upper part of the tree decreased intraspecific competition for habitat space and increased the number of beetles emerged per entry hole.

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Biomass (B, ton/ha) and vegetation coverage (V, %) of understories were studied in old Chamaecyparis obtusa plantations (70-95 years) at the northern part of Okayama Prefecture. The relationship between stand density (SD, trees/ha) and relative light intensity (RLI, %) was expressed by power equation (RLI=6320 SD^<1.10>, R^2=0.679, P<0.01). B and V were expressed as a function of RLI, B=0.288 RLI^<1.24>, r^2=0.460, P<0.05 and V=3.57 RLI+27.29, r^2=0.365, P<0.05, respectively. B and V were significantly correlated with mean DBH(r^2=0.600, 0.514, P<0.01). We concluded that B and V could be estimated by one of the stand parameters such as stand density,RLI and DBH.

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Mass loss and nitrogen dynamics of decaying boles were evaluated in a Hinoki cypress plantation in Higashitsuno Village, Kochi Prefecture. Samples of boles with a diameter of 5 to 10cm thinned in 1994, 1998 and 2002 were collected and density and nitrogen contents in the samples were measured. The density of boles decaying for 0, 4 and 8 years was 436, 354, and 211kg/m^3 respectively. The decomposition constant determined from the exponential regression model was 0.091/yr and half time of disappearance was 7.6 years. Nitrogen content of boles decaying for 0, 4 and 8 years was 445, 434, and 423gN/m^3, and did not change significantly during the decomposition. We concluded that at the study site, nitrogen immobilization from the outer environment was insignificant, and microbes efficiently utilized the nitrogen inside the boles.

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We inoculated three strains of the hyphae of Shiitake mushroom, Lentinula edodes to stems and logs of Quercus crispula trees killed by the infestation of an ambrosia beetle, Platypus quercivorus in order to investigate the effect of L. edodes to prevent emergence of the beetle. The number of beetles emerged from logs was not significantly different between strains and between logs with L. edodes and logs with holes as well as logs with L. edodes. The number of beetles emerged from standing trees was largest at trees without holes, but it did not differed from both trees with L. edodes and trees with holes. The number from standing trees was smallest at trees with the strong strain to obstruct the spawn expansion of the oak-infectious fungus, Raffaelea quercivora. However, it did not significantly differed between strains and between trees with L. edodes and trees with holes. As these results, although L. edodes may affect to prevent emergence of the beetles, drying through holes bored artificially may have high effect to prevent it.

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Effect of malt extract(ME) addition on decomposition of lignin and carbohydrate was examined in oak wood (Quercus serrata) inoculated with four fungal isolates (Lentinula edodes, Trametes versicolor, Daedalea dickinsii, Laetioporus sulphureus) under a laboratory condition. ME addition enhanced mass loss of wood by T. versicolor and had minor effects on mass loss of wood by L. edodes, D. dickinsii and L. sulphureus during 24 weeks of decomposition. ME addition enhanced lignin decomposition by T. versicolor, L. edodes and D. dickinsii and enhanced carbohydrate decomposition by T. versicolor, indicating ME was used as a source of energy and nutrients for oak wood decomposition by these fungi. ME addition had minor effects on selective carbohydrate decomposition by L. sulphureus, suggesting the effects of ME was different depending on fungal species.

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