We investigated influences of mast seeding on tree growth, in relation to beech tree species Fagus crenata and F. japonica dynamics of leaf litterfall. The study objective was to clarify any relations between mast seeding and twelve years of leaf litterfall and basal area increment of mature F. crenata and F. japonica trees in a natural forest. Results showed both Fagus species decreased in leaf litterfall mass (g/m²) with increasing amount of nuts and cupules. This suggests that leaf production was smaller in good or middle seed mast years compared to poorer or non-seed years. Results further showed a decline of basal area increment during good seed years. Moreover, decline of basal area increment seemed to extend into the year after good seed years. This suggests that the ontogeny for both F. crenata and F. japonica might require several years to restore resources for reproductive organs for flowering and mast seeding.

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For improving the wood properties of Sakhalin fir (Abies sachalinensis) variation in annual ring structure and genetic variation in different environments were examined by X-ray densitometry. The specimens were sampled from 32- to 41-year-old open-pollinated families in progeny test stands, which were 74 families totaling 444 trees in Bibai and 24 families totaling 96 trees in Akkeshi. Six components were analyzed as growth ring components-ring width (RW), earlywood width (EW), latewood width (LW), ring density (RD), earlywood density (ED), and latewood density (LD). The values of LW and LD in Akkeshi were smaller than those in Bibai under the influence of low temperature and short sunlight hours in summer. Narrow sense heritability of ring components was 0.17∼0.27 for width and 0.26∼0.34 for density in Bibai and 0.47∼0.79 for width and 0.26∼0.66 for density in Akkeshi. The value of heritability of LW and LD in Akkeshi was different for other traits, probably because of the summer weather. The analysis using 23 common families in two stands indicated that interaction between families within provenance and stands was significant in LW, RD, ED, and LD. Therefore, seed zones are as necessary for wood density as resistance to weather damages and disease, or growth.

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We aimed to clarify 1) whether the roots of current-year seedlings of riparian component species have developed acclimation to soil substrate particularly in the riparian zone, and 2) if the acclimation affects the seedling survival rate. To address these questions, we investigated root morphology of Pterocarya rhoifolia seedlings and the survival rate in different edaphic habitats (sandy soil and rock substrate) in the riparian zone located in a deciduous broadleaved forest in the cool-temperate region, comparing them with those of Carpinus laxiflora and C. tschonoskii established in the same site. The longest length of lateral root, the longest root length (the longest distance from the base of root to root apex) and ratio of the longest length of lateral-root to the tap-root length of P. rhoifolia seedlings in the rock substrate were higher than those in the other species or in the other site. This indicated that P. rhoifolia seedlings have a higher ability to develop the lateral root acclimating to rock substrate than the other species. The survival rate of P. rhoifolia seedlings also was higher in the rock substrate, suggesting that the acclimation of root morphology to rock substrate encourages their establishment and the survival of this species in the riparian zone.

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Rhizome expansion system of bamboo (Phyllostachys pubescens) was investigated in a northwest part of Gifu Prefecture. Growth pattern was observed by measuring annual rhizome elongation in 10 m×10 m studied area. This was done by removing the soil in the studied area using shovel and water under pressure. Our results revealed that 1) internode length of bamboo rhizome has yearly amplitude in increase. Short parts of internodes that we assumed border of age were 7 to 29 mm, which was less than 40% of the longest internodes in all amplitudes, respectively. 2) Annual rhizome elongations were 0.02 m to 3.67 m, keeping an average of 1.27 m±0.90 m in 50 rhizome branches. These values are smaller than the previously reported research on rhizome elongation in west Japan. 3) Rhizome elongation and branch numbers had a periodic annual increase with an interval of 3 years. 4) By observing annual growth pattern it was also predicted that the process time of rhizome expansion in the studied area were developed within 4 to 12 years duration. Finally it can be concluded that the total annual elongation of bamboo rhizome can be estimated from the length combination of bamboo internodes, but we need more study to clarify the effects of soil and climate conditions on the growth of rhizomes.

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Forest-floor vegetation and regeneration of tree species were investigated inside and outside a deer-proof fence that had been constructed 7 years earlier in a cool temperate deciduous forest in the Tanzawa Mountains, where dwarf bamboo (Sasamorpha borealis) had been browsed and diminished by sika deer. This study examined the effect of the deer-proof fence on tree species regeneration. The vegetation cover on the forest floor, cover and culm height of dwarf bamboo, and density and height of seedlings and saplings were higher inside the fence than outside the fence. Species composition consisted of dwarf bamboo, trees, and shrubs inside the fence, whereas annual herbs and short perennial herbs were found outside the fence. The density of regenerated trees was higher inside the fence than outside the fence, and the difference was more than 6-fold. The heights of almost all tree species inside the fence ranged between 40 and 60 cm, and though some tree heights for 9 tree species were higher than that of dwarf bamboo inside the fence, many trees outside the fence had heights of only about 10 cm. Based on these findings, it was concluded that the deer-proof fence facilitated the establishment and growth of tree species as well as the recovery of dwarf bamboo, and that the fence was an effective means of restoring cool temperate deciduous forest. Further monitoring is required to predict the future development of regenerating trees and to determine an optimal vegetation management plan.

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A/R CDM is to remove Greenhouse Gases by Afforestation or Reforestation projects of CDM, and it can be implemented in the countries such as LLDCs and AOSIS countries without large infrastructures. To evaluate the characteristics of the A/R CDM project comprehensively and consider the direction of A/R CDM, we focused on the small-scale A/R CDM project to plant Mangroves in a rural area of Fiji as a case study, and perceived and analyzed its trends and the direction of the relevant stakeholders. As a result, we found that A/R CDM cannot be easily implemented due to disadvantages such as large uncertainty and low profitability, although it has many advantages such as income generation from credits and preservation for traditional culture for villagers. The AOSIS countries including Fiji are very vulnerable to sea-level rise and the promotion of A/R CDM should be done as soon as possible, not only as a mitigation measure but also as adaptation from the viewpoint of Equity. At the next commitment period, application of Sector-based CDM to A/R CDM, reevaluation of its specific advantages such as development, and addition of incentives for project participants for the promotion of A/R CDM projects are expected.

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To clarify differences in the frequency of bark stripping and its causes, we established 16 transects in the eastern and western areas of Mt. Ohdaigahara, and examined the intensity of bark stripping, deer selection of tree species, available bark with palatability to deer, and frequency of habitat use by deer. Deer selectively debarked some tree species. While the intensity of bark stripping in the eastern area was significantly higher than in the western area, the deer-preferred species and their available bark area were not significantly different. The usage frequency of the eastern area was significantly higher than the western area. These results suggest that the high usage frequency, and in turn the high deer density in the eastern area due to the presence of Sasa nipponica, the main forage of deer, results in more severe bark stripping.

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For a general assessment of the nitrogen status of sugi plantations in Japan, we measured nitrogen content in the needles of sugi (Cryptomeria japonica D. Don) trees growing at 531 sites across the country. We attempted to find local pockets with high or low needle N and to ascertain the relationships between needle N and temperature, the rainfall environment or latitude. Average needle nitrogen content was 14.0 mg N g⁻¹ with half the sites ranging from 12.5 mg N g⁻¹ to 15.5 mg N g⁻¹; a level thought to be reasonably appropriate. Spatial analysis using G_i^*(d) statistics showed a spatial autocorrelation and indicated that needle N contents were high in two areas. These were in and around Fukui Prefecture and in the western part of the Kii Peninsula. Contrarily, needle N content was low in the mid-Tohoku district. The relationships between needle N and temperature or rainfall environment or latitude were weak. Thus, these factors cause little variation in needle N in sugi plantations across Japan.

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According to the old documents, there was awooden bridge called as ‘Hanehashi’, that was a rare type of cantilever, at the upper reach of Ohi River, Japan, in the Edo Era. The span of this bridge was kept as 72.8 m long from 1607 to 1692. But after deforestation works of forest 3,600 ha in the upper watershed, the span was extended stepwisely longer as 85.5 m in 1702 to 100.1 m in 1815. Because of the geographic conditions for the suitable base of bridge, the Hanehashi was rebuilt at almost the same place from the initial construction to the last. The authors think, deforestation works led to flood often, eroded the bank, and damaged the Hanehashi, so the span had to be extended to longer and adjusted to the width of river.

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We have developed new type compost with waste sludge from a bean curd factory and applied it to the cutting bed of Cryptomeria japonica D. Don. The effects of the compost on the elongation of root and height of cuttings were checked. No damage on rooting of the cuttings was observed in individuals containing the compost at 0.9 g N/pot. On the other hand, no elongation of height of the cuttings was observed in individuals without fertilizer. However, in the pot with the compost at the same concentration of N as above, acute elongation of the cutting height was started on 100 days after the cutting treatment and height was increased 9.2±5.0 cm further on 170 days. It seemed to be possible to accelerate significantly elongation of the height of cuttings by a fertilizer of the newly developed compost without any negative effect against rooting.

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