The nitrogen contents of cotyledons per seedling of Pinus densiflora and Cryptomeria japonica reached a peak at 10 days and 20 days after germination, respectively, and subsequently decreased. The chlorophyll and Rubisco contents reached a peak later than the nitrogen contents at 20 days and 30 days after germination, respectively. The fertilization level did not affect the cotyledon weights per seedling. The nitrogen, chlorophyll, and Rubisco contents per seedling, however, increased significantly due to fertilization. These results indicate that the increase due to fertilization during the photosynthetic production by the cotyledons would be translocated to the other organs of the seedlings. With regard to the growth responses of each tree species to fertilization, the differences between species were significant in the following two aspects: the photosynthetic capacity under non-fertilization and the magnitude of increases in photosynthetic capacity caused by fertilization. As compared with the mature needles of the other seedlings or saplings of conifers, in this study, the cotyledons that were treated had considerably high nitrogen content ratios on the basis of weight, and similarly, high chlorophyll content ratios, while the Rubisco content ratios were at an intermediate level. In these cotyledons, the ratios of chlorophyll or Rubisco contents to the nitrogen contents were high in the former and low in the latter.

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The preservation of the forest ecosystem is very important in Shirakami-sanchi World Heritage. The influence that the visitors have in the area is becoming a problem. Therefore, it is necessary to develop an effective method of management for protection of the World Heritage. In the present paper, we clarified the visitors' dynamics and attribute in the Shirakami-sanchi area. The study was conducted at Anmon Falls, Mount Shirakami-dake and Mount Futatsumori at 1996-1997 and 2001-2002. Data was collected by a count investigation and questionnaire survey for visitors. The major findings were as follows; i) The number of visitors was 292-1269 a day. The Anmon Falls was visited by 80 percent of the visitors. ii) A large number of visitors were middle aged and accompanied by family. iii) Where the visitor's resided and how often they visited the forest were related to the place and season of the visit. iv) The visitors could be classified by their residence and the frequency of visits to the forest. v) During the past five years, the characteristics according to site have become obscure, and the visitors from far away are coming to visit the World Heritage.

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The tenth-year growth of 24 F1 families that combined five elite trees with superior growth (SG) and five snow-resistant (SR) Japanese cedar (Cryptomeria japonica) was analyzed. From an investigation of the tree height of 10-year-old progeny in a test plantation, seven F1 families with superior growth traits in terms of both tree height and snow resistance were selected. Four growth factors were analyzed: tree height (H), stem diameter at breast height (DBH), horizontal length between the centers of DBH and stump (BHLH), and mortality rate (MR). The analysis showed that all four factors were closely related to the indicator BHLH/H. The growth and snow-resistance traits of 24 Fl families were evaluated using this indicator. “Yuri-10” and “Yamamoto-3”, which are elite trees with superior growth, and “SR-26” and “SR-50”, which are snow resistant, contributed to breeding F1 families that were superior in both growth and snow resistance. ANOVA of these growth traits for F1 families obtained by breeding four female snow-resistant trees and male superior-growth trees following a factorial design showed that i) H, MR, and BHLH were significant in both elite trees, ii) DBH was significant only in elite trees with SG, and iii) BHLH was significant only in snow-resistant trees. The interaction between male and female trees was significant for all four factors. This suggests that the specific combination of male and female trees is very important in a breeding program.

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In this study, mixed stands of Cryptomeria japonica and Zelkova serrata were planted with the aim of creating a forest with Zelkova trees in low density. The sites used in the study are located in northern Akita Prefecture. Seven research sites were planted by gradually adding Zelkova trees to the sites which have initially been planted with Cryptomeria trees. The additional planting of Zelkova trees in each site followed a set planting sequence in intervals of 0, 2, 3 or 4 years. The planting density of Zelkova trees in the individual sites varied between 400 to 600 trees per hectare. The growth patterns of each species of tree were observed in the individual sites for a total period of 10 years. The resulting Zelkova tree growth demonstrates that optimal growth for Zelkova trees in such mixed stands results when Zelkova trees are initially planted together with the Cryptomeria trees.

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Annual fluctuation in seedfall and seedling dynamics of Fagus crenata was investigated over an 11 year period (1993-2003) at the Ohtakizawa Research Site, Shizukuishi, Iwate Prefecture, in order to examine the masting habit, pollination efficiency in relation to amount of flowering, pre-dispersal seed predator satiation by insects, and postdispersal generalist predator satiation. A great quantity of sound seeds (>94 m^-2) was produced in 1995, 2000 and 2003, while there were 5 years with no sound seeds. The proportion of sterile seeds did not significantly correlate with the number of staminate inflorescences. This tendency does not support the pollination efficiency hypothesis. The proportion of insect-damaged seeds by moth larvae, Pseudopammene fagivora, was negatively correlated with the number of fertilized seeds (sound seeds and insect-damaged seeds, etc.), and with the ratio of fertilized seeds in year N to those in year N-1. These tendencies support the predator satiation hypothesis at the pre-dispersal seed stage. On the other hand, there was no significant correlation between the number of sound seeds and the seedling emergence rate, or between the number of emerged seedlings and the seedling survival rate until the autumn of the same year. Such facts do not support the predator satiation hypothesis at the postdispersal stage. The failure to escape from postdispersal predators may be affected by the loose synchrony in annual seed production of co-occurring tree species (e.g., F. crenata, Aesculus turbinata and Quercus crispula) that share common predators (rodents).

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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