Species composing of the beech forests and their habitats were investigated on the Pacific side of central Honshu, Japan. Three associations, 1 community, 7 subassociations, and 2 subcommunities were distinguished in the area investigated. Habitats of Sasamorpho-Fagetum crenatae and the Ainsliaea acerifolia var. subapoda-Fagus crenata community were found on Mesozoic geology, and Corno-Fagetum crenatae and Hydrangeo-Fagetum crenatae on Neogene or Quaternary ones. Furthermore, the former two types were characterized by cold an inland climate with small amount of precipitation. The latter two were characterized by a coastal climate with warm temperature and high precipitation. Thus, each association was characterized by its own climatic factors as well as a geologic one. Differentiations of subassociations in the Ainsliaea acerifolia var. subapoda-Fagus crenata community and Corno-Fagetum crenatae which has a large distribution area were also corresponded with climatic factors such as temperature. However, differentiations of subassociations in Sasamorpho-Fagetum crenatae and Hydrangeo-Fagetum crenatae depended on local edaphic conditions.

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Species composition in 20 years post-fire succession on Etajima Island, southwestern Japan was investigated in five 100m^2 permanent plots based on phytosociological analysis. Twenty plant species that regenerated from sprouting organs and burned stem bases a year after the fire, consistently developed in 20 years. Therophytes such as Erigeron sumatrensis, Crassocephalum crepidioides, and Erechtites hieracifolia predominated the area and were found only in year 1. Among the invading plant species, hemicrypthophytes dominated in the shrubby stage before the young pine forest started to develop. Establishment of herbaceous plants prevailed during the shrubby stage and thereafter, the growth of such woody species as nanophanerophytes, microphanerophytes, and mesophanerophytes was improved. The diversity index of vegetation increased linearly after the fire and peaked in year 4. The index continued to rise and reached the maximum when the tree layer was developed. Seedling emergence and establishment of Pinus densiflora in the subtree layer was comparatively late compared to other broad-leaved trees. However, the susceptibility of pines to disturbance, such as fire, and their tolerance to nutrient deficient soils allowed them to enlarge their crowns and started to enter the tree layer in year 18. There was no temporal variation on the cyclic regeneration of pine forest in the area two decades after the fire. This could be traced to the frequency of fire in the region occurring in spring where pines susceptibility to fire is high due to their low foliar moisture content.

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A lucidophyllous forest in Kawanaka, Aya, Miyazaki Prefecture, was studied in order to clarify the distribution of the lucidophyllous elements and species richness according to micro-scale geomorphic and the physical-soil conditions. In this area, 5 micro-scale geomorphic units (foot slope, lower sideslope, upper sideslope, crest slope and rocky site) were recognized, and 26 stands for a vegetation survey and 8 plots for a soil survey were investigated. The 26 stands were classified into 5 stand groups according to their microscale geomorphic units. The lucidophyllous elements were assorted into the 8 species groups according to the distributional center of frequency (%) of occurrence and mean coverage (%) of each species along the micro-scale geomorphic gradient. The distributional patterns of the lucidophyllous elements in this area along the micro-scale geomorphic gradient corresponded to those in other areas. It was recognized that in many cases species of the same genus had different distributional centers along the micro-scale geomorphic gradient. Species richness (mean number of species per stand) in each stand group for the micro-scale geomorphic unit ranged from 62.6 to 44.0, and foot slope had the highest species richness which depended on the number of herbaceous plants and lucidophyllous shrubs. On foot slopes, this high species richness seemed to be due to high values of minimum air capacity, indicating highly developed soil conditions.

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Pinus densiflora is dominant on the Ken-Marubi lava flow, which was formed in 937, on the lower slopes of the north side of Mt. Fuji. However, the origin and successional history of the Ken-Marubi Pine forest were unclear. We investigated the community structures of the forest using a permanent plot at 1030m a.s.l on the Ken-Marubi lava flow, and studied the history of forest utilization by residents. Pinus densiflora predominated (79.7% of relative dominance) in the canopy layer with tree density of 912ha^<-1>. The peak of the dbh class distribution of the tree was 20-25cm, and the trees were 80-90 years old. The forest products grown on the Ken-Marubi lava flow have been utilized as fertilizer and fuel by residents from the Edo era, but were over-used in the early Meiji era (1880-90) due to the development of sericulture business. Therefore, a forest association was established and has managed the area on the Ken-Marubi lava flow as productive forest from 1915, where the residents can use sprouted shrubs and herbaceous weeds. The management of the area changed to pine forest in 1934, and started cutting all weedy trees except Pinus densiflora. In conclusion, the Ken-Marubi pine forest is not at an early pioneer tree stage of primary succession on the lava flow, but is a secondary forest established after the exclusion of artificial disturbances.

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Bud burst timing and frost tolerance were examined in Fagus crenata Blume and Quercus mongolica Fisscher ex Ledeb ssp. crispula (Blume) Menitsky, which are dominant species in the cool-temperate forest zone in Japan. The northern limit of distribution of the former species is within Kuromatsunai, Hokkaido and the latter extends its territory throughout to the northeast and interior of Hokkaido. The temperature dependence of the bud burst process was observed in Sugadaira Heights, Nagano Prefecture, for seven years. An experiment on frost effects on leaves for both species was conducted. Fagus crenata initiated bud burst earlier than Q.mongolica ssp. crispula in spring, although a strong thermal dependence of the bud burst process was observed in both species. The first leaf unfolding stage occurred on 12 May for F.crenata and on 27 May for Q. mongolica ssp. crispula. The average thermal times (TTs) for the leaf unfolding stage were 113±11℃ day for F. crenata and 182±16℃ day for Q. mongolica ssp. crispula. Experiments on freezing tolerance of winter buds and unfolded buds were carried out using a freezer and a natural-radiative-cooling box, which was newly devised for this experiment. The winter buds and buds in swelling stage were tolerant to freezing but buds in the leaf unfolding stage and the new shoot stage were severely damaged and were unable to recover. Shoots of Q. mongolica ssp. crispra formed lateral buds, which developed leaves if apical buds were damaged. These results suggest that F. crenata may not be able to disseminate in regions which may experience frost after the TT of a 113±11℃ day has occurred, bu Q. mongolica ssp. crispula can disseminate due to its delayed bud burst date and can regenerate shoots from lateral buds.

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