The vegetation history for the last ca. 100 years was reconstructed, and the influence of disturbance on the structure of vegetation mosaics was examined in an area of 100 km^2 in the Soya Hills, northern Hokkaido, Japan. The age structure of stands, charcoal fragments found beneath the litter layer, and documented evidence suggest that the forests in the study area have been disturbed severely by fires and logging since the mid-1800s. In particular, a fire that occurred in 1911,which burned almost all of the forest in this area, had a major effect on the structure of the present vegetation. While birch forest developed soon after the fire in the southern part of the study area, no forest developed in the northern part ; a large Sasa grassland (ca. 6000 ha) formed, except in valleys. One of the reasons for this difference in regeneration after the fire of 1911 was the difference in disturbance history before and after 1911. In the northern area, the forest has been disturbed by small fires and logging during the last 100 years, whereas in the southern area there has been no major disturbance since 1911 and probably before that. In addition, strong wind, which is a potential adverse factor for forest establishment in this area, has probably contributed to the formation of the Sasa grassland. Most of the relic stands and reestablished stands occupy north-facing slopes. This unique distribution of forest stands has resulted from spatial heterogeneity of disturbance operations and microsite conditions : fires did not destroy all the stands on north-facing slopes, and microsite conditions on the north-facing slopes are more suitable than those on south-facing slopes for forest regeneration after disturbance.
A method for estimating the age of habu, Trimeresurus flavoviridis, established using individuals in captivity, was applied to individuals captured in the wild. Variations of growth in terms of snout-vent length were analysed within and among several districts of the Okinawa Islands. The growth pattern of habu was similar to that of temperate snake species studied previously.
Cool-spots site vegetation was surveyed at Izariiri-Heide, near Sapporo, northern Japan. Along the gradient of soil temperature, vegetation height and species richness decreased towards the central area of Heide, where many cool-spots are distributed. Soil temperature in the central area was as low as about 4℃ even in late September, suggesting that the low temperature had enabled the subalpine Pinus pumila vegetation to become established locally in the mixed forest zone. Some stand groups in the central area were characterized by relatively abundant species richness in spite of the cool conditions. In such habitats, various forms of microrelief due to the physical characteristics of the bedrock andesite support the growth of many plant species : e. g., Sphagnum squarrosum and Sphagnum girgensohnii in wet depressions, and Vaccinium ovalifolium var. coriaceum and seedlings of Picea glehnii on dry mounds.
The geographical distribution of Persea thunbergii (Machilus thunbergii)-type forest was studied in relation to ecological factors in the Japanese Archipelago from Yakushima to Tohoku district. Persea-type forest was defined as lucidophyllous forest dominated by canopy trees of P. thunbergii, Elaeocarpus sylvestris var. ellipticus, Cinnamomum japonicum, C. camphora, Daphniphyllum teijsmannii, Neolitsea sericea, Litsea lancifolia, Ilex integra, I. rotunda, Osmanthus insularis, Prunus zippeliana, Turpinia ternata, Podocarpus macrophyllus, Ardisia sieboldii, and Ternstroemia gymnanthera. These species have endozoochorous seed dispersal by birds and are highly resistant to the action of sea wind with salt. Persea-type forest studied in 340 localities was located almost exclusively in narrow coastal areas, 300 m from the nearest coastline, as a preclimax in littoral areas affected by the northwestern winter monsoon, typhoons or severe sea wind. The forest was divided into 14 types according to the dominant canopy trees, of which P. thunbergii-dominated forest was distributed most abundantly in 246 localities. E. sylvestris var. ellipticus-dominated forest was distributed concentrically in coastal areas from the Kii Channel to the Seto Inland Sea on the Shikoku side, where P. thunbergii-dominated forest was rare. Forests dominated by C. japonicum, D. teijsmannii, N. sericea and I. integra were situated between P. thunbergii-dominated forest and the sea.