The 1783 activity of Asama volcano was reviewed from May to the end of the year based on 166 old documents, including those recorded at a distance. 1. Prior to the 1783 Asama eruption, the level of magma head ascended at Kama-yama crater-pit. Moderately explosive eruptions commenced on May 9, and repeatedly blew off the plugged magma. 2. Depending on the wind direction, ash fell N, NNE, and NE of the crater including Sado Island, Tohoku and Kanto districts. From August 3 to 5, climactic plinian eruption dispersed pyroclastic materials. Distributions of 8 tephra- fall units were presented. 3. The timing of rumbling and quakes at distant places farther than 100km from the crater well correspond with explosive events witnessed by neighbors of the volcano. 4. Duration of a single eruptive event rarely exceed 6 hours. It was true even during the culminating plinian stage from Aug. 3 to 5, 1783. The eruption was so violent in this stage that huge blocks larger than 10m were thrown from Kama-yama crater. 5. Documents concerning with Kambara pyroclastic flow and subsequent debris avalanche occurred on August 5, suggested that an explosion on the northern flank triggered collapse of northern sector. The event occurred at about 08:00 to 08:30am, which is 90 to 120 minutes earlier than estimations appear in previous work. 6. Small and less frequent eruptions continued until January 15, 1784.

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Forest structure and dynamics were studied during 1994-1999 in a large permanent research plot (1.7ha) in a temperate broad-leaved secondary forest in Yamashiro Experimental Forest, central Japan. The forest had been established on bare land following reforestation in the late 19^<th> century. The stratification of the stand based on the M-w diagram, drawn using mean tree weight (M) and individual tree weight (w), was composed of three layers. The number of stems and leaf biomass were most heavily concentrated in the third (lowest) layer, while the first and second layers of the stand were poorly developed. The forest was therefore judged to be immature. The density and above-ground biomass in the first layer increased markedly during the 5-year census period, indicating that the forest is still developing and that the species composition and stratification of the stand are not stable. The high density and leaf-biomass in the third layer suggested that intra- and interspecific competition was strongest in this layer. The mortality and recruitment rates of the stand were 3.85% year^<-1> and 2.26% year^<-1> respectively, i.e. within the range of the corresponding values estimated for various temperate old-growth forests in Japan despite considerable differences among stand structures. The mortality rates of some early successional species such as Alnus pendula and Rhus trichocarpa substantially exceeded the recruitment rates, while that of Quercus serrata, the dominant deciduous species in the stand, was low. Because Q. serrata was represented by many saplings and was recruited substantially into the upper layers, this species is expected to maintain dominance for the time being. On the other hand, Q. glauca, an evergreen broad-leaved species, may be one of the leading candidate dominant species in the first layer because of its low mortality and rapid growth rate.

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