Other than artificial forests, three major types of lucidophyllous (evergreen broad-leaved) forests are found in Japan, according to the degree of human impact: (1) primeval; (2) natural-those that have been subjected to occasional low-impact human disturbance, such as tree or understory cutting, and to a high degree of fragmentation by human development; and (3) secondary-coppices that was used as a source of firewood and charcoal. In this study, species composition and richness were compared among primeval, natural, and secondary lucidophyllous forests on Tsushima Island, Japan, to clarify the effects of human disturbance and forest fragmentation. The vegetation of 76 plots of 100m^2 (30 primeval, 20 natural, and 26 secondary plots) was investigated. The results of detrended correspondence analysis showed that: (1) the species composition clearly differed among the forest types; and (2) the species composition of the natural forests was in between the compositions of the primeval and secondary forests, showing similarities to both. The differences in species composition among the three forest types seemed to greatly reflect the degrees of both past human disturbance and forest fragmentation. Distylium racemosum, which has a low coppicing ability, dominated in the primeval forests, but this was not or rarely the case in the natural and secondary forests. Species richness (number of species per 100m^2) differed significantly among the forest types, from highest (primeval) to lowest (secondary). The number of all species per 100m^2 did not have a clear relationship with forest fragmentation. However, the number of species whose distributions were biased toward the primeval and natural forests was highly and positively correlated with patch area of the primeval and natural forests, suggesting that forest fragmentation is partly responsible for the differences in species richness among the forest types.

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The floristic composition and environment of riparian forests consisting of Lagerstroemia subcostata var. fauriei (LSF), an endangered species, was investigated on Yakushima Island. Based on data collected from sample stands located in 35 riparian and 46 slope positions, four main species guilds (an upper evergreen forest guild, a lower evergreen forest guild, a ridge type and a pioneer/wetland guild) were detected using cluster analysis. LSF was identified as a component of the pioneer/wetland guild. TWINSPAN indicated compositional differences between typical evergreen broadleaved forests and secondary or wetland forests. The classification divided the 35 riparian stands into five of the eight types, including three stands classified as evergreen broadleaved forest. This variation in species composition within the riparian forest reflected characteristics of the site environment including watershed area, river width, sedimentation width/river width ratio, and elevation. LSF occurrences were limited to the stands on riverbed sediments and the foot-slopes of small watersheds (area<ca. 500ha), indicating the importance of sedimentation for the establishment of riparian forests consisting of LSF.

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Distribution of woody species along environmental gradient in a subtropical oceanic island (Hahajima Island in the Bonin Islands) was studied. Vegetation data were analyzed by an ordination technique (CCA, canonical correspondence analysis), and distribution of species abundance on the ordination axes was calculated. Environmental gradients which related to moisture condition affected the species distribution. Maximum abundance and niche width were calculated from the species distribution on the ordination axes. Ardisia sieboldii, Rhaphiolepis indica var. umbellata, Bischofia javanica, Planchonera obovata had wide niche and relatively high abundance. On the other hand, the shrubs which appear on windy ridges tend to have narrow niche width and high abundance. Two alien species of B. javanica and Morus australis had different niches. Niche overlap by alien species with native species was calculated. Niche of B. javanica overlapped with 15 species out of a total of 31 major woody species, and with seven species by M. australis.

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In the upper reaches of the Ina River in the Hokusetsu area of Hyogo and Osaka Prefectures, the celebrated Ikeda-zumi (Ikeda-charcoal), which is used in the tea ceremony, is still made from the wood of Quercus acutissima. A historical study of ikeda-zumi and the fuelwood forest in this area was carried out by reference to ancient documents and publications, and also from a vegetational viewpoint. Descriptions of ikeda-zumi were confirmed in ancient documents and publications dating back to the 15th century, describing Hitokura as a charcoal-producing district, and Ikeda as a charcoal collection and distribution center. It was also documented that ikeda-zumi was used in the tea ceremony by Ashikaga Yoshimasa, Senno Rikyu and Toyotomi Hideyoshi, and that a coppice forest composed by daiba-kunugi (pollarded Quercus acutissima) in this area was cut in rotation with a cycle of 8-10 years. The distribution of the Quercus acutissima forest in Hitokura, Kurokawa, Kunisaki, Yoshikawa and other areas was recorded in the enpo-kenchicho (Enpo land survey register) in the 1670s. Descriptions referring to ikeda-zumi and the fuelwood forest in these ancient documents and publications were in accord with the present state of ikeda-zumi fuelwood species, the charcoal-producing district, the distribution of Quercus acutissima, the planting of Quercus acutissima, the existence of daiba-kunugi, and the forest rotation cycle. It is clearly important to maintain this traditional landscape of Quercus acutissima forest in the upper reaches of the Ina River, which has provided fuelwood for the best quality charcoal ikeda-zumi from the Muromachi era up to the present.

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Thalassochory potential was investigated for fourteen plant species (eleven native species and three alien species), which were dominant and/or characteristic species of coastal sand dunes in the warm temperate zone in Japan. The buoyancy and the viability of their disseminules in sea water (simulated by 3.45% sodium chloride solution) were examined in a laboratory. Fruits of Fimbristylis sericea did not float in sodium chloride solution, suggesting that this species would not be dispersed by sea currents. Grains of Ischaemum anthephoroides and Zoysia macrostachya floated for about ten to twenty days, suggesting that these species would be capable of dispersion by sea currents for a short period. Fruits or seeds of the other native coastal plants, i.e. Lathyrus japonicus, Glehnia littoralis, Calystegia soldanella, Vitex rotundifolia, Ixeris repens, Wedelia prostrata, Carex kobomugi and Carex pumila, continued to float and remained in sodium chloride solution for at least two months, suggesting that they would have high potential for thalassochory. On the other hand, disseminules of three alien species, Oenothera laciniata, Diodia teres and Lolium rigidum, did not float in the solution, suggesting that these alien species would not be dispersed by sea currents. However, these alien species can also be distributed in inland habitats, and they can be dispersed from inland seed source to coastal sand dune areas. If fragmentation of coasts takes place artificially and disrupts the structure of meta populations, native coastal plants which have limited capacity for thalassochory will disappear, since their disseminules would not be able to migrate again following extinction of the local population.

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