Using field survey data and interviews with forest owners, managers, and neighbors conducted in Hachioji and Hino, southwest of Tokyo, Japan, we analyzed the relationship between management methods and community structure in secondary Quercus serrata-Q. acutissima woodland. Our survey identified four management types according to past and present uses and the management history of the woodland: traditional management, non-traditional management, ad hoc management, and no management. Management of the forest floor, such as mowing and litter gathering, had significant effects on many attributes of the vegetation structure of the woodland. The species richness of summer-green perennials was low where management practices were interrupted for a long period. Under traditional management, there was little variation in species richness between stands, while non-traditional management resulted in greater variation. To conserve the species richness of existing woodland by non-traditional management, it is necessary to manage the woodland continuously without long periods of neglect.

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Aerial photographs were used to examine the changes in the distribution of bamboo forests in Otaki-machi, a bamboo shoot producing area in Chiba Prefecture, Japan, to elucidate the reasons for the expansion of bamboo forests in relation to the transition of bamboo shoot production, neighbouring vegetation types, slope inclination and distance from roads. In the study area (ca. 787ha), the area of bamboo forest increased between 1966 and 2001: by 1.086-fold between 1966 and 1974, 1.010-fold between 1974 and 1984, and 1.023-fold between 1984 and 2001. The largest increase occurred during the bamboo planting period; this increase slowed in the bamboo shoot production period and increased again during the decline in bamboo shoot production. Bamboo forest expansion was most frequent in abandoned dry fields, but was rare in paddy fields or inhabited areas, where people prevented the invasion of bamboo. The most rapid expansion of bamboo forests occurred on steep (>30 degrees) and inaccessible (≥150m from the nearest road) slopes that received little management. In the bamboo shoot producing area where bamboo forest management practices influence bamboo distribution, topography and vegetation conditions affected ease of management, which in turn affected the expansion of bamboo forest.

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Species composition and species richness were studied in lucidophyllous forests at their northern distributional limit in Akita Prefecture, Yamagata Pref., Niigata Pref., Iwate Pref. and Miyagi Pref., and at their upper distributional limit in Kagoshima Pref., Japan, in relation to environmental factors such as low temperature and salt breeze. In total, 79 stands in northern forest (26 on the Japan Sea side and 39 on the Pacific Ocean side), and 14 stands in upper forest (Kagoshima) were investigated. In two ordinations obtained by DCA using all occurring species, stands in northern forest and in upper forest were clearly differentiated. The northern and upper forests were differentiated by the occurrence of Cyrtomium falcatum, Persea thunbergii, Hedera rhombea, and 7 other species that were resistant to salt breeze and low temperature, and Quercus acuta, Neolitsea aciculata, Illicium religiosum and 13 other species that were non-resistant to salt breeze and resistant to lower temperature, respectively. In terms of life form spectrum, the northern and upper forests were characterized by the presence of evergreen herbs, and by the presence of lucidophyllous small trees and epiphytic ferns, respectively. The species richness (mean number of elements of lucidophyllous forest per 100m^2 stand) of forest at the northern limit, the upper limit and the distributional center (Aya, Miyazaki Pref.) were 7.0, 15.1 and 44.4, respectively. The species richness of the northern and upper forests was very low due to the low temperature. The lowest species richness at the northern limit appeared to result from environmental factors related to not only low temperature but also salt breeze.

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We have been monitoring the recovered vegetation on restored gravel bars on the Tama River from 2002. In this paper, we propose adequate habitats for self-sustaining gravel bar vegetation. For this purpose, we studied the relationship between the recovered vegetation and surface sedimentary structures and topsoil on an artificial gravel bar. We investigated the coverage and the height of all plant species, type of gravels and topsoil on the permanent quadrats. Based on our results, the recovered vegetation was divided into six community types. In these community types, Kummerowia stipulacea type was considered as a self-sustaining type among the gravel bar vegetation because of its slow successional speed. This type of vegetation occurs on open-work gravel layers without matrix, and on the hard topsoil that contains relatively high amounts of clay and silt. In contrast, on the sandy areas formed by flood deposits, exotic species such as Robinia pseudoacacia and Festuca arundinacea are increasing again.

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It is well-known that among the Castanopsis genus of Japan, Castanopsis sieboldii tends to distribute around the coastal regions and C. cuspidata distributes more inland. Although the detailed distribution pattern is unknown, the existence of an intermediate type that falls somewhere between both the species is known in the natural and secondary forests. Whether or not the intermediate type is considered a hybrid or an intraspecific variation differs depending on the researcher. This study aimed to clarify the distribution patterns of the Castanopsis species and their hybrids in 30 regions in southern Kyushu. In addition, detailed studies were conducted on the hybrid population around the coastal area of Mt. Inao, which is located on the southernmost tip of Kyushu and the Kugino Woods Tree Inheritance Resource Preservation Forest located inland. In this research, the discrimination method of the Castanopsis species based on the structure of leaf epidermis was improved by establishing the observational area of the specimen through a microscope. The following three hybrid types were distinguished based on the ratio of one-cell layers and two-cell layers of the leaf epidermis: C-type (the ratio of one-cell layers is high), H-type (the ratio of one and two-cell layers is almost equal), and S-type (the ratio of two-cell layers is high). From the results, the Kirishima region with its higher altitudes had only the distribution of C. sieboldii, and C. cuspidata showed a tendency to be distributed in the regions of relatively lower altitudes, including the inland regions. Five hybrids were found in the coastal region around Mt. Inao, and all five were S-type. On the other hand, Kugino had distribution patterns of C. cuspidata, the hybrid, and C. sieboldii in order as the altitude increased. The distribution patterns of three hybrid types were related to the distribution patterns of individuals of the mother species. The form of the Castanopsis nut was related to the distribution patterns of individuals of the mother species.

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A lucidophyllous forest on Mt. Omoridake, Aya, Miyazaki Prefecture, was studied in order to clarify the relationship between host tree size (height and diameter at breast height [DBH]) and species richness of the epiphytes on each tree. In this forest, a total of 133 trees (14 species), including 44 Quercus acuta, 23 Distylium racemosum, 22 Persea thunbergii and 44 others, were chosen as sample trees. The epiphytes on the sample trees comprised 22 species, including Lemmaphyllum microphyllum, Lepisorus onoei, Bulbophyllum drymoglossum, and Davallia mariesii. The species richness of the epiphytes on each sample tree had a high positive correlation with tree DBH (cm). This relationship was expressed by the equation: y=0.11x-1.77 (where y is the number of epiphytes, and x is the DBH (cm) of the sample tree). Species composition and species richness of the epiphytes were compared between a highland lucidophyllous forest (Omoridake) and a lowland lucidophyllous forest (Kawanaka). The ordination obtained by detrended correspondence analysis (DCA) by using all occurring epiphytes revealed that the epiphytes on the sample trees (stands) in the highland were clearly different those on the sample trees in the lowland. The lucidophyllous forest in the highland was characterized by the occurrence of L. onoei, D. mariesii, B. drymoglossum, and 9 other epiphyte species, while that in the lowland was characterized by the occurrence of Lepisorus thunbergianus, Neofinetia falcata, and 5 other species. Thus, there was significant difference in the species composition and species richness of the epiphytes between Omoridake and Kawanaka. Higher species richness of epiphytes in the highland forest appeared to the result of relatively higher air humidity at the high altitude.

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