In an attempt to investigate urban wetland ecosystems, the pattern of vegetation distribution and its causative factors were analyzed on abandoned cultivation land in the Minuma-tambo, located southeast of Saitama prefecture. Phragmites australis (Cav.) Steud. communities were distributed throughout the investigated area in 1998. However, Solidago altissima L. subsequently invaded the area and P. australis (Cav.) Steud. communities only remained distributed around water bodies by 2006. Furthermore, it was determined that the causative factors of vegetation distribution are mainly linked to site factors such as groundwater level, inclination of ground level, and soil hardness. P. australis (Cav.) Steud. communities were distributed in areas with high groundwater levels, while S. altissima L. communities were distributed in areas with low groundwater levels. However, S. altissima L. communities were distributed in areas with high groundwater levels if the ground level inclination and soil hardness were also high. The abandonment of cultivation, an artificial water system constructed in 2000, and trampling have permitted S. altissima L. to invade these areas and, as a result, the vegetation distribution has changed significantly.

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The present study examined the essential features of local heavy rainfalls observed in Tokyo on July 4, 2000. The following results were obtained: 1) The atmosphere was unstable while the Japanese islands were covered by the Pacific high. 2) The easterly surface winds converged with southerly winds (E–S-type wind system) in the central part of the urban area several hours before the precipitation occurred. 3) The cold air outflow associated with the precipitation system flowed into the convergence zone formed by the E–S wind system.
Examining the spatial distribution of and temporal change in the precipitable water vapor (PWV) on the Kanto plain shows that the PWV tends to increase before rainfall occurs both over the mountains and on the plain. However, it does not appear that the PWV increased in Tokyo due to the urban heat island circulation. Therefore, the urban heat island did not produce heavy rainfall by inducing a strong upwind and drawing in water vapor in this case.

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This study discusses the relationship among the expansion of paddy fields, households, physical environment, and agrarian policy since 1952 in Dong Khuai village, on the Vientiane plain in central Laos. In this village, approximately 90% of households were engaged in rain-fed lowland rice production, primarily for self-sufficiency, in 2005. The expansion of the rain-fed paddy fields corresponds with the increase in the number of households. Rain-fed paddy fields increased by about 4.3-fold in the 54 years between 1952 and 2006. This expansion was particularly rapid between the 1980s and the 1990s, when the paddy fields reached lowland areas prone to river water flooding in the rainy season.
Due to an agrarian policy for the collectivization of agricultural production, an agricultural organization was set up for rain-fed lowland rice production involving all farmers in Dong Khuai village in 1979. However, many farmers were dissatisfied with the distribution of production, and most households withdrew from the organization within one year. Therefore, the policy did not contribute to the expansion of the paddy fields. On the other hand, a few households remaining in the agricultural organization began floating rice cultivation and introduced dry-season irrigated rice production. As a result, rice production in the area diversified. The floating rice cultivation and dry-season irrigated rice production continued after the dissolution of the organization, and many villagers became involved. Nevertheless, the area covered by irrigated paddies has increased only slightly since 1997. The planted area of irrigated rice in the dry season was adjusted in line with rainy season production and the cost of managing and maintaining the irrigation system. Dry-season irrigated rice production also serves as a safety net to compensate for poor harvests in the rainy season.

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The purpose of this research was to determine the differences in age structure and aging process among detached residential estates developed in the 1960s in the city of Sendai, Japan, and to identify the elements affecting the differences.
In 1975, there were differences among the estates in terms of population composition by 5-year age-groups. In this research, these 24 estates were classified into three types by age structure in 1975 through cluster analysis: residential estates dominated by the first and second generations (type 1); residential estates with a nonbiased age structure (type 2); and residential estates with more young people around 20 years old (type 3). Analysis of variance showed that the differences in age structure were closely related to the attributes of the estates, particularly the distance from Sendai station.
From 1975 to 2005, type 1 estates experience rapid aging of the population as the first generation grew older and the second generation moved out, and therefore it recorded the highest ratio of the elderly as well as the highest average age of residents. These estates are generally located relatively far from Sendai station in general and received fewer recent migrants, resulting in a considerable population decrease. Meanwhile, the estates within a short distance from Sendai station experienced a noticeable inflow of young people and did not necessarily undergo a very rapid aging.

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Moso bamboo (Phyllostachys pubescens Mazel ex Houzeau de Lehaie) is invading woodlands and farmlands throughout Japan as human activity decreases in these locations. To elucidate how changing human impacts on bamboo groves and adjacent land have influenced bamboo grove expansion, I investigated changes in vegetation, land use, and edible bamboo shoot production in Kofuki, Takehara, Hiroshima prefecture, Japan. Bamboo shoot production prospered in this region from the late 1970s to the early 1980s. By the late 1980s, bamboo shoot production was in decline due to decreased demand caused by increased imports from China and the aging of the forest workforce. However, between 1962 and 2000, the area of bamboo groves expanded 2.6-fold, with bamboo invading dry fields and orchards adjacent to existing bamboo groves. These lands were open to bamboo grove expansion after undergoing land-use or vegetation changes. Thirty-six percent of the bamboo grove expansion area was changed from farmlands between 1962 and 2000. Although some owners in this region had enlarged bamboo groves prior to the 1980s, most of the expansion was due to the invasion of bamboo into adjacent forests and, especially, abandoned fields.

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