[in Japanese]

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Hydrometric observation was conducted at the small forested catchments in order to reveal the effects of tree species and forest managements on the short-term runoff characteristics. The litter layer had became very sparse and soil surface was exposed at the cypress and the cedar plot, on the other hand, it was covered by thick litter layer and understory vegetations at the young cypress and the deciduous plot. The root layer (the upper organic soil layer permeated by fine and dense root networks) was formed at the unmanaged coniferous forests, but it was not formed at the managed young cypress and the natural deciduous forests. Responses of surface runoff at the cypress and the cedar plot were distinctly larger than that of the young cypress and the deciduous plot. Surface runoff measured at the cypress and the cedar plot was root flow (shallow preferential flow through the root layer) and it of the young cypress and the deciduous plot was litter flow, because surface runoff occurred at each plot during lower rainfall intensity (<4.0 mm/5 min) than the final infiltration rate of the soils (6.4-26.8 mm/5 min) and the shallow preferential (root flow) actually occurred at the edge of the unmanaged Japanese cypress slope during storms. ‘New water’ of each catchment would be mainly composed of direct precipitation onto the stream channel and surface runoff (root flow or litter flow) occurred nearby the stream channel, because runoff coefficient of ‘New water’ (New/P) was very small (0.2-2.0%) during both the middle typhoon storm and the small autumn rainfall. Consequently, contribution of ‘New water’ to discharge peaks and hydrological response at the unmanaged coniferous catchment (1.29 ha) was relatively larger than the other two catchments due to the root flow (shallow preferential flow pathways developed within the upper organic soil layer).

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In order to encounter the climate change, reducing CO₂ emission and increasing the CO₂ accumulation and sequestration by plants are effective measures. Promoting urban greening is also effective, and determining the amount of CO₂ accumulation is significant. Moreover, it is desirable that the estimation method is practical and applicable in reporting under Kyoto Protocol. The objective of this study is to estimate the annual CO₂ accumulation of common greening tree species for sideways and city parks in Japan. We used the annual biomass growth rate for the estimation. Dry biomass weight was measured and stem analysis was conducted. Then, annual biomass growth rate was determined based on its allometry relationship with the d.b.h. Although the previous estimation study focused on the sequestration rate of 6 species for 20 years' period, we targeted the sequestration rate of same 5 species with 1 new species for 50 years' period. The obtained data and prior study's data were analyzed altogether, and the accumulation estimation equations were developed for each species. This study shows one of the benefits of urban greening, a role of the carbon sink. It is expected to contribute in promoting the further urban greening in Japan

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Effective use of coal ash needed because coal uses for power station are increasing. As coal clinker ash (CA) are coarser than coal fly ash and CA are unlikely to scatter around, it is expecting for alternative revegetation substrate. In this report, revegetation substrate made of CA were used for pot test by revegetation woody plants, and try to show the effectiveness of substrate made from CA for cultivation. CA, peat moss and masa soil (weathered granite) were used for substrates. As masa soil and peat moss was used as control test and CA and peat moss were use for experimental test. And five tree plants (Quercus glauca, Q. phillyraeoides, Pasania edulis, Raphiolepts indica, Pittosporum tobira) were cultivated for 7 months.
Almost chemical and physical properties of substrates from coal ash were same as that of masa soil. Content and leachate of heavy metals are less than safe level decided by Japanese law. Growth rate of height (H), diame-ter (D), D²H, and weight of fresh plants were not significantly different between each treatment. Boron concen-trations of leaves grown in coal ash were larger than that done in masa soil except for one tree species. These results indicate that clinker ash can be used for substrate for revegetation woody plant, however, in actual use, characteristics of each CA were need to measure before use.

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A simple and reliable Frankia inoculation method was investigated to establish an effective rapid seedling cultivating method for pottedseedlings of Alnus hirsuta using the root-nodulating Frankia. Because the nodulation rate of Frankia in seedlings raised in commercial sterilized potting soil was low, at 30% or below, root nodules were collected from naturally growing seedlings of A. hirsuta and homogenized in tap water to produce a suspension. The nodulation rate was significantly increased by applying the suspension to newly germinated seeds. In addition, the plant height and the abundance of root nodules were positively correlated, and it was found that inoculation with a suspension having a concentration of 0.1 g/L was highly effective, and that the effects on seedling growth differed depending on the nodule sources used in inoculating Alnus hirsuta. This method is practical because it is simple and reliable. By providing suitable cultivating conditions that enhance the infection rate of Frankia and selecting root nodules infected with an effective strain with high nitrogen fixing ability, it is anticipated that it will be possible to raise such potted seedlings in less than a year for shipment.

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The land-cover change caused by desertification and re.-vegetation in Inner Mongolia from 1982 to 1999 was analyzed using a time series dataset of the normalized difference vegetation index (NDVI) derived from NOAA/AVHRR images. Comparison of the long-term change in NDVI with the actual reported vegetation change for four areas with typical vegetation cover showed good correlations. The areas consisted of stable forest cover at Daxing'anlin Diqu, in Heilongjiang Province, a large increase in vegetation cover at Aohan Banner in the city of Chifeng, a relative increase in vegetation cover at Yijinhuoluo Banner in the city of Ordos, and a decrease in sparse vegetation cover around the arid area at Ejina Banner, in Alxa League. After considering threshold values for identifying vegetation change, we concluded that the area of increased vegetation is much wider than the area of decreased vegetation in Inner Mongolia based on a map showing land-cover change using ΔNDVI, which is the difference in NDVI between 1982-1986 and 1995.1999. Aohan Banner in Chifeng showed the largest increase in vegetation cover, and parts of Xilingol League, Hohhot, and Bayannur also showed distinct increases. The total area in which vegetation increased was about 200,000 km² in Inner Mongolia. The area of vegetation increase according to ΔNDVI in each prefecture-level municipality in Inner Mongolia was proportional to the sum of the re-vegetated and newly developed cultivated areas given in yearbooks. A constant increasing trend in NDVI, caused by global warming, has been reported in the higher latitudes of the northern hemisphere. The trend toward increased vegetation cover in Inner Mongolia is mainly attributed to the expansion of cultivated and re-vegetated areas. By contrast, areas with decreased vegetation cover are widely distributed in Horqin desert and in the western arid area around Alxa League, despite a slightly negative NDVI change; this has ensued from the progress of desertification.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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