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1.
We evaluated the protective effects of floor cover against soil erosion in three types of forest located on steep slopes
under a humid climate: 22- and 34-year-old Chamaecyparis obtusa (hinoki), 34-year-old Cryptomeria japonica (sugi), and 62-year-old Pinus densiflora (red pine) stands. We measured sediment transport rates (sediment mass passing through one meter of contour width per millimeter
of rainfall), using sediment traps, before and after removing floor cover. Raindrop splash erosion was dominant in the experimental
stands. Floor cover percentage (FCP) during the preremoval stage varied from 50% to 100% among the four stands, and sediment
transport rates ranged from 0.0079 to 1.7 g m−1 mm−1. The rates increased to 1.5–5.6 g m−1 mm−1 immediately after removing floor cover, and remained high throughout the experiment. The presence of physical cover near
the ground has a crucial effect on sediment transport on forested slopes. The protective effect ratio (the ratio of the sediment
transport rate in a control plot to that in the removal plot) in a young hinoki stand, in which the FCP decreased markedly,
was 0.3 at most, which is close to the rate for bare ground. The protective effect ratio in the red pine stand was ≤0.003.
We concluded that the protective effect of floor cover in undisturbed forests in Japan differs by over two orders of magnitude,
based on comparisons with previous studies.
Received: March 11, 2002 / Accepted: August 16, 2002
Present address: Department of Forest Site Environment, Forestry and Forest Products Research Institute, Ibaraki 305-8687 Japan Tel. +81-298-73-3211;
Fax +81-298-74-3720 e-mail: miura@affrc.go.jp
Present address: Department of Forest Site Environment, Forestry and Forest Products Research Institute, Ibaraki 305-8687 Japan Tel. +81-298-73-3211;
Fax +81-298-74-3720 e-mail: miura@affrc.go.jp
Acknowledgments This study was supported by the Research Council of the Ministry of Agriculture, Forestry, and Fisheries, of Japan. We thank
H. Ujihara, S. Ujihara, and M. Ogasawara in Otoyo, Kochi, who provided the experimental stands used in this study. We also
thank K. Hirai, S. Kuramoto, E. Kodani, and the rest of the staff at the Shikoku Research Center, Forestry and Forest Products
Research Institute, for their help in conducting the experiments.
Correspondence to:S. Miura 相似文献
2.
Atmospheric lead and cadmium deposition in bulk precipitation and throughfall was investigated at four forests in the Kanto
district, Japan, to assess the impact of human activities on the environmental health of forests. Annual lead and cadmium
depositions in bulk precipitation ranged from 8.9 to 25.7 g ha−1 year−1 and from 0.77 to 1.30 g ha−1 year−1, respectively. Lead and cadmium deposition increased in the summer at every forest due to large amounts of rainfall. At one
of the forests, the depositions were also high in the winter due to heavy snowfall. These depositions were similar to recent
depositions observed at other rural and urban sites in Japan and several forests in Europe and North America after 1990. These
results indicate that although anthropogenic lead and cadmium are deposited at these rates over wide areas, depositions are
still higher than in remote areas. 相似文献
3.
Yi Min Wei Bunichiro Tomita Yasushi Hiramatsu Atsushi Miyatake Tsuyoshi Fujii Tomoyuki Fujii Shuichiro Yoshinaga 《Journal of Wood Science》2003,49(4):317-326
Poor compatibility was found between exploded wood fiber strand (WFS) and cement due to the excessive presence of water-soluble degraded polysaccharides in extractives of exploded WFS obtained from weathered wood waste treated by the water-vapor explosion process (WVEP). This study presents some comparative results from a continuing investigation on the compressive strengths of exploded WFS–cement mixtures. Based on results previously obtained with the hydration test, the relation between hydration behavior and compressive strength of the mixture was explored. In addition, the effect of the curing age on compressive strength development of the mixture with selected additive chemicals was examined. The results supported the results of early studies with hydration tests indicating that adding MgCl2 to the mixtures of exploded WFS mixed with quick-curing cement or ordinary Portland cement and a composite of MgCl2 + CaO added to the mixture of exploded WFS and furnace-slag cement effectively improved the hydration behaviors; it greatly enhanced the compressive strengths of mixtures as well. Compressive strengths were strongly correlated to maximum hydration temperatures (Tmax) of wood–cement mixtures influenced by the cement type, wood wastes (treated or not with WVEP), additive chemicals, and their content levels. The results also indicated that adding selected chemicals had no significant effect on compressive strength among the mixtures of exploded WFS mixed, respectively, with three types of cement at a curing age of 180 days. X-ray diffraction, scanning electron microscopy, and energy dispersive X-ray spectroscopy were used to identify the hydration products and to probe the element distribution of the mixture in the wood–cement interface zone from a fractured surface.Part of this report was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002 相似文献
4.
5.
Nitrogen-fixing activity in decomposing litter of three tree species at a watershed in eastern Japan
Takashi Yamanaka Keizo Hirai Shuhei Aizawa Shuichiro Yoshinaga Masamichi Takahashi 《Journal of Forest Research》2011,16(1):1-7
Nitrogen fixation during litter decomposition was studied for 34 months using litterbags containing newly fallen litter of
coniferous species Cryptomeria japonica and Pinus densiflora and that of deciduous species Quercus serrata. Litterbags were set in contact with the forest floor in a deciduous broad-leaved forest near the top of a slope and in a
C. japonica stand at the middle of the slope at a watershed in eastern Japan. Nitrogen-fixing activity, estimated by acetylene reduction
after 16 and 19 months of incubation, was 62.65–3.86 nmoles C2H4 h−1 g−1 DW in Cryptomeria litter, but only 1.07–0.09 in Pinus and 0.72–0.04 in Quercus. The rate of N increase in decomposing litter was highest in Cryptomeria. Fungal biomass in decomposing litter, estimated by ergosterol content, increased during the initial 16 months of incubation
in Cryptomeria and Quercus, and during the initial 19 months of incubation in Pinus. The litter decomposition rate was highest in Cryptomeria among the three species, due to increased N content and fungal biomass in Cryptomeria litter. Thus, N increase in decomposing Cryptomeria litter affects the subsequent N dynamics and decomposition pattern. 相似文献
6.
In vitro transcription enhancement by purified derivatives of the glucocorticoid receptor 总被引:15,自引:0,他引:15
L P Freedman S K Yoshinaga J N Vanderbilt K R Yamamoto 《Science (New York, N.Y.)》1989,245(4915):298-301
7.
8.
Jun Aoyama Akira Shinoda Tatsuki Yoshinaga Katsumi Tsukamoto 《Fisheries Science》2012,78(6):1195-1204
To determine the actual status of the recruiting glass eel stock of Anguilla japonica, we conducted a continuous monthly monitoring program for 2?years between November 2009 and October 2011 at the Sagami River estuary, Japan. A total of 114 and 372 A. japonica glass eels were observed in the 2009?C2010 and 2010?C2011 seasons, respectively. Recruitment patterns were the same in both years, starting in early winter (December in 2009 and November in 2010), increasing slightly until March, decreasing in April, but attaining the largest peak in June, after which no glass eels were observed during August?COctober. The Japanese eel has been known to spawn mainly in the summer, and glass eels recruit to their freshwater growth habitats during the winter to early spring. Our results clearly demonstrate an unexpected late arrival of glass eels in the early summer for two recent consecutive year classes. The summer recruitment found in our study indicates the unusual phenology of the Japanese eel, which may be a possible response to recent climate change. 相似文献
9.
It was reported in a preceding paper7) that the Ando soils from Uemura, Choyo, and Kawanishi contained an unknown mineral colloid which was distinctly different in some respects from coexisting allophane. In the Uemura soil, this clay fraction made up more than 20 per cent of the total clay and more than 6 per cent of the soil7). 相似文献
10.
Naganori Yoshinaga 《Soil Science and Plant Nutrition》2013,59(6):238-246
In this paper are described the properties of filmy gel substances occurring in the Imaichi (Imaichi-tsuchi) and Shichihonzakura (formerly called Jobukanuma-tsuchi (2,5)) pumice beds. The properties of such filmy materials from the Kanuma (Kanuma-tsuchi) , Imaichi, and Kitakami pumice beds have been described by many investigators (1,8, 9, 10,12, 13, 14, 15, 19, ). KANNO et al. (9) concluded that they were a mixture of poorly crystalline montmorillonite, allophane, and free sesquioxides. However, the presence of montmorillonite as an important constituent has been disproved by MIYAUCHIA nd AOMINE (12), ho concluded that the gel films from the Kitakami and Kanuma pumice beds consist principally of imogolite. 相似文献