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Street trees are one of the important components of green infrastructure in urban area. This study surveyed the relationship between introduction trends of street trees in Japan and factors such as latitude and climatic conditions. The results showed that Japanese street trees tended to be mainly broad-leaved rather than coniferous, and many of these were native species. In addition, we found that street trees not only fulfill the roles of disaster prevention and disaster reduction, but also contribute to citizen welfare and recreation because a relatively large number were flowering trees (generally planted to enjoy flowers). Also, it was suggested that Cerasus sp. are the street trees that represent Japan, because could be confirmed in all 47 prefectures. Meanwhile, Japan is categorized into four groups with characteristic street trees introduced under the influence of the latitude and temperature in each group. Particularly, while the introduction of street trees is conducted by the individual municipalities (prefectures, cities, towns, villages, and areas), similarities in the response in terms of latitude and temperature regarding the street trees in Japan are being observed beyond the administrative borders. Incidentally, weeds which invade at the base of street trees were managed by periodic weeding, instead of any special treatment, is the most common weed management strategy in Japan. In addition, installation of shrubs, artificial inorganic cover such as concrete, and equipment, etc. has also been observed and may lead to a reduction in the weeding previously mentioned.

In Japan, land readjustment projects have standardized and expanded the design and size ofrice paddy fields. These projects have simultaneously promoted the conversion of levee slopes into stableinclines by expanding the difference in levels between paddy fields, which has expanded levee slopes, i.e. theweeding area. Continuous weeding work is required to prevent erosion and the collapse of steep levee slopes,and serious accidents sometimes occur in the weeding work using brush cutters on such slopes. Brush cuttershave been popular for weeding work, but mowing machines are increasingly popular for reasons of safetyand work efficiency. However, the levee form was designed based on the assumption of using brush cutters,which recommends small horizontal standing places both at the middle and the bottom of the slope.Therefore, it is necessary to examine whether the form of the levee slope is suitable for mowing machines.We conducted weeding work experiments in two types of levee slopes (with and without standing places)using two types of weeding equipment (mowing machines and brush cutters), and the flora of the leveeslopes and the working stress on operators were investigated. Our conclusions are that (1) mowing machinesare safer and more efficient than brush cutters and (2) the conventional levee form with standing places willalso be effective for mowing machines.

Dense bamboo grasses have delayed the growth of tree seedlings after the wind damage in a natural coniferous forest in deep mountains of Kiso District, Central Japan. After suppression treatment of the bamboo grass, a native sedge Carex oxyandra replaced them and made the growth of tree seedlings worse. The technique to suppress colonized Carex oxyandra is unknown, since this sedge has not ever been a harmful weed to be controlled. Thus, we established first experimental plots for suppressing Carex oxyandraby a herbicide, glyphosate potassium salt solution (Roundup Max load) by normal levels of dilution (control without herbicide, diluted to ×25, ×50 and ×100 volume with water) in May 2010. Next experimental plots with above-normal levels (diluted to ×100, ×200, ×400, ×800, ×1,600 and ×3,200) were established in June 2011. Coverage percentage, plant height of Carex oxyandra and tree seedlings were measured in each plot in autumn up to 2015. As a result, coverage and plant height of Carex oxyandra decreased obviously after a half year in all dilution levels, and the suppressing effect continued during 2 years in the lower dilution from ×25 to ×400. However, withered leaves formed a carpet-like thick mat, which remained several years and was suspected to restrict the germination and growth of tree seedlings. Consequently, the herbicide proved out effective to the sedge for 2 years, but some additional treatment is needed to secure the foundation space for tree seedlings within the mat of withered leaves.

Alien species in the family Poaceae play an important role as cover plants for erosion control on slopes, particularly in Japan. However, concerns have arisen regarding the adverse effects of these species on the local ecosystem and biodiversity. This study therefore examined the succession and seed propagation of alien Poaceae that are used for erosion control on the cut slopes of Sakurajima volcano in southwesternJapan. The results were as follows: Although the alien species used as cover plants were dominant for the first couple of years following their introduction to the slopes, they were displaced entirely by native species after the sixth year, which is considerably faster than ordinary succession. In addition, heading (flowering) of alien species was also rarely observed in this period. It is considered that the observed results were caused by the oligotrophic conditions of the slopes on Sakurajima volcano.

Many old trees were blown down by typhoons in 1959 and 1961 in a natural coniferous forestdeep in the mountains of Kiso District, Central Japan, and dense dwarf bamboo subsequently delayed thegrowth of tree seedlings. Forest engineers have tried to suppress dwarf bamboo to promote the regenerationof arboreal vegetation. However, after suppression of dwarf bamboo, an unknown grass unexpectedlycolonized the area and replaced them. Afterward, almost no tree seedlings could be observed in the newlyformed community, which seemed to worsen the extent of regeneration. It has been identified that the grassas Carex oxyandra, a native sedge species indigenous to Kiso District. Commonly, Carex oxyandra grows asshort as about 10 cm like lawn grass, but it seems to have exceedingly enlarged the size in the community.Thus, investigation on the morphological variation of this sedge in Miure Experimental Forest within theKiso National Forest was carried out. Leaf blade length, basal tiller length, and number of leaves per tillerwere measured in upper and lower stands on three slopes in 2009. Results revealed that leaf blade length andbasal tiller length in lower stands were approximately twice as large as those in upper stands on each slope,whereas the number of leaves per tiller was almost the same (8.8-9.4 leaves). Consequently, tussocks of thissedge became large in lower stands on a slope, which made the community overcrowded and damp,restricting tree regeneration.

As a part of an ecological research project on wild animals, alpine steppe vegetation in the Koyondu Valley, the Sarychat-Ertash State Reserve, in the northern Tian Shan Mountains of the Kyrgyz Republic was surveyed. Horses and sheep were kept as livestock, while wildlife such as Marco Polo sheep (argali) and wolves also inhabited the region. Information regarding wildlife, weather conditions and the livelihood of human inhabitants within the region was scarce and difficult to obtain. In May 2011, 21 releve plots from 5 types of vegetational physiognomy were established at elevations ranging from ca. 3,400 to 3,600 m. In each plot, coverage, sociability and height of each plant species were measured. As a result, vegetation physiognomy of type IV plots (grassland with accumulated detritus) proved to have by far the greatest coverage and v-values of all physiognomy types. Seven varieties of plant community (A1 to A4 and B1 to B3) were recognized based on differing combinations of 4 differential plant species. Varieties of plant community did not exactly correspond to types of vegetation physiognomy, and type IV plots displayed the most variability. Distribution patterns of each community in relation to elevation and slope direction appeared similar on both the left (facing southwest) and right (facing northeast) banks of the valley, but exceptions were observed more frequently on the left bank than the right. When v-value was plotted against the total number of plant species present, the majority of plots fell within a successive transition. Type IV plots, however, were out of this transition and possessed exceptionally abundant vegetation.

Typhoon 9512 hit the island of Mikura-jima in 1995, causing many landslides and destruction of forest vegetation. For long-term observation of vegetation change, a research plot was established on a landslide slope in 2003. A simple terrace was built on this slope, which was planted with native species (Alnus sieboldiana and Miscanthus condensatus) in 2000 to accelerate vegetation recovery. From 2003 to 2012, a vegetation survey of the plot was conducted to elucidate the vegetation recovery process at an early stage. A. sieboldiana grew steadily and its density of individuals decreased. The number of species gradually increased due to invasion of new seedlings from adjacent forests, i.e. Castanopsis cuspidata, Persea thunbergii. We found some differences in vegetation recovery from another research site, which is a landslide slope seeded with exotic pasture grasses by helicopter in 2002. Seeding of exotic pasture gasses prevented the establishment of trees and reduces successional velocity.

In order to clarify the factors affecting the species diversity of plant communities around an irrigation pond, we surveyed Obaste-oike Irrigation Pond in Nagano Prefecture, Japan. The pond is comprised of three subdivided ponds, Kami-ike, Naka-ike, and Shimo-ike. Despite being adjacent to each other and connected by streams, the water levels in the three ponds differ. Five plant communities were studied, and one or two survey plots were selected in each community along each subdivided pond. A 32-m 2 quadrat was established in each plot of grassland, and a 400-m 2 quadrat was established in each plot of forest. The results of the distribution of species revealed that approximately 40% of the species were endemic to each subdivided pond in the terrestrial communities, whereas over 60% were endemic in the hydrophytic communities. To increase species diversity in irrigation ponds, especially in hyrdophytic communities, we suggest that dividing the ponds into several zones with distinct water levels and managing them in a sustainable manner is important.

Typhoon 9512 hit Mikura-jima Island, Izu Islands, Japan in 1995, producing many landslide slopes. Torino-o No.3 landslide slope was fascined with fallen trees and planted with seedlings of native species (Alnus sieboldiana tree and Miscanthus condensatus grass) as part of vegetation recovery efforts, and was subsequently seeded by helicopter in 2002 with exotic pasture grasses. To elucidate the influence of fertilization on the growth of transplanted seedlings of native species, exotic pasture grasses and newly invading trees and herbs, we designated seven plots in 2004, and surveyed vegetation every summer until 2013: four fertilized plots (fowl manure applied at 0.2 g/m 2 ) and three non-fertilized plots. The native species seedlings grew steadily irrespective of fertilization, but with self-thinning in A. sieboldiana. Exotic pasture grasses decreased gradually and almost disappeared in 2013. Fertilizing temporarily enhanced the growth of some species, but seemed to induce species competition, judging from the delay of invading of native trees and the increase of climbing plants in herbaceous layer in fertilized plots.

Growth and reproductive yield of Yabumame (Amphicarpaea edgeworthii Benth.), a geocarpic edible wild legume, were investigated by field experiments. In experiment 1, seedlings of subterranean seeds derived from a natural habitat were transplanted to the field at a hill space of 30 cm within a row and 45 cm interrow spacing with 3 levels of support poles. A significant difference was observed in the increasing rates in the number of main-stem leaves between the plants with and without support poles since the 30th day after germination, when spiral elongation of their main stems started. The yield of subterranean seeds was approximately 20 gm-2, but the total reproductive yield including aerial seeds was 40 g m-2 The latter had a highly positive correlation with the total number of leaves. However, the plants with over 120 leaves per m2 to produce more aerial seeds than subterranean seeds. In experiment 2, the growth of seedlings of aerial seeds (SA) was compared with that of subterranean seeds (SS). SA and SS were transplanted to a level field with 1 plant per 1 m2 During the vegetative growth, the increasing rates of main-stem leaves were SA=SS, but the specific growth rates in total number of leaves were SA

The objective of this study is to collect basic information on vegetation in road crack, especially in curbside crack of road, for evaluating plant biodiversity in urban landscape. A curbside crack in this study was defined as a linear space (under 20 mm in width) between the asphalt pavement and curbstone. The species composition of plants invading curbside cracks was surveyed in 38 plots along the serial National Route, over a total length of 36.5 km, in Fukuoka City in southern Japan. In total, 113 species including native plants (83 species, 73.5%), perennial herbs (57 species, 50.4%) and woody plants (13 species, 11.5%) were recorded in curbside cracks. Buried seeds were also obtained from soil in curbside cracks, which means the cracks would possess a potential as seed bank. Incidentally, no significant differences were found in the vegetation characteristics of curbside cracks among land-use types (Kolmogorov-Smirnov Test, P > 0.05). From these results, curbside cracks would be likely to play an important role in offering habitat for plants in urban area.

How plant seeds secure root penetration into soil to obtain good seedling establishment is one of the basic ecological problems. In this study, seminal root growth was investigated to clarify the cause of varietal difference of seedling establishment in direct seeding of rice in flooded paddy fields, with special reference to root tip rotation. In a field experiment, seedling establishment percentage had a weak correlation with seminal root elongation rate but was not correlated with apparent seedling weight in water, which has been reported to be the cause of floating seedlings resulting in poor seedling establishment. Root tip rotation was analyzed for indoor-grown seedlings using spectrum analysis: the maximum entropy method (MEM) was used. Maximum entropy method power spectrum analysis clarified that maximum MEM power density (practically corresponds to spiral angle) detected in the frequency range above 0.1 cycles mm-1 was highly and positively correlated to seedling establishment percentage in the field experiment. Maximum MEM power density in high correlation with seedling establishment was mostly found around frequencies of 0.2 cycles mm–1, which corresponded to 2.0–3.4 cycles of root tip rotation per day. From these results, root tip rotation (circumnutation) with a larger spiral angle was suggested to play an important role in the establishment of rice seedlings on flooded and very soft soil. A possible explanation for why a larger spiral angle was advantageous for seedling establishment is that if buoyancy and seedling weight are constant, a larger pushing force of the seminal root is available without causing floating of a seedling, due to the upward force being a reaction of the seminal root pushing force.

The relationships between the climbing growth and the seed production in yabumame (Amphicarpaea edgeworthii Benth.) were analyzed based on the phytomer concept. An intensively positive correlation was found between the number of subterranean cleistogamous flowers and phytomers. The plasticity of branching construction (H) was influenced by the number of phytomers, whereas the entropical plant type index (H') and the plasticity of phytomer elongation (PE) were not affected. The H' of secondary branches significantly correlated positively to the number of aerial flower pods. The PE of primary branches close to the ground significantly correlated negatively to flowers per phytomer. The numbers of aerial and subterranean phytomers were under such an allometric relationship that the number of aerial phytomers had a significant correlation with the number of penetrated subterranean phytomers (PS), a lower correlation with the number of cotyledonary subterranean phytomers (CS), and the most intense correlation with the total (PS+CS). So CS was presumed to compensate subterranean growth. The PE of primary branches close to the ground correlated negatively to the aerial-phytomer penetration percentage into soil, revealing the trade-off relationship between the emigration by climbing stem and the settlement by penetration into soil. The relationship between PS and CS and variations in H' and PE is appreciated as clues to improve the plant type and seed allocation to geocarpic seed production around the root for domestication.

湿生植物を用いた水域緑化が近年数多く試みられるようになってきた。本報では, 湿生植物の生育に配慮した水域緑化について検討することを目的に, その基礎的研究として生花苗沼湿原に自生するヨシ (Phragmites australis), フトイ (Scirpus tabernaemontani), マコモ (Zizanialatifolia), ガマ (Typha latifolia) の生育環境を主成分分析により解析した。その結果, マコモおよびフトイは, 土壌が無機質に富み水位変動が大きい立地に多く生育した。さらに, 両種は海水が流入する立地, 水深が深い立地にも生育した。ガマは, 土壌が有機質に富み水位変動が小さい立地に多く生育した。ヨシは, 土壌の性質や水位変動に規制されず幅広い立地に生育した。

Strains of yabumame (Amphicarpaea edgeworthii Benth.), an edible resource of geocarpic wild legume, were collected from various stands in Japan and grown to investigate the geographic variations in its flowering and ripening behaviors. Northern strains needed fewer days after sowing to flower. The flowering period lasted longer for northern strains, where the duration varied among strains. Significantly negative correlation existed between days after sowing to flowering and flowering duration. The average 1.000-seed weight including all strains was 22g for aerial seeds and 143g for subterranean seeds. The former was a hard seed since scratching the seed coat increased the germination percentage sharply, whereas the latter germinated at high percentage without any pretreatment. The 1, 000-seed weight did not correlate with the latitude of home habitat. Subterranean pod including 2 mature seeds, twin bean, was produced at a higher probability in the case of the strains which had a heavier 1, 000-seed weight. The degree of subterranean seed to the total of its number and weight correlated vaguely to the latitude of each strains's home habitat. The deviation of the rate among strains was wider in southern strains.

To elucidate the relationship between the seed production of yabumame (amphicarpaea edgeworthii Benth.) and the micro-envivronment of its habitat, vegetation and external leaf morphology (leaf color, leaf area, density of pubescence, and pulvinus color) were investigated for indicating indirectly the latter. In addition, the association between taxonomic groups and seed production was reviewed since leaf morphologies were criteria for the taxonomy of varieties in A.edgeworthii. A stand of each strain's home habitat was surveyed by ordination concept based upon the biological spectrum. Degree of succession (DS) was calculated from the spectrum of Raunkiaer's dormancy form. Most of the stands were kept at rather intensely disturbed states so that the DS was between 5 and 10. The percentage of rosette species was calculated in each stand from the spectrum of growth form. Among the stands, 0.15 to 0.30 of the percentage was outstanding. This percentage had a significant negative correlation with 1, 000-seed weight. The leaf morphologies were vaguely associated with vegetation and seed production. It was confirmed that distributions of strains of thinly pubescent, blackish-purple pulvinused leaves with grayish-green backs were geographically localized. Since this pattern was similar to what had been reported for A.edgeworthii var. trisperma, it appeared that the leaf traits were the criteria by which the varieties were judged. As we failed to correlate those leaf traits with seed production, it is not considered to be possible to use the differences in geocarpic seed production as their traits of the 2 varieties.

As a threshold to investigate the climbing growth relative to seed production in yabumame(Amphicarpaea edgeworthii Benth.), the plant size, branching construction, and elongation of the climbing stem were analyzed with reference to phytomer concept. Four strains with different characteristics of seed production were grown for 150 days and harvested during their flowering period. Branching development was observed up to the 4th order. The production of branches and phytomers were maximal at the secondary order in each strain. A significant difference was detected among strains in the number of main-stem phytomers and in the number of primary branches. Since the branching pattern was too complex to analyze, the plasticity of branching construction(H)and the plant-type index(H'), based on entropy, were calculated in each branch order. H was maximal at secondary branches, and H' increased as the branch order rose in each strain. A significant difference existed in H and H' of primary branches among strains, and the two significantly correlated positively. Branches were classified into "aerial" and "close to the ground." The plasticity of phytomer elongation(PE) was calculated on the basis of range among phytomer lengths and the F-value by linear prediction applied to those as serial data. The PE of primary branches close to the ground was significantly different among strains. The order of PE magnitude between aerial branches and close-to-ground branches was dissimilar among strains. The plasticity of branching construction and of phytomer elongation appeared to have different ecophysiological backgrounds, since neither H nor H' hardly correlated to PE value.