Vegetation Science
Online ISSN : 2189-4809
Print ISSN : 1342-2448
ISSN-L : 1342-2448
Volume 19, Issue 1
Displaying 1-7 of 7 articles from this issue
  • Yasuo KONNO
    Article type: Article
    2002 Volume 19 Issue 1 Pages 1-10
    Published: June 25, 2002
    Released on J-STAGE: January 06, 2017
    JOURNAL FREE ACCESS
    To detect changes in the competitive exclusion ability of Sasa tsuboiana, a dwarf bamboo, I compared the number and total cover of associate species among habitats that had various heights and cover of S. tsuboiana on Mt. Horai (1174 m a.s.l.), 24 km northeast of Kyoto, Japan. S. tsuboiana was tall and dense on the lower slope, but decreased in height towards the upper slope. It grew short and sparse in a few places on the ridge and in the habitats disturbed through gnawing by hares and mowing by humans. The number of species per unit area was small and no herbaceous plant covered more than 1% in the tall and dense S. tsuboiana community on the lower slope. However, once S. tsuboiana decreased in abundance, more herbaceous species appeared with larger covers in comparison with the tall and dense S. tsuboiana community. These results clearly show that the competitive exclusion ability of S. tsuboiana is large in undisturbed suitable habitats, and the ability decreases when S. tsuboiana abundance decreases. In contrast with herbaceous species, woody ones did not always increase in number and total cover with a decrease in S. tsuboiana abundance. Large susceptibility of woody species to winter wind and disturbance was assumed to prevent the increases of the woody species despite decreases in S. tsuboiana abundance.
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  • Jin ZHOU, Kazuaki NAITO, Yoshitaka TAKAHASHI
    Article type: Article
    2002 Volume 19 Issue 1 Pages 11-23
    Published: June 25, 2002
    Released on J-STAGE: January 06, 2017
    JOURNAL FREE ACCESS
    Six stands of secondary vegetation at different ages from abandonment, an in-using grassland and a climax forest in upland Southwest Honshu, Japan, were surveyed in summer 1998. The grasslands of 0-2 years old from abandonment had the least species composition and one layer. Shrublands (with age of 32 yr.) had two layers in structure and were dominated by Ilex crenata and Miscanthus sinensis or Arundinaria variegata, with tree saplings colonizing among the shrub layer. The young Pinus densiflora forests (with age of 20-30 yr.) formed 3-4 layers, co-dominated with Clethra barbinervis. Mature secondary forest (with age of 33 yr.) was constructed of four layers, dominated by Quercus serrata and Castanea crenata. Fagus crenata climax forest had four layers in structure. As the age increased, height of the vegetation (as 25 m in maximum) increased, together with its complexity (four layers in its vertical structure). Both dominance degree (DD) and basal area (BA) increased till the climax (as 7438 for DD and 6109cm2 100m^<-2> for BA), while coverage of herb layer decreased to 18.3%, thought total coverage kept constant from the very beginning. Peaks of species number per plot (as 40 species 100 m^<-2> in a 32-yr-old stand), trunk density (as 115±52 100 m^<-2> in the 30-yr-old stand) and mortality (as 11.8% for trunk density, or 6.5% for BA in a 33-yr-old stand) appeared at intermediate age of the secondary succession.
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  • Toshiyuki OHTSUKA, Takeshi KIBE, Shigeru MARIKO, Kazuhiko KOBAYASHI, T ...
    Article type: Article
    2002 Volume 19 Issue 1 Pages 25-31
    Published: June 25, 2002
    Released on J-STAGE: January 06, 2017
    JOURNAL FREE ACCESS
    A newly designed free-air CO_2 enrichment (FACE) system using pure CO_2 was developed and applied to a paddy field in a cool-temperate region in northern Japan. Structural changes of weed communities in the rice paddy field under ambient and FACE (ambient+200μmol mol^<-1> CO_2) conditions were examined. Biomass of planktonic algae was small throughout the experimental period due to shallow and variable depth of flooding water in the paddy field. Elevated CO_2 slightly increased the biomass of algae, but the increment was not statistically significant. CO_2 fertilization effect on the biomass of floating weeds (Lemna perpusilla and Spirodela polyrhiza) was 3-fold in August, and 1.6-fold in September in terms of ability to exhibit vegetative propagation. In contrast, community structures of the paddy weeds (emergent and terrestrial plants) under FACE condition did not differ from that of ambient condition. CO_2 fertilization effect on the paddy weeds might be reduced by frequent human weeding and/or nutrient limitation by growth of rice plants.
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  • Yuri MAESAKO
    Article type: Article
    2002 Volume 19 Issue 1 Pages 33-41
    Published: June 25, 2002
    Released on J-STAGE: January 06, 2017
    JOURNAL FREE ACCESS
    The initial growth of Persea thunbergii seedlings was studied at a rookery site of streaked shearwaters (burrow nesters) in evergreen broad-leaved forests on Kanmurijima Island and at a non-rookery site on Jajima Island in Kyoto, Japan. Seeds of P. thunbergii collected on Kanmurijima Island in August were experimentally sown in order to survey the initial growth of the seedling. The height of the first-year seedlings of P. thunbergii in a rookery site was found to be lower than that of first-year seedlings in a non-rookery site. The height for the first-year seedlings of P. thunbergii in protected plots significantly differed from the height in unprotected plots on Kanmurijima Island. The leaf area for the older seedlings (more than one year old) of P. thunbergii in a rookery site was conspicuously small in the P. thunbergii seedlings from different regions. The total area of leaves per seedling indicated a converse J-shaped frequency distribution for the P. thunbergii seedlings on Kanmurijima Island, but indicated a normal distribution for seedlings on Jajima Island and for those sown for the experiment. This result suggests that physical disturbance of burrow nesters causes a decrease in leaf area and height in the initial stage of P. thunbergii seedling growth.
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  • Yukio ISHIKAWA, Susumu OKITSU
    Article type: Article
    2002 Volume 19 Issue 1 Pages 43-53
    Published: June 25, 2002
    Released on J-STAGE: January 06, 2017
    JOURNAL FREE ACCESS
    Growth process and age structure of Korean pine (Pinus koraiensis Sieb. et Zucc.) populations were studied in two developing mixed Korean pine-hardwood forests in northeasten China. In a plot located in Mudanfeng Forestry Area, not only Korean pine but also other species regenerated after a strong canopy disturbance in the 1950's. In Dalianzihe Forestry Area, dominant Korean pine trees in the canopy layer were established during the 1820's to 1860's. The regenerating trees in both plots originated from both seedlings and advance regenerations. However, new seedlings and saplings were not observed under the closed canopies of both plots, and only a few seedlings grew in small canopy gaps (< ca. 40 m^2 in area) created by the death of suppressed trees in the Mudanfeng plot. Thus, during the development of young Korean pine forests initiated by large canopy disturbances, seedling establishment under closed canopy or in small gaps is inhibited by insufficient light conditions. In contrast, abundant saplings regenerating in canopy gaps of old-growth forests have been also reported in several studies, and the two contrasting regeneration processes, i.e. episodic simultaneous regeneration and gap-phase regeneration were recognizable. These two regeneration processes could be located on different positions of the chrono-sequence of the development of mixed Korean pine-hardwood forests. The former process not only initiates even-aged forests, but also results in the lack of new generations in the following several hundred years. The latter process is prevalent in forests which attain the old-growth stages.
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  • Chinobu OKAMOTO, Miki NAKAMURA, Kiyotaka KABATA, Yusheng WANG
    Article type: Article
    2002 Volume 19 Issue 1 Pages 55-59
    Published: June 25, 2002
    Released on J-STAGE: January 06, 2017
    JOURNAL FREE ACCESS
    To clarify the vegetation characteristics of Stipa baicalensis communities used for mowing, we investigated the composition of the vegetation and calculated phytoecological indexes for a S. baicalensis-shrub community under mowing conditions in the steppe region of Northeastern China. The community was comprised of 37 plant species, including a shrub, Prunus sibirica, and 36 perennial species, but no annual species. The dominant species was Arundinella hirta, followed by Cleistogenes squarrosa, Artemisia scoparia, Carex duriuscula, Potentitta chinensis, Prunus sibirica, Leymus chinensis and Stipa baicalensis in the order of dominance. Vegetation coverage, Shannon-Weaver's diversity index (H') and degree of succession (DS) were 91%, 3.7 bit and 209.4 DS, respectively. The summed dominance ratio of each species (y) can be described as an exponential function of its order of dominance (x) as follows : y = 64.8 exp (-0.11 x). The mown community under consideration differed from grazed communities in containing more species, in containing some erect form and branched form species and in lacking annual and trampling-tolerant species.
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