Japanese Journal of Forest Environment
Online ISSN : 2189-6275
Print ISSN : 0388-8673
ISSN-L : 0388-8673
Volume 48, Issue 2
Displaying 1-5 of 5 articles from this issue
  • Yoshihiro Naganuma, Hitoshi Sakio, Takehiro Masuzawa
    Article type: Article
    2006 Volume 48 Issue 2 Pages 77-84
    Published: December 25, 2006
    Released on J-STAGE: April 03, 2017
    JOURNAL FREE ACCESS
    Rhododendron aureum and R. brachycarpum are species of the Japanese alpine zone whose altitudinal zonation was determined by the last glacial stage. We compared the ecological features of the two species in a mixed community on the Yatsugatake range. A productive structure diagram showed that R. brachycarpum can absorb light efficiently by arranging its leaf mass in an upper layer and developing a more horizontal orientation of both the shoots and individual leaves in comparison with R. aureum. The C/F ratio for R. brachycarpum was 6. 52, and was almost the same value (5.99) in a mixed community. The ratio for R. aureum was lower (2.50) and decreased to 0.77 in a mixed community. Since R. aureum cannot gain sufficient light in a mixed community, its tree-ring width here was about half of that in a pure community, and there was also a decrease in the number of leaves. These results suggest that R. brachycarpum shows superior substance production in a mixed forest
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  • Atsushi Sakai, Takeshi Sakai, Shigeo Kuramoto, Shigeho Sato
    Article type: Article
    2006 Volume 48 Issue 2 Pages 85-90
    Published: December 25, 2006
    Released on J-STAGE: April 03, 2017
    JOURNAL FREE ACCESS
    We investigated the composition of soil seed banks both in an old-growth forest and an adjacent conifer plantation (Cryptmeria japonica) in Shikoku, Japan. The old-growth forest was mainly composed of temperate conifers and evergreen oaks. Twenty-nine soil samples (20cm × 30cm × 5cm in depth) were collected from the old-growth forest (10 on the ridge, 8 in the canopy gap and 11 on the slope) and 36 from the plantation. We counted emergent seedlings in the soil samples placed in an open space, and estimated the composition of soil seed banks. In the old-growth forest, there were an estimated 386 seeds/m^2 of 22 species on the slope, 158 seeds/m^2 of 11 species on the ridge and 119 seeds/m^2 of 8 species in the canopy gap. Canopy-tree species of the old-growth forest were not included in the soil seed bank except for Betula grossa. On the other hand, 383 seeds/m^2 of 38 species were detected on the slope of the C. japonica plantation showing higher species richness than the old-growth forest. It was assumed that large and intermittent human disturbance in the conifer plantation would accelerate the abundance of herbaceous species and pioneer species in the soil seed bank.
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  • Hitomi Furusawa, Teruaki Hino, Shinji Kaneko, Makoto Araki
    Article type: Article
    2006 Volume 48 Issue 2 Pages 91-98
    Published: December 25, 2006
    Released on J-STAGE: April 03, 2017
    JOURNAL FREE ACCESS
    We examined the effects of Sasa (Sasa nipponica, a dwarf bamboo) grazed by deer (Cervus nippon) or removed artificially on the temperature and moisture regime of the surface soil in a temperate mixed forest at Ohdaigahara, in southern Honshu, using four types of experimental plot, and involving combinations of deer (excluded or present) and Sasa (removed or intact). More than half of the observed values of the matric potential of the surface soil ranged between -4 and 0 kPa in all treatment plots, although the soil moisture tended to be less humid in the deer-excluded/Sasa-intact plot than in the other plots. The monthly mean soil temperature in the deer-excluded/Sasa-intact plot was 1-2 degrees lower than that in the control plot in summer, and 1-2 degrees higher than that in the control plot in winter. These results suggest that the increase in the aboveground biomass of Sasa in the deer-excluded/Sasa-intact plot induces changes in soil temperature and moisture by increasing the cover and transpiration by the Sasa. However, the differences in the environmental changes between the plots were small and unlikely to have significant effects on litter decomposition and N mineralization in the soil. As a result, the observed change in the aboveground biomass of Sasa does not seem likely to influence the nutrient cycle in this forest by changing the temperature and moisture of the surface soil.
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  • Seishi Kadowaki, Yoshikazu Endoh
    Article type: Report
    2006 Volume 48 Issue 2 Pages 99-103
    Published: December 25, 2006
    Released on J-STAGE: April 03, 2017
    JOURNAL FREE ACCESS
    Bark stripping damage to Taxus cuspidata trees (n = 179) by sika deer was examined in a plantation in the region of Southern Japan Alps in Shizuoka Pref. between 2001 and 2002. The damage was 74.9% of the trees. Diameter at breast height (DBH) of normal and damaged trees were 6.6±2.7cm (mean±SD) and 6.7±2.2cm, with no significant difference between them. DBH growth rates of normal and damaged trees for a year were 30.0±27.2% and 25.2±27.5%, with no significant difference between them. To compare the sika deer damage of Taxus cuspidata plantation to that of Cnnninghamia lanceolata in neighboring forest stand (n = 230), the damage rate and DBH of those trees were also examined. The DBHs of T. cuspidata and C. lanceolata were 6.7±4.5cm and 13.5±2.3cm in 2001, with significant difference between them. None of the damaged tree individual in C. lanceolata was observed although 44.8% (n = 103) of C. lanceolata was distributed in the same DBH classes to damaged T. cuspidata. It suggests that the occurrence of damaged tree in T. cuspidata plantation depends not on the thickness of DBH but on the difference in preference of sika deer to the tree species.
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  • Atsushi Torii, Yoshiki Shinomiya, Ryuichi Tabuchi, Shuichiro Yoshinaga ...
    Article type: Report
    2006 Volume 48 Issue 2 Pages 105-109
    Published: December 25, 2006
    Released on J-STAGE: April 03, 2017
    JOURNAL FREE ACCESS
    In order to clarify the increase in the area of abandoned cultivated land and the growth of plantations made after terrace paddy fields in a mountainous area of Tosa town, Kochi Prefecture, we analyzed the area's land-use history by using aerial photographs and performed stem analysis of planted trees. The results of land use analysis showed the area of abandoned cultivated land has increased gradually from the 1960s to the 1990s. The increase may have resulted from a political reduction of acreage and depopulation of mountainous areas. Most abandoned cultivated lands had been afforested ("terrace plantations") but those abandoned in recent years tended to be simply abandoned. We surveyed 12 plots in 12-to-33-year-old Sugi (Cryptomeria japonica) or Hinoki (Chamaecyparis obtusa) plantations that had been made after abandonment of the terrace paddy fields. Complete enumerations of each plot and stem analysis of the standard trees were carried out. The results of the stem analysis showed that the tree growth in the terrace plantations was generally excellent, both in height and in diameter, and the productivities of the abandoned paddy fields were generally classified into the sites as productivity class I. However soil conditions in the terraces tended to be too wet for these species, and it may be necessary to improve drainage by means of digging drain ditches and planting holes with enough depth to penetrate the former plowsole. The results of this study and of previous related studies suggest that terrace plantations might be presumably worthwhile for forestry as well as useful for environmental improvement, conservation of water resources, prevention of soil erosion, absorption of carbon dioxide, and so on.
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