蔵王連峰のオオシラビソ林で発生した集団枯損の広域把握と枯損後の更新  [in Japanese] Large-area Mapping of the Mass Mortality and Subsequent Regeneration of <i>Abies mariesii </i>Forests in the Zao Mountains in Northern Japan  [in Japanese]

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Abstract

<p>林床にササが優占する蔵王連峰のオオシラビソ林では,穿孔性昆虫による局所的な集団枯損が発生している。本研究では,山形県側に分布する528 haの同種の森林を対象に,衛星画像を用いて各50 mメッシュ内にある個体の枯損率を調べ,GISにより集団枯損の分布と対応する立地を検討した。枯損率60%以上のメッシュが集中する地区は大別して3カ所あり,その大部分は高標高域の西側斜面に位置していた。しかし,同立地の多くは枯損率が20%未満のメッシュであったため,集団枯損の局所的な発生を立地条件だけで説明することはできなかった。28個のメッシュ内に調査区を設定し,ササの林床被度と後継樹密度との関係を調べたところ,ササが密生するほど同種の実生や稚樹の数は減少した。ササの被度は標高が上がるにつれて増加する傾向があり,後継樹密度は高標高域で低かった。その傾向が顕著であった地蔵岳の西側斜面は,高標高域に枯損率の高いメッシュが最も集中しており,枯損林内に設定した調査区には実生や稚樹がまったくなかった。したがって,地蔵岳西側斜面の集団枯損林はその後の更新が困難と予測された。</p>

<p>Mass mortality caused by bark beetles occurred locally in a subalpine fir (<i>Abies mariesii</i>) forest in the Zao mountain area in northern Japan. We examined the distribution of the mass mortality of <i>A. mariesii</i> trees and the corresponding locations to analyze the mortality rate in each section of a 50 m mesh, using satellite images and GIS, in a 528 ha fir forest in Yamagata Prefecture. Our results show that there were three areas where sections with mortality rates of 60% or more were concentrated in this study area. They were located on western slopes with high altitude. However, since there were still many sections with low mortality rates in these locations, the local occurrence of mass mortality could not be explained by location alone. Sasa bamboo (<i>Sasa kurilensis</i>) dominates the forest floor in many fir forests. Study plots with higher sasa coverage had fewer juvenile <i>A. mariesii</i> trees. Sasa coverage tended to increase as altitude increased, and there were no <i>A. mariesii</i> seedlings and saplings in the plots at high altitudes. This tendency was extremely noticeable on the western slope of Mt. Jizoudake, which was also the area in which sections with high mortality rates were most concentrated in this study area. Therefore, mass mortality forests dominated by sasa at high elevations are predicted to be difficult to regenerate because they have few juvenile trees on the forest floor.</p>

Journal

  • Journal of the Japanese Forest Society

    Journal of the Japanese Forest Society 102(2), 108-114, 2020

    THE JAPANESE FORESTRY SOCIETY

Codes

  • NII Article ID (NAID)
    130007850329
  • NII NACSIS-CAT ID (NCID)
    AA12003078
  • Text Lang
    JPN
  • Article Type
    journal article
  • ISSN
    1349-8509
  • NDL Article ID
    030462746
  • NDL Call No.
    Z18-340
  • Data Source
    NDL  J-STAGE  JASI 
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