2013 Fiscal Year Final Research Report
Effects of insect defoliation and radial growth on decline of Betula maximowicziana
| Project/Area Number |
23580214
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Forest science
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| Research Institution | Hokkaido Research Organization |
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Principal Investigator |
OHNO YASUYUKI 地方独立行政法人北海道立総合研究機構, 森林研究本部林業試験場, 主査 (30414246)
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| Co-Investigator(Kenkyū-buntansha) |
WATANABE Yoko 北海道大学, 北方生物圏フィールド科学センター, 学術研究員 (30532452)
MATSUKI Sawako 岩手大学, 農学部, 講師 (40443981)
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| Co-Investigator(Renkei-kenkyūsha) |
TAKIYA Mika 北海道立総合研究機構, 林業試験場, 研究主任 (80414259)
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| Project Period (FY) |
2011 – 2013
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| Keywords | 樹木衰退 / 食葉性昆虫 / 肥大成長 / 二次展葉 / 死亡 |
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| Research Abstract |
To clarify a decline process of Betula maximowicziana Regel in a secondary forest after the outbreaks of herbivorous insects (larvae of Caligula japonica), we selected 46 trees for the observation and investigated the annual variation in degree of insect defoliation and crown condition, and radial growth before the outbreaks. Severe crown dieback (i.e. decline) occurred in 15% of the observed tree in the year following the outbreak of the three consecutive years. Generalized liner model revealed that the severe crown dieback is likely to occur with increasing degree of defoliation and with decreasing the radial growth rate before the outbreaks. Then, 80% of the severe decline trees died within two years. These results indicate that B. maximowicziana that have a long-lasting low growth rate would be susceptible to severe insect defoliation.
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