Growth and mortality of a main tree species after disturbance in Japanese northern forest: Effect of competition as a long-lasting stress

2016 Fiscal Year Final Research Report

• Project/Area Number: 26450205
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Forest science
• Research Institution: Hokkaido Research Organization
• 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)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 肥大成長 / 年輪幅指数 / 個体間競争 / 食葉性昆虫 / 素因 / 死亡 / ウダイカンバ

Outline of Final Research Achievements

To clarify mortality pattern of Betula maximowicziana Regel （monarch birch） after the outbreak of herbivores insects in 2011, we analyzed the individual diameter growth (GD) in the period prior to the outbreak and the subsequent mortality (2012-2014). Individual GD were affected by the competition from neighbors and initial tree size: GD decreased with increasing asymmetric competition from Quercus crispula Blume (mizu oak) and with decreasing initial size. The growth reduction of monarch birch was imposed by asymmetrical competition from larger mizu oak, indicating that larger mizu oak might cause a reduction of light resources to monarch birch. During the three-year period after the outbreak, 17% of the observed trees died. Logistic regression analysis revealed that mortality rate increased with decreasing GD. These results suggest that the competition was an underlying stress factor that reduced the growth and raised the mortality after the outbreak.

Free Research Field

農学