Elucidation of the mechanism of an unfruitful phenomenon in Pacific-type beech trees

2023 Fiscal Year Final Research Report

• Project/Area Number: 20H03032
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 40010:Forest science-related
• Research Institution: Kochi University
• Principal Investigator: Ichie Tomoaki 高知大学, 教育研究部自然科学系農学部門, 教授 (80403872)
• Co-Investigator(Kenkyū-buntansha): 上谷 浩一 愛媛大学, 農学研究科, 教授 (80638792)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 太平洋型ブナ / 結実豊凶 / 温暖化 / 不稔 / 林冠 / 遺伝的多様性

Outline of Final Research Achievements

In this study, we focused on the unfruitful phenomenon of Pacific-type beech (Fagus crenata) distributed over the Pacific side of Japan, and aimed to understand the current status and mechanism of this phenomenon. Although the Pacific-type beech has genetically distinct populations from those of the Sea of Japan-type beech, inbreeding depression due to reduced genetic diversity has not occurred in it, and male flower fertility was observed. On the other hand, beech trees in the Ogawa Forest Reserve (Ibaraki) have remained nearly unfruitful for more than 10 years, and the seed setting rate in the beech canopy was extremely low. High rates were shown when flowering branches were covered with mesh bags, suggesting that some external enemy may be impairing the fertilization of the beech. In order to sustainably protect the Pacific-type beech, it is necessary to clarify the existence of this enemy and take countermeasures against it.

Free Research Field

樹木生理生態学

Academic Significance and Societal Importance of the Research Achievements

生態系の重要樹種であるにもかかわらず、長寿命かつ種子生産に豊凶性を持つために、これまで問題の深刻さに誰も気づいていなかった太平洋ブナの不稔現象について、その現状やメカニズムを遺伝・生理生態・生物間相互作用の観点から定量的に解明した世界初の研究である。太平洋型ブナの結実に影響を与える外敵の特定には至っていないものの、開花枝をネット等で覆うことで高い結実率を実現することを明らかにした。具体的なブナ個体群の保全方法を提示できたことは、社会的な課題である持続的な開発目標(SDGs）への貢献にもつながる。