Explore the radial growth period of trees: Do tree ring formation complete annually?

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K19228
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 40:Forestry and forest products science, applied aquatic science, and related fields
• Research Institution: Shinshu University
• Principal Investigator: Yasue Koh 信州大学, 学術研究院農学系, 准教授 (00324236)
• Co-Investigator(Kenkyū-buntansha): 半 智史 東京農工大学, (連合)農学研究科(研究院), 准教授 (40627709) ; 高嶋 敦史 琉球大学, 農学部, 助教 (40433099)
• Project Period (FY): 2018-06-29 – 2021-03-31
• Keywords: 年輪 / 形成層 / フェノロジー / 肥大成長 / ラベリング / 13C

Outline of Final Research Achievements

We examined "Is the formation of annual rings completed within a year?" using various tree species growing in various environments.
As a result of microscopic observation of developing xylems, the survival of several tracheids of Pinus pumila and Cryptomeria japonica after the cessation of cambium activity or overing winter. Although, deposition of cell walls in spring was not confirmed since the exitance of S3 layer. As a result of 13CO2 pulse labeling before the start of cambium activity, the use of photosynthetic products in the spring of current year existed in the outermost part of the annual ring of the previous year in Chamaecyparis obtusa, C. japonica and Quercus myrsinifolia. As a result of observation with Nano-SIMS for C. obtusa, 13C was used for wall thickening of ray parenchyma that cross the annual ring boundary.

Free Research Field

年輪年代学

Academic Significance and Societal Importance of the Research Achievements

少なくとも，樹種によっては前年年輪にまたがって存在する放射柔細胞の壁肥厚に当年形成層活動開始前の光合成産物が使われていることが確認された。樹木成長に対する気候変動の影響評価や気候復元を行う上で重要な手法である年輪年代学的研究に対して「炭素・酸素同位体比，年輪内最大密度を指標とする研究においては，形成層活動終了後の気候情報が年輪に含まれうることを考慮する必要がある」ことを提言する。