Evaluation of the variation of wood properties with age based on physics

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K05709
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 40020:Wood science-related
• Research Institution: Tottori University
• Principal Investigator: Fujimoto Takaaki 鳥取大学, 農学部, 准教授 (40446331)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: wood variation / Dyson's Brownian motion / Fokker-Planck equation / Statistical mechanics / Helmholtz free energy / Entropy / Irreversible process

Outline of Final Research Achievements

A correct understanding of the variation in wood properties with tree age is of great importance for both the forestry and timber industries. In this study, we evaluated the variation of multiple traits inclusively based on the distribution of eigenvalues calculated from the near-infrared spectral matrix at each cambial age. The eigenvalues diffused with age in any species, such as in Dyson's Brownian motion. The gradual increase in the first eigenvalue indicates that trees form a more ordered wood with age. The age dependency of Shannon entropy and density matrix provided us with knowledge from the perspective of randomness; namely, tree aging from the perspective of the variation of wood properties was clearly an irreversible process. This result offers an important clue for sustainable forest management and the use of wood resources. The proposed method does not depend on a specific coordinate; thus, it will work well using data other than the near infrared spectrum.

Free Research Field

森林圏科学

Academic Significance and Societal Importance of the Research Achievements

木材性質の樹齢依存性，すなわち，樹幹内変動に関する知見は，木材を利用する際はもちろん，適切な森林管理を進める上でも重要である．森林施業の長伐期化，大径材の有効利用など，近年顕在化している林業・木材産業の諸問題と密接に関係している．樹木は加齢にともないより秩序だった木部を形成すること，そしてその過程は非可逆的であるという事実は，持続可能な森林経営と木材資源の有効利用に重要な示唆を与える．本研究の結果で提案した手法は特定の座標系に依存しないため，樹木の加齢現象における木材状態変化の普遍的な振る舞いを見出すことができる．