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仲谷 朗 (ナカヤ アキラ)
| 北方生物圏フィールド科学センター 森林圏ステーション 北管理部 | 博士研究員 |
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■ 論文- Figured wood occurrence in Acer pictum is related to tree form
Akira Nakaya; Toru Miyazaki; Toshiya Yoshida
Canadian Journal of Forest Research, 56, 1, 9, Canadian Science Publishing, 2026年01月23日, ［査読有り］, ［筆頭著者］
英語, 研究論文（学術雑誌）, Figured wood in Acer pictum is valued for furniture and musical instruments, yet its occurrence remains poorly understood because reliable assessment is difficult without felling trees. This study examined the relationship between the occurrence of figured wood (wavy and birdseye) and tree characteristics in 60 A. pictum trees within a 16.8 ha natural forest in northern Japan. Boards 30 cm in length were obtained from logs cut 3 m above ground, and the proportion of figured wood (PFW) was quantified. Structural equation modeling (SEM) was used to evaluate direct and indirect effects of stem crookedness (SC), fork height (FH), annual ring width (ARW), and basal area on PFW. Although 87% of trees exhibited figure, the mean PFW was low (7.0%, SD = 9.8%), and only 5% of trees showing PFW greater than 31%. Contrary to expectations that larger trees produce more figure, PFW decreased from pith to bark. SEM indicated that SC and FH were the strongest predictors of PFW, whereas ARW showed no significant effect. These results suggest that silvicultural interventions, such as thinning, may influence figure formation primarily through alterations to stem form rather than growth rate. We argue that retaining atypical tree form may improve the future commercial value of hardwood forests. - Growth characteristics of standing individual Japanese oak (Quercus crispula) qualifying for barrel timber in a secondary forest
Akira Nakaya; Satoru Murakami; Hisashi Ohsaki; Yasuyuki Ohno; Toshiya Yoshida
Forest Ecology and Management, 598, 123183, 123183, Elsevier BV, 2025年12月15日, ［査読有り］, ［筆頭著者］
英語, 研究論文（学術雑誌） - 色指標に基づくサポートベクトルマシンによるダケカンバ心材の腐朽検出
村上了; 大崎久司; 仲谷朗; 吉田俊也
木材工業, 80, 10, 378, 383, 2025年10月01日, ［査読有り］
日本語, 研究論文（学術雑誌） - Tree and stand characteristics associated with the occurrence of false heartwood in individual Japanese white birch trees
Akira Nakaya; Hisashi Osaki; Yasuyuki Ohno; Toshiya Yoshida
Canadian Journal of Forest Research, 54, 5, 601, 610, Canadian Science Publishing, 2024年04月05日, ［査読有り］, ［筆頭著者］
英語, 研究論文（学術雑誌）, New wood uses of Japanese white birch ( Betula platyphylla var. japonica) have attracted much attention in recent years, but false heartwood has led to a decline in commercial value due to its irregular wood color. In this study, we assessed the occurrence of false heartwood and its proportion to stem cross-sectional area (PFH) in individual Japanese white birch (482 trees) in a ca. 70-year-old natural secondary forest. Specifically, we investigated the relative strength of the direct/indirect effects of individual size (BA), growth rate (GR), crown ratio (CR), number of branch scars (NBS), basal area sum of neighboring trees (BAS) and topographic wetness index (TWI) on PFH. In total, 80.3% of trees had false heartwood. CR was found to be the most important factor, acting through direct and indirect negative effects. BA and NBS had a positive effect, and TWI had a negative effect on PFH. BA had a positive correlation with tree age, indicating that PFH can be reduced in trees with faster growth. Simultaneously, BAS had an indirect positive effect on PFH. These results suggested that thinning, which reduces BAS and increases CR, can reduce false heartwood.
