2026-03-06T21:31:52Z https://iwate-u.repo.nii.ac.jp/oai

oai:iwate-u.repo.nii.ac.jp:00009021 2023-05-16T11:18:30Z 1504:1506

粗放的に管理されたスギ若齢人工林の簡便な密度管理指標の探索 Selecting a convenient index of stand density for the management of dense plantations of young Sugi (Cryptomeria japonica D. Don) 國崎, 貴嗣 本研究では，岩手県におけるスギ若齢人工林を対象に，無間伐試験地の長期観測データを活用して，過密な人工林の込み具合を適確に評価する，簡便な密度管理指標を検討した。密度管理指標として相対幹距，収量比数，林分形状比，林分胸高断面積，SDIの5つを検討対象とした。散布図の重ね合わせと枯死発生の暫定基準の検討結果から，相対幹距が最良の密度管理指標と考えられる。相対幹距15%前後で自己間引きが生じる段階に達するため，込み過ぎの基準を16%未満とみなすのが適当と考えられる。 This study examined indices correlated with the degree of crowding in young Sugi (Cryptomeria japonica D. Don) plantations and proposed a convenient index of stand　density for the management of overcrowded Sugi plantations. Annual data from tree　censuses spanning 15 years were used, beginning when the Sugi stands were 12 years　old. The analysis included the relative spacing index, a yield index based on the stand　density control diagram, the ratio of mean height to mean diameter, basal stand area, and a stand density index based on the Reineke equation. The analysis of the degree of crowding and onset of tree mortality revealed that the relative spacing index was the best of the five measures. The maintenance of young Sugi stands with a relative spacing index ≥16% effectively prevents self-thinning mortality. 岩手大学農学部附属寒冷フィールドサイエンス教育研究センター 2013-06-01 jpn departmental bulletin paper VoR https://iwate-u.repo.nii.ac.jp/records/9021 0286-4339 岩手大学農学部演習林報告 44 1 18 https://iwate-u.repo.nii.ac.jp/record/9021/files/biuf-n44p1-18.pdf application/pdf 1.8 MB 2016-11-14