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The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus >
No.38 (1991/12) >

Title :第 5 報 除伐後の林分構造及び樹下植栽イスノキの活着率と成長について(天然生常緑広葉樹林の林相改善に関する研究)(附属演習林)
Title alternative :Stand structure after cutting and survival rate and growth of underplanting Distylium racemosum (Studies on improvement of stand structure of evergreen broadleaved forest in Okinawa (5)) (Forestry Experiment Station)
Authors :平田, 永二
安里, 練雄
寺園, 隆一
生沢, 均
Authors alternative :Hirata, Eiji
Asato, Isao
Terazono, Ryuichi
Ikuzawa, Hitoshi
Issue Date :4-Dec-1991
Abstract :天然生林の成長の促進及び形質の改善を目的として除伐を実行し,その後樹種構成の改善を図るため,イスノキの樹下植栽を行った。本報では,除伐後の林分構造とイスノキの活着率及び植栽後約1年間の伸長成長について明らかにした。除伐によって平均直径が10∿36%,平均樹高が6∿16%増大し,樹種の構成も目的樹種がかなり増加した。除伐前後の樹高及び胸高直径の順位曲線に対して,2階差分方程式を当てはめた結果,樹高は対称型,胸高直径は非対称型の曲線式が良く適合し,除伐後の順位曲線は,除伐前に比べいずれも右さがりとなり,低順位の個体が多く除伐されたことを示している。イスノキの活着率は,植栽後約1年5ヶ月目でも平均約98%となり,極めて高い数値を示している。1年間の伸長成長は除伐の程度によって差が認められ,除伐率が高いほど良好で,除伐をしなかった対照区(プロット1)では先枯れのため負の値を示した。
Improvement cutting for the purpose of enhancing the growth of a naturally regenerated forest and the improvement of its quality was carried out and, later, in order to improve species composition, underplanting of Distylium rasemosum was carried out. In this report, the stand structure observed after improvement cutting and the survival rate and elongation growth for 1 year after planting Distylium rasemosumr were explained. Improvement cutting gave a 10∿36% increase in mean diameter, a 6∿16% increase in mean height and an increase in economic species within species composition. As a result of fitting a difference equation of second order to a decreasing order curve of the tree height and breast height diameter observed just before and after improvement cutting, a better fitting was observed as a symmetric curve equation for height and an asymmetric curve equation for breast height diameter and a decreasing order curve after improvement cutting gave a curve with lower values at the right hand side in comparision to that observed before improvement cutting in all cases studied, indicating that large number of relatively low order trees were cut. Survival rate of Distylium rasemosum was about 98% in average even in 1 year and 5 months after planting. Elongation growth in 1 year significantly varied according to the extent of improvement cutting : a greater extent of improvement cutting resulted in a better elongation growth. The reference plots without improvement cutting gave negative values due to tree-top witherring.
Type Local :紀要論文
ISSN :0370-4246
Publisher :琉球大学農学部
URI :http://hdl.handle.net/20.500.12000/3849
Citation :琉球大学農学部学術報告 = The Science Bulletin of the Faculty of Agriculture. University of the Ryukyus no.38 p.289 -296
Appears in Collections:No.38 (1991/12)

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