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No.17 (1970/12) >

Title :地スギ材の年輪巾, 晩材率, 気乾比重, 仮道管長について(沖縄産スギ材の材質(第 1 報))(林学科)
Title alternative :On the annual ring breadth, late wood percentage, specific gravity in air dry and length of tracheid of Ji-sugi (Okinawan name) (Studies on the quality of Sugi wood (Cryptomeria japonica D. Don) grown in Okinawa. I) (Department of Forestry)
Authors :仲宗根, 平男
Authors alternative :Nakasone, Hirao
Issue Date :1-Dec-1970
Abstract :亜熱帯地域に属する沖縄に300年前よりさし木法によって受け継がれたといわれる, いわゆる地スギが北部山奥へ小面積ながら残っている。その地スギ3本を採取し, その幹材の理学的性質を明らかにすることにより, 造林樹種として, 価値判定の資料に役立てる目的でこの実験を行なった。なお福岡産のスギ1本も実験に加えた。測定結果は下記の通りであった。1)年輪巾 : 地スギ材は未成熟材部で変動が大きく, 成熟材部で安定している。2)晩材率 : 晩材率が70%を示し, 本土産スギ材10∿25%と比較すると著しく高い値を示している。3)気乾比重 : 早材は地スギ材0.3∿0.5,福岡産スギ材0.2∿0.3で地スギ材が高く, 晩材は0.7∿0.9と産地による差がない。4)細胞膜厚 : 早材で6∿12μ, 晩材6∿14μと産地による差はない。5)細胞径 : 早材は地スギ材20∿40μ, 福岡産スギ材40∿50μと福岡産スギ材が大きい。6)細胞径に対する細胞膜厚割合 : 早材は地スギ材が20∿40%, 福岡産スギ材10∿20%と地スギ材が高く, 晩材は地スギ材50∿80%, 福岡産スギ材50∿70%で両者に差はない。この高い値は明らかに早材と区別される。7)仮道管長 : 地スギ材の未成熟材は髄から10番目年輪程度までで, 成熟期に達する期間は福岡産スギ材と大差ないが, 仮道管長は短かい傾向がある。8)地スギ材の特徴 : 晩材率が70%と著しく高く, 早材細胞径も小さく, したがって比重の高い緻密な材である。
Ji-sugi (Cryptomeria japonica D. Don) which has been saying to inherited planting by slip since 300 years in subtropic Ryukyu islands grow on small area in northern part of Okinawa. In the present work, the materials of ji-sugi were collected three wood and Japanese material was harvested a piece of wood in Fukuoka area. The structural character of each wood for experiment on valuable determination as planting species was studied. The results obtained are summarized as follows : 1) Annual ring breadth : The ji-sugi shown a great variation in part of juvenile wood and was regularly in part of mature wood. 2) Late wood percentage : late wood percentage of was 70% in the ji-sugi and 10∿25% in the Japanese area sugi. 3) Specific gravity in air dry : Early wood of the ji-sugi had 0.3∿0.5 and early wood of the Fukuoka areas sugi had 0.2∿0.3. But late wood of the both sugis (The ji-sugi and the Fukuoka areas sugi) had the same value (0.7∿0.9). 4) Thickness of double cell wall : Early wood and late wood of both the sugi were 6∿12μ and 6∿14μ respectively. 5) Cell diameter : Early wood of the ji-sugi shown lower value of 20∿40μ than the Fukuoka area sugi of 30∿60μ. 6) Rate of wall thickness against cell diameter : Early wood of the ji-sugis shown higher value 20∿40% than the Fukuokas sugi of 10∿20%. Late wood of both the sugis had the same value. The value is distinguished from early wood. 7) Length of tracheid : Juvenile wood of the ji-sugi was from pith to the 10th annual ring and period got to mature age was the same Japanese sugi. But length of tracheid was short. 8) Character of the ji-sugi : Late wood percentage of late wood shown a high value (70%). Cell diameter of early wood was short. Therefore, the ji-sugi have a great specific gravity in air dry and is minute wood. On the detailed character of wood, experiment, have been proceeding.
Type Local :紀要論文
ISSN :0370-4246
Publisher :琉球大学農学部
URI :http://hdl.handle.net/20.500.12000/4514
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.17 p.192 -202
Appears in Collections:No.17 (1970/12)

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