著者

NEGISI Ken'itiroo

出版者

東京大学大学院農学生命科学研究科附属演習林

雑誌

東京大学農学部演習林報告 (ISSN:03716007)

巻号頁・発行日

vol.66, pp.209-222, 1974

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アカマツ林の呼吸消費量を推定する基礎資料のひとつとして,10数年生のアカマツの幹と枝の呼吸量をしらべた。幹または枝を年ごとに15~40cmのながさの丸太にきり,23℃の呼吸室にいれ,CO2をのぞいた空気を300~1,200cc/分の流量でおくり,でてくるCO2を赤外線分析器で定量して呼吸量とした。外気温と呼吸室温の差がおおきいばあいは,呼吸量が一定になるのにかなりの時間を必要とするが(Fig. 1),日がたつにつれ,いわゆる傷害による呼吸上昇がめだってくるので(Table 1),各試料木についての測定は伐倒後24時間以内におえた。The respiration rates on a weight basis decrease with increasing diameter both in stem and in branch sections detached from young pine trees, while those on a surface area of outer bark basis do not change in stem sections and increase somewhat in branch ones. Relations between respiration rate (Rs) and diameter (D) are approximately linear on the log-log coordinates and expressed as a simple equation, log Rs=b log D+a respectively. But the individual values show a relatively wide variation probably caused by the difference in rate of diameter growth in sample sections. The respiration rates per unit dimension in dominant trees are higher than in suppressed ones, in other words, the younger the sample, the higher the rates become among the stem or branch sections of the same diameter. And an application of the Rs-D relation will result in an erroneous estimate of the respiratory losses of a stand, unless the differences in growth rate or age are considered.