アカマツ森林内のモノテルペン高度分布 [in Japanese] Profiles of Monoterpene Concentrations in a Japanese Red Pine Forest [in Japanese]
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Monoterpenes are highly reactive biogenic volatile organic compounds (BVOCs) with O<SUB>3</SUB>, OH radical, and NO<SUB>3</SUB> radical. Although these reactions may occur in the aerial space under tree canopies, only a few studies about monoterpene behavior under the canopy are available. In the present study, concentration profiles of six monoterpenes (α-pinene, myrcene, <I>β</I>-pinene, sabinene, limonene and <I>β</I>-phellandrene) were measured in a Japanese red pine forest in June, July and August, 2002. Their concentrations were usually low in the daytime, but high in the nighttime. Monoterpenes were stored under the canopy during nighttime and the amount as a total of the six monoterpenes was calculated as more than 700 nmol m<SUP>-2</SUP>. The variations of their concentration ratios were also observed. The concentration ratio of myrcene to <I>β</I>-pinene was usually low in nighttime and high in daytime. It ranged from 0.27 to 2.28. Correlations between the ratio of myrcene/<I>β</I>-pinene and O<SUB>3</SUB> concentration or NO<SUB>3</SUB> radical production rate were 0.78 or 0.54, respectively. These results suggested the possibility that the low concentration ratio in the nighttime was due to decomposing of monoterpenes during the storage period under the canopy. The stored monoterpenes would influence the next-morning fluxes since these fluxes include stored and decomposed monoterpenes during the nighttime. The evaluation of the amounts of stored and decomposed monoterpenes will be important when measuring monoterpene fluxes or determining monoterpene contributions to aerosol formation in the forests.
Eco-Engineering 19(1), 39-48, 2007-01-31
The Society of Eco-Engineering