論文

査読有り
2013年5月

Azimuthal and radial variations in sap flux density and effects on stand-scale transpiration estimates in a Japanese cedar forest

TREE PHYSIOLOGY
  • Yoshinori Shinohara
  • ,
  • Kenji Tsuruta
  • ,
  • Akira Ogura
  • ,
  • Fumikazu Noto
  • ,
  • Hikaru Komatsu
  • ,
  • Kyoichi Otsuki
  • ,
  • Toshisuke Maruyama

33
5
開始ページ
550
終了ページ
558
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1093/treephys/tpt029
出版者・発行元
OXFORD UNIV PRESS

Understanding radial and azimuthal variation, and tree-to-tree variation, in sap flux density (F-d) as sources of uncertainty is important for estimating transpiration using sap flow techniques. In a Japanese cedar (Cryptomeria japonica D. Don.) forest, F-d was measured at several depths and aspects for 18 trees, using heat dissipation (Granier-type) sensors. We observed considerable azimuthal variation in F-d. The coefficient of variation (CV) calculated from F-d at a depth of 0-20 mm (F-d1) and F-d at a depth of 20-40 mm (F-d2) ranged from 6.7 to 37.6% (mean = 28.3%) and from 19.6 to 62.5% (mean = 34.6%) for the -azimuthal directions. F-d at the north aspect averaged for nine trees, for which azimuthal measurements were made, was -obviously smaller than F-d at the other three aspects (i.e., west, south and east) averaged for the nine trees. F-d1 averaged for the nine trees was significantly larger than F-d2 averaged for the nine trees. The error for stand-scale transpiration (E) estimates caused by ignoring the azimuthal variation was larger than that caused by ignoring the radial variation. The error caused by ignoring tree-to-tree variation was larger than that caused by ignoring both radial and azimuthal variations. Thus, tree-to-tree variation in F-d would be more important than both radial and azimuthal variations in F-d for E estimation. However, F-d for each tree should not be measured at a consistent aspect but should be measured at various aspects to make accurate E estimates and to avoid a risk of error caused by the relationship of F-d to aspect.

Web of Science ® 被引用回数 : 35

リンク情報
DOI
https://doi.org/10.1093/treephys/tpt029
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000319430900010&DestApp=WOS_CPL

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