Sources of error in estimating stand transpiration using allometric relationships between stem diameter and sapwood area for Cryptomeria japonica and Chamaecyparis obtusa
Sources of error in estimating stand transpiration using allometric relationships between stem diameter and sapwood area for Cryptomeria japonica and Chamaecyparis obtusa
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DOI：
10.1016/j.foreco.2004.10.066
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发表时间：
2005-02
影响因子：
3.7
通讯作者：
T. Kumagai;H. Nagasawa;T. Mabuchi;Shigeru Ohsaki;K. Kubota;Kimio Kogi;Yasuhiro Utsumi;S. Koga;K. Otsuki
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文献类型：
--
作者：
T. Kumagai;H. Nagasawa;T. Mabuchi;Shigeru Ohsaki;K. Kubota;Kimio Kogi;Yasuhiro Utsumi;S. Koga;K. Otsuki
林分边材面积(AS_STAND)的估算是利用树液流通量测定林分蒸腾(E)的最关键因素之一。AS_STANE一般使用林分中所有树木的树干直径(DBH)数据和基于现有异速生长数据描述胸径和边材面积(AS_TREE)之间关系的异速生长方程来估计。为了检验在使用小样本量的异速生长方程时产生的E中的误差，对原始的异速生长数据集使用蒙特卡罗抽样技术。在本研究中，研究林分中的所有树木(921株柳杉和1226株钝顶柳杉)都提供了原始异速生长数据(胸径和AS_TREE)。蒙特卡罗模拟允许得出适当的E估计所需的样本树的数量。结果表明，E估计的潜在误差几乎是稳定的，两种铬的样本量都超过20。Jumonica和中国稻曲霉Ch.钝顶牛。这意味着，在估算两个物种的E时，至少但不超过20棵树是异速生长方程所必需的。
Estimations of stand sapwood area (AS_stand) are among the most critical factors for determining stand transpiration (E) using sap flux measurements. AS_standis generally estimated using stem diameter (DBH) data measured for all trees in a stand and an allometric equation that describes the relationship between DBH and sapwood area (AS_tree) based on available allometric data. To examine the errors in E that are generated when using the allometric equation with a small sample size, the Monte Carlo sampling technique was used with an original allometric data set. In this study, all trees (921 Cryptomeria japonica and 1226 Chamaecyparis obtusa) in the studied stands provided the original allometric data (DBH and AS_tree). Monte Carlo simulations allow the number of sample trees required for an appropriate E estimate to be derived. The results revealed that potential errors in the E estimate were almost stable with a sample size of over 20 for both Cr. japonica and Ch. obtusa. This implies that at least, but not more than, 20 trees are necessary for the allometric equation when estimating E for both species.