On linking multiyear biometric measurements of tree growth with eddy covariance‐based net ecosystem production
On linking multiyear biometric measurements of tree growth with eddy covariance‐based net ecosystem production
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DOI：
10.1111/j.1365-2486.2008.01800.x
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发表时间：
2009-04
影响因子：
11.6
通讯作者：
T. Ohtsuka;N. Saigusa;H. Koizumi
中科院分区：
文献类型：
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作者：
T. Ohtsuka;N. Saigusa;H. Koizumi
树木的直径生长和凋落物的年度测量开始于1998年，使用1.0公顷的永久地块下的通量塔在高山通量网站，日本中部。这为比较树木生长的年际变化与基于涡动协方差的净生态系统生产（NEP）的研究提供了机会。研究了基于生物特征的多年净初级生产力（NPP）和基于涡度协方差的NEP之间的可能联系，以确定自养生产和异养呼吸（HR）对落叶林生态系统NEP年际变化的贡献。我们还将NEP* 定义为在土壤呼吸（SR）测量期间储存在生态系统中的可测量有机物质。在给定年份内，基于生物特征的NEP* 与基于涡度协方差的NEP的差异在55%和105%之间变化。在8年的研究期间（1999-2006年），木质组织NPP（茎和粗根）在0.88 - 1.96 Mg C ha−1 yr−1之间变化显著。年木质组织NPP与基于涡度协方差的NEP呈正相关（r2=0.52，P<0.05）。然而，叶NPP（r2=0.03）和HR（r2=0.06）与涡度协方差NEP均不相关。因此，有人推测，生态系统碳交换的年际变化是直接负责的自养生产，特别是在生态系统的木本成分的碳积累的年际变化。此外，基于生物特征的NEP* 和基于涡度协方差的NEP的年际变化相似，SR和树叶NPP的变化较小，表明高山站非生物池中碳的净积累恒定。
Annual measurements of the diameter growth and litter fall of trees began in 1998 using a 1.0 ha permanent plot beneath a flux tower at the Takayama flux site, central Japan. This opened up an opportunity for studies that compare the interannual variability in tree growth with eddy covariance‐based net ecosystem production (NEP). A possible link between multiyear biometric‐based net primary production (NPP) and eddy covariance‐based NEP was investigated to determine the contribution of autotrophic production and heterotrophic respiration (HR) to the interannual variability of NEP in deciduous forest ecosystems. We also defined the NEP* as the measurable organic matter stored in an ecosystem during the interval in which soil respiration (SR) measurements were taken. The difference of biometric‐based NEP* from eddy covariance‐based NEP within a given year varied between 55% and 105%. Woody tissue NPP (stems and coarse roots) varied markedly from 0.88 to 1.96 Mg C ha−1 yr−1 during the 8‐year study period (1999–2006). Annual woody tissue NPP was positively correlated with eddy covariance‐based NEP (r2=0.52, P<0.05). However, neither foliage NPP (r2=0.03) nor HR (r2=0.06) were correlated with eddy covariance‐based NEP. Therefore, it was hypothesized that interannual variability in the ecosystem carbon exchange was directly responsible for much of the interannual variation in autotrophic production, especially carbon accumulation in the woody components of the ecosystem. Moreover, similar interannual variations of biometric‐based NEP* and eddy covariance‐based NEP with small variations in SR and foliage NPP suggest a constant net accumulation of carbon in nonliving pools at the Takayama site.