Strong and stable relationships between tree-ring parameters and forest-level carbon fluxes in a Siberian larch forest
Strong and stable relationships between tree-ring parameters and forest-level carbon fluxes in a Siberian larch forest
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DOI：
10.1016/j.polar.2019.02.001
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发表时间：
2019-09
期刊：
影响因子：
1.8
通讯作者：
S. Tei;A. Sugimoto;A. Kotani;T. Ohta;Tomoki Morozumi;Soma Saito;Shuhei Hashiguchi;T. Maximov
中科院分区：
文献类型：
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作者：
S. Tei;A. Sugimoto;A. Kotani;T. Ohta;Tomoki Morozumi;Soma Saito;Shuhei Hashiguchi;T. Maximov
树轮宽度指数和卫星得出的植被指数，如归一化植被指数，被用作过去森林碳吸收的长期指标。然而，关于RWI和NDVI在生态系统一级代表什么，仍然存在根本问题。为了解决这个问题，我们比较了树轮参数（RWI和碳同位素比：δ 13 C）和NDVI产品与森林生态系统CO2通量估计使用涡度协方差法，在西伯利亚东部的落叶松林。2004-2014年，RWI和树轮δ 13 C与生态系统总初级生产力（GPP）相关性较好，时间稳定性较高。然而，NDVI产品并没有表现出任何时间稳定的关系与全球生产力。这可能归因于该森林中林下植被的显著变化，即，从密集的越橘到灌木和耐湿的草，因为2007-2008年的环境过于潮湿。林下植被的变化可以通过NDVI产品反映，但不能通过GPP反映。我们的研究结果表明，这是更可行的研究森林碳吸收使用树木年轮参数比使用卫星派生的植被指数在这样的落叶松为主的森林生态系统在西伯利亚东部。
The tree-ring width index (RWI) and satellite-derived vegetation indices, such as the Normalized Difference Vegetation Index (NDVI), are used as long-term indicators of the past forest carbon uptake. However, fundamental questions remain with respect to what is represented by the RWI and NDVI at the ecosystem level. To address this question, we compared tree-ring parameters (RWI and the carbon isotope ratio: δ13C) and NDVI products with forest ecosystem CO2fluxes estimated using the eddy covariance method, at a larch forest in eastern Siberia. The RWI and tree-ring δ13C correlated well with the ecosystem gross primary production (GPP), and their temporal stabilities were high during 2004–2014. However, the NDVI products did not show any temporally stable relationship with the GPP. This could be ascribed to significant changes in the understory vegetation in this forest, i.e., from dense cowberry to shrubs and moisture-tolerant grasses, because of an excessively moist environment during 2007–2008. Changes in the understory vegetation could be reflected by the NDVI products but not by the GPP. Our results indicate that it is more feasible to study forest carbon uptake using tree-ring parameters than using satellite-derived vegetation indices in such larch-dominated forest ecosystems in eastern Siberia.