Variation in wood density determines spatial patterns in Amazonian forest biomass
Variation in wood density determines spatial patterns in Amazonian forest biomass
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DOI：
10.1111/j.1365-2486.2004.00751.x
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发表时间：
2004-05-01
影响因子：
11.6
通讯作者：
Martínez, RV
中科院分区：
文献类型：
--
作者：
Baker, TR;Phillips, OL;Martínez, RV
生物量估计的不确定性是热带森林碳通量模型的最大限制之一。亚马逊河流域内直径大于10厘米的树木地上生物量（AGB）的实地估计数以前的比较一直受到限制，西部亚马逊森林的数据缺乏，并使用特定地点的方法来估计库存数据的生物量。此外，在林分水平的木材比重的区域变化的作用，以前没有被考虑。使用数据从56个成熟的森林地块在亚马逊河流域，我们认为物种组成（木材比重）和森林结构（断面积）在确定AGB的变化的相对作用。平均林分水平的木材比重，每干的基础上，是15.8%，在中部和东部的森林，亚马逊河流域西北部相比。这种格局是由于亚马逊河中部和东部比重值高的分类群的多样性和丰富性较高，而亚马逊河西部比重值低的分类群的多样性和丰富性较高。对于两个估计的AGB来自使用不同的异速生长方程，断面积解释51.7%和63.4%，和林分级比重45.4%和29.7%，在AGB的总变异。比重的变化是重要的，因为它决定了区域规模，空间格局的AGB。当比重加权包括在内，亚马逊森林中部和东部有显着较高的AGB比在西北或西南亚马逊的立场。因此，物种组成的区域尺度模式定义了整个亚马逊河流域AGB的广泛梯度。
Uncertainty in biomass estimates is one of the greatest limitations to models of carbon flux in tropical forests. Previous comparisons of field-based estimates of the aboveground biomass (AGB) of trees greater than 10 cm diameter within Amazonia have been limited by the paucity of data for western Amazon forests, and the use of site-specific methods to estimate biomass from inventory data. In addition, the role of regional variation in stand-level wood specific gravity has not previously been considered. Using data from 56 mature forest plots across Amazonia, we consider the relative roles of species composition (wood specific gravity) and forest structure (basal area) in determining variation in AGB.Mean stand-level wood specific gravity, on a per stem basis, is 15.8% higher in forests in central and eastern, compared with northwestern Amazonia. This pattern is due to the higher diversity and abundance of taxa with high specific gravity values in central and eastern Amazonia, and the greater diversity and abundance of taxa with low specific gravity values in western Amazonia. For two estimates of AGB derived using different allometric equations, basal area explains 51.7% and 63.4%, and stand-level specific gravity 45.4% and 29.7%, of the total variation in AGB. The variation in specific gravity is important because it determines the regional scale, spatial pattern of AGB. When weighting by specific gravity is included, central and eastern Amazon forests have significantly higher AGB than stands in northwest or southwest Amazonia. The regional-scale pattern of species composition therefore defines a broad gradient of AGB across Amazonia.