Increasing biomass in Amazonian forest plots
Increasing biomass in Amazonian forest plots
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DOI：
10.1098/rstb.2003.1422
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发表时间：
2004-03-29
影响因子：
6.3
通讯作者：
Martínez, RV
中科院分区：
文献类型：
--
作者：
Baker, TR;Phillips, OL;Martínez, RV
菲利普斯等人先前对亚马逊森林永久样地生物量变化的研究被用来推断区域碳汇的存在。然而，这些结果引起了关于抽样和方法问题的激烈辩论。因此，我们提出了一个新的分析生物量的变化，在古老的亚马逊森林地块使用更新的库存数据。我们发现，在59个站点中，直径超过10 cm的树木（AGB）的地上干生物量自小区建立以来每年每公顷增加1.22 +/- 0.43 Mg（ha（-1）yr（-1），其中1 ha = 10（4）m（2）），或0.98 +/- 0.38 Mg ha（-1）yr（-1），如果用监测的公顷年数加权单个地块值。这种显着的增加既不混淆木材比重的空间或时间变化，也不依赖于异速生长方程用于估计AGB。该结论对于问题树木直径测量的不确定性也具有鲁棒性：对于亚马逊西部森林的34块地块，即使保守假设所有树木的直径测量均为零增长，也发现AGB显着增加，其中使用光学方法和/或生长率进行测量需要在实地工作后估计。总的来说，我们的研究结果表明，净林分水平变化率略高于菲利普斯等人的报告。考虑到空间和时间尺度的采样和相关研究表明，森林生长和树干周转率增加，这里提出的结果表明，这些地块的总生物量平均增加，并且在旧的-在过去的二十年里，亚马逊森林的增长。
A previous study by Phillips et al. of changes in the biomass of permanent sample plots in Amazonian forests was used to infer the presence of a regional carbon sink. However, these results generated a vigorous debate about sampling and methodological issues. Therefore we present a new analysis of biomass change in old-growth Amazonian forest plots using updated inventory data. We find that across 59 sites, the above-ground dry biomass in trees that are more than 10 cm in diameter (AGB) has increased since plot establishment by 1.22 +/- 0.43 Mg per hectare per year (ha(-1) yr(-1), where 1 ha = 10(4) m(2)), or 0.98 +/- 0.38 Mg ha(-1) yr(-1) if individual plot values are weighted by the number of hectare years of monitoring. This significant increase is neither confounded by spatial or temporal variation in wood specific gravity, nor dependent on the allometric equation used to estimate AGB. The conclusion is also robust to uncertainty about diameter measurements for problematic trees: for 34 plots in western Amazon forests a significant increase in AGB is found even with a conservative assumption of zero growth for all trees where diameter measurements were made using optical methods and/or growth rates needed to be estimated following fieldwork. Overall, our results suggest a slightly greater rate of net stand-level change than was reported by Phillips et al. Considering the spatial and temporal scale of sampling and associated studies showing increases in forest growth and stem turnover, the results presented here suggest that the total biomass of these plots has on average increased and that there has been a regional-scale carbon sink in old-growth Amazonian forests during the previous two decades.