Baker Timothy R, Phillips Oliver L, Malhi Yadvinder, Almeida Samuel, Arroyo Luzmila, Di Fiore Anthony, Erwin Terry, Higuchi Niro, Killeen Timothy J, Laurance Susan G, Laurance William F, Lewis Simon L, Monteagudo Abel, Neill David A, Vargas Percy Núñez, Pitman Nigel C A, Silva J Natalino M, Martínez Rodolfo Vásquez
Max-Planck-Institut für Biogeochemie, Postfach 10 01 64, D-07701 Jena, Germany.
Philos Trans R Soc Lond B Biol Sci. 2004 Mar 29;359(1443):353-65. doi: 10.1098/rstb.2003.1422.
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) m2), 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.
菲利普斯等人之前对亚马逊森林永久样地生物量变化的一项研究被用于推断区域碳汇的存在。然而，这些结果引发了关于采样和方法问题的激烈争论。因此，我们使用更新的清查数据对老龄亚马逊森林样地的生物量变化进行了新的分析。我们发现，在59个样地中，自样地设立以来，直径超过10厘米的树木地上干生物量（AGB）以每年每公顷1.22±0.43 公吨（ha⁻¹ yr⁻¹，其中1公顷 = 10⁴ 平方米）的速度增加，或者如果根据监测的公顷年数对各个样地的值进行加权，则为0.98±0.38 Mg ha⁻¹ yr⁻¹。这一显著增加既不受木材比重的空间或时间变化的干扰，也不依赖于用于估算AGB的异速生长方程。该结论对于有问题树木直径测量的不确定性也很稳健：对于亚马逊西部森林的34个样地，即使对所有使用光学方法进行直径测量和/或在野外工作后需要估算生长率的树木都采用零生长的保守假设，也发现AGB有显著增加。总体而言，我们的结果表明净林分水平变化率略高于菲利普斯等人报告的结果。考虑到采样的空间和时间尺度以及相关研究表明森林生长和茎周转增加，此处呈现的结果表明这些样地的总生物量平均有所增加，并且在过去二十年中老龄亚马逊森林存在区域尺度的碳汇。
