Dead Wood Necromass in a Moist Tropical Forest: Stocks, Fluxes, and Spatiotemporal Variability
Dead Wood Necromass in a Moist Tropical Forest: Stocks, Fluxes, and Spatiotemporal Variability
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DOI：
10.1007/s10021-019-00341-5
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发表时间：
2019-09-01
期刊：
影响因子：
3.7
通讯作者：
Muller-Landau, Helene C.
中科院分区：
文献类型：
--
作者：
Gora, Evan M.;Kneale, Riley C.;Muller-Landau, Helene C.
木质残体（WD）储量和通量是森林碳收支的重要组成部分，但仍然研究不足，特别是在热带森林。在这里，我们提出了最全面的评估WD股票和通量尚未在热带森林中进行，包括第一个热带估计悬浮WD。我们依靠在巴拿马古老潮湿热带森林中收集的8年多的数据来量化时空变异性并估计不同成分的最小样本量。下降的WD构成了大部分的WD总质量（78%），站立WD贡献了相当大的少数（21%），悬浮WD是最小的组成部分（1%）。然而，当考虑部分下降的WD高于土壤，大多数WD输入和大约50%的WD股票断开从森林地面。枝倒和藤本植物木材占17%和2%，分别下降的WD。滞留时间平均为1.9年的常设粗WD（CWD; > 20厘米直径）和3.6年的下降CWD。WD库存和输入是高度空间可变的，这样的采样工作，估计在10%的真实值，95%的置信度是必要的，> 130公里的样带下降的CWD和> 550公顷的面积为常设CWD。绝大多数研究涉及低得多的采样工作，这表明，需要更多的数据来精确量化热带森林WD池和通量。在我们的研究中，WD升高的重要性表明需要了解地面以上的海拔如何改变分解速率，并将这种理解纳入森林碳循环模型。
Woody debris (WD) stocks and fluxes are important components of forest carbon budgets and yet remain understudied, particularly in tropical forests. Here we present the most comprehensive assessment of WD stocks and fluxes yet conducted in a tropical forest, including one of the first tropical estimates of suspended WD. We rely on data collected over 8 years in an old-growth moist tropical forest in Panama to quantify spatiotemporal variability and estimate minimum sample sizes for different components. Downed WD constituted the majority of total WD mass (78%), standing WD contributed a substantial minority (21%), and suspended WD was the smallest component (1%). However, when considering sections of downed WD that are elevated above the soil, the majority of WD inputs and approximately 50% of WD stocks were disconnected from the forest floor. Branchfall and liana wood accounted for 17 and 2% of downed WD, respectively. Residence times averaged 1.9 years for standing coarse WD (CWD; > 20 cm diameter) and 3.6 years for downed CWD. WD stocks and inputs were highly spatially variable, such that the sampling efforts necessary to estimate true values within 10% with 95% confidence were > 130 km of transects for downed CWD and > 550 ha area for standing CWD. The vast majority of studies involve much lower sampling efforts, suggesting that considerably more data are required to precisely quantify tropical forest WD pools and fluxes. The demonstrated importance of elevated WD in our study indicates a need to understand how elevation above the ground alters decomposition rates and incorporate this understanding into models of forest carbon cycling.