Temperate forest methane sink diminished by tree emissions
Temperate forest methane sink diminished by tree emissions
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DOI：
10.1111/nph.14559
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发表时间：
2017-06-01
期刊：
影响因子：
9.4
通讯作者：
Megonigal, J. Patrick
中科院分区：
文献类型：
--
作者：
Pitz, Scott;Megonigal, J. Patrick
全球预算将4%-10%的大气甲烷(CH4)汇归因于旱地土壤，直到最近还一直认为土壤是旱地森林中CH4交换的唯一表面。这里我们报告说，CH4是从温带旱地森林中主要树种的树干排放的，使用传统的静态室方法和一种新的高频自动系统进行测量。从5月到9月，对17棵树的68次观测得到的树木排放量平均为1.59+/-0.88亩·甲烷(4)m(-2)树干h(-1)(平均+/-95%可信区间)，树旁土壤对大气CH4的消耗速率为-4.52+/-0.64mmolCH4m-2，土壤h(-1)(P<；0.0001)。高频测量揭示了树干CH4排放速率的日变化规律。一个简单的尺度试验表明，树木排放抵消了生长季节土壤CH4汇的1-6%，并可能短暂地将森林转变为净CH4源。
Global budgets ascribe 4-10% of atmospheric methane (CH4) sinks to upland soils and have assumed until recently that soils are the sole surface for CH4 exchange in upland forests.Here we report that CH4 is emitted from the stems of dominant tree species in a temperate upland forest, measured using both the traditional static-chamber method and a new high-frequency, automated system.Tree emissions averaged across 68 observations on 17 trees from May to September were 1.59 +/- 0.88 mu mol CH(4)m(-2) stem h(-1) (mean +/- 95% confidence interval), while soils adjacent to the trees consumed atmospheric CH4 at a rate of -4.52 +/- 0.64 mu mol CH(4)m(-2) soil h(-1) (P < 0.0001). High-frequency measurements revealed diurnal patterns in the rate of tree-stem CH4 emissions.A simple scaling exercise suggested that tree emissions offset 1-6% of the growing season soil CH4 sink and may have briefly changed the forest to a net CH4 source.