Tropical forests post-logging are a persistent net carbon source to the atmosphere.
Tropical forests post-logging are a persistent net carbon source to the atmosphere.
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DOI：
10.1073/pnas.2214462120
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发表时间：
2023-01-17
影响因子：
11.1
通讯作者：
Riutta, Terhi
中科院分区：
文献类型：
--
作者：
Mills, Maria B.;Malhi, Yadvinder;Ewers, Robert M.;Kho, Lip Khoon;Teh, Yit Arn;Both, Sabine;Burslem, David F. R. P.;Majalap, Noreen;Nilus, Reuben;Huasco, Walter Huaraca;Cruz, Rudi;Pillco, Milenka M.;Turner, Edgar C.;Reynolds, Glen;Riutta, Terhi
砍伐的热带森林在全球碳预算中被视为重要的碳汇，因为它们在干扰后重新生长时恢复了木质生物量，但这一假设忽略了生态系统的同时碳损失。我们发现，当量化生态系统碳预算的所有源和汇项时，被砍伐的热带森林是大气碳的净来源。这一来源在伐木后至少持续了10年，这意味着热带森林恢复过程中的碳固存率可能远低于估计。砍伐和结构退化的热带森林正在迅速成为整个热带地区最普遍的土地使用类型之一，通常被认为是一个净碳汇，因为它们经历了快速的树木再生率。然而，这一假设是基于森林生物量清单，记录了碳储存的恢复，但没有考虑到土壤和坏死物质的碳同时损失。在这里，我们使用森林地块和涡度协方差塔来量化和分区净生态系统CO2交换在马来西亚婆罗洲，一个地区，是一个热点的森林砍伐和森林退化。我们的数据代表了整个伐木事件和随后的恢复过程中测量的热带森林的完整碳预算，并发现它们构成了大量和持久的净碳源。与现有文献一致，我们的研究表明，与未采伐森林相比，中度和重度采伐森林的木本生物量增加显着，但这被采伐森林中土壤有机质和枯枝的碳损失抵消。我们估计，中等采伐地块的平均碳源为1.75 ± 0.94 Mg C ha−1 yr−1，不可持续采伐和严重退化地块的平均碳源为5.23 ± 1.23 Mg C ha−1 yr−1，采伐后至少十年仍以这些速率排放。我们的数据直接与默认假设相矛盾，即恢复砍伐和退化的热带森林是净碳汇，这意味着世界热带森林的碳封存量可能大大低于目前的估计。
Logged tropical forests are counted as important carbon sinks in global carbon budgets due to the woody biomass they regain when they regrow following disturbance, but this assumption ignores the simultaneous carbon losses from the ecosystem. We found that, when quantifying all the source and sink terms of the ecosystem carbon budget, logged tropical forests are a net source of carbon to the atmosphere. This source persists at least 10 y following logging, meaning rates of carbon sequestration in recovering tropical forests are likely much lower than estimated. Logged and structurally degraded tropical forests are fast becoming one of the most prevalent land-use types throughout the tropics and are routinely assumed to be a net carbon sink because they experience rapid rates of tree regrowth. Yet this assumption is based on forest biomass inventories that record carbon stock recovery but fail to account for the simultaneous losses of carbon from soil and necromass. Here, we used forest plots and an eddy covariance tower to quantify and partition net ecosystem CO2 exchange in Malaysian Borneo, a region that is a hot spot for deforestation and forest degradation. Our data represent the complete carbon budget for tropical forests measured throughout a logging event and subsequent recovery and found that they constitute a substantial and persistent net carbon source. Consistent with existing literature, our study showed a significantly greater woody biomass gain across moderately and heavily logged forests compared with unlogged forests, but this was counteracted by much larger carbon losses from soil organic matter and deadwood in logged forests. We estimate an average carbon source of 1.75 ± 0.94 Mg C ha−1 yr−1 within moderately logged plots and 5.23 ± 1.23 Mg C ha−1 yr−1 in unsustainably logged and severely degraded plots, with emissions continuing at these rates for at least one-decade post-logging. Our data directly contradict the default assumption that recovering logged and degraded tropical forests are net carbon sinks, implying the amount of carbon being sequestered across the world’s tropical forests may be considerably lower than currently estimated.
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影响因子：
16.6
作者：
通讯作者：
--
影响因子：
2
作者：
Gatti, Roberto Cazzolla;Castaldi, Simona;Valentini, Riccardo
通讯作者：
Valentini, Riccardo
DOI：
10.1098/rstb.2011.0049
发表时间：
2011-11-27
影响因子：
6.3
作者：
Ewers, Robert M.;Didham, Raphael K.;Turner, Edgar C.
通讯作者：
Turner, Edgar C.
影响因子：
3.7
作者：
Feldpausch, TR;Jirka, S;Riha, SJ
通讯作者：
Riha, SJ
影响因子：
11.6
作者：
Kutsch, WL;Liu, CJ;Herbst, M
通讯作者：
Herbst, M