Fire after clear-cut harvesting minimally affects the recovery of ecosystem carbon pools and fluxes in a Great Lakes forest
Fire after clear-cut harvesting minimally affects the recovery of ecosystem carbon pools and fluxes in a Great Lakes forest
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砍伐后的火灾对五大湖森林生态系统碳库和通量的恢复影响最小
DOI：
10.1016/j.foreco.2022.120301
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发表时间：
2022
影响因子：
3.7
通讯作者：
Gough, Christopher M.
中科院分区：
文献类型：
--
作者：
Clay, Cameron;Nave, Luke;Nadelhoffer, Knute;Vogel, Christoph;Propson, Brooke;Den Uyl, John;Hickey, Laura J.;Barry, Alexandra;Gough, Christopher M.
有效的森林碳(C)管理需要了解林分替代干扰如何影响演替时间尺度上的碳库和碳通量，以及次生林的生长与未受干扰的森林的生长相比如何。在五大湖上游地区，砍伐后发生的火灾形成了一个百年历史的次生林群，但在这个相对不喜欢火灾的地区，火灾对碳循环的长期影响仍然知之甚少。我们研究了两种不同的林分更替干扰--一种是有火的，另一种是没有火的--在一个世纪的林分发展过程中如何影响C池和C通量，比较了次生杨(杨树)林和传统的晚期演替林分，这些林分包含了今天在没有林分替代的情况下普遍存在的年龄和物种组成。我们在密歇根大学生物站(UMBS)的工作使用了在砍伐或砍伐后着火建立的实验林时间序列，以及130年后期演替落叶阔叶林(DBF)、常绿针叶林(ENF)和混交林(Mix)三种森林功能类型。无论采伐后是否发生火灾，总(地上和地下)生态系统碳质量、净初级生产力(NPP)和净生态系统生产力(NEP)的演替轨迹和数值都是相似的。此外，80岁以上的次生林的碳库和碳通量与演替后期的生态固氮和混交林相当，但有时低于DBF。虽然百年次生林和传统林在上个世纪一直是C汇，但近年来更极端的温度可能会加速土壤中的C流失，从而侵蚀NEP。我们的结论是，火和皆伐收获的复合效应类似于单独的皆伐收获，可能是因为先锋物种，尤其是杨树对干扰的适应特性；然而，我们的结果也表明，气候变化而不是先前的干扰可能危及这种长期陆地碳汇的未来。
Effective forest carbon (C) management requires an understanding of how stand-replacing disturbances affect C pools and fluxes over successional timescales, and how the growth of secondary forests compares with that of undisturbed forests. In the upper Great Lakes region, fires that followed clear-cut harvesting shaped a century-old cohort of secondary forests, but the long-term effects of fire on C cycling in this relatively fire-averse landscape remain poorly understood. We examined how two different stand-replacing disturbances – one with and the other without fire – influenced C pools and fluxes through a century of stand development, comparing secondary aspen-dominated (Populus) forests with legacy late successional stands encompassing the ages and species compositions that would be prevalent today in the absence of stand replacement. Our work at the University of Michigan Biological Station (UMBS) used experimental forest chronosequences established following clear-cut harvesting or clear-cut harvesting followed by fire, along with three > 130-yr-old late successional deciduous broadleaf (DBF), evergreen needleleaf (ENF), and mixed (MIX) forest functional types. The successional trajectories and values of total (above- and belowground) ecosystem C mass, net primary production (NPP), and net ecosystem production (NEP) were similar regardless of whether fires occurred following clear-cut harvesting. Moreover, 80 + year old secondary forests’ C pools and fluxes were comparable to late successional ENF and MIX, but were at times lower than DBF. While the century-old secondary forests and legacy stands served as consistent C sinks over the last century, more extreme temperatures in recent years may be eroding NEP by accelerating C losses from soils. We conclude that the compounding effects of fire and clear-cut harvesting were similar to those from clear-cut harvesting alone, possibly because of the disturbance-adapted properties of pioneer species, most notably aspen; however, our results also suggest that changing climate rather than prior disturbance may jeopardize the future of this long-term terrestrial C sink.