Vegetation limits the impact of a warm climate on boreal wildfires
Vegetation limits the impact of a warm climate on boreal wildfires
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DOI：
10.1111/nph.12322
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发表时间：
2013-09-01
期刊：
影响因子：
9.4
通讯作者：
Bergeron, Yves
中科院分区：
文献类型：
--
作者：
Girardin, Martin P.;Ali, Adam A.;Bergeron, Yves
有人建议将易燃程度较低的阔叶植被战略性地引入景观，作为减少气候变化下预计的北方野火风险的管理战略。然而，这种抵消效应在实际环境中的实现和强度仍有待证实。在这里，我们结合古生态数据、全球气候模型和野火模型来评估北方森林的区域火灾频率(RegFF，即经过一段时间的火灾数量)，因为它与树种组成和千年尺度上的气候有关。来自加拿大东部北部北部景观的湖炭表明，中期全新世(6000-3000年前)的RegFF显著高于工业化前的RegFF(公元1750年)。在南部地区，尽管干旱严重程度有所下降，但区域气候变化框架并没有明显高于工业化前的区域气候变化框架。模拟实验表明，全新世中期南方气候变暖和干燥所带来的高火灾风险被较高的阔叶成分所抵消。我们的数据突出了阔叶植被在确定气候变暖的北部地区的重要作用。我们估计，它的反馈可能足够大，足以抵消气候变化对干旱条件的预测影响。
Strategic introduction of less flammable broadleaf vegetation into landscapes was suggested as a management strategy for decreasing the risk of boreal wildfires projected under climatic change. However, the realization and strength of this offsetting effect in an actual environment remain to be demonstrated.Here we combined paleoecological data, global climate models and wildfire modelling to assess regional fire frequency (RegFF, i.e. the number of fires through time) in boreal forests as it relates to tree species composition and climate over millennial time-scales.Lacustrine charcoals from northern landscapes of eastern boreal Canada indicate that RegFF during the mid-Holocene (6000-3000 yr ago) was significantly higher than pre-industrial RegFF (AD c. 1750). In southern landscapes, RegFF was not significantly higher than the pre-industrial RegFF in spite of the declining drought severity. The modelling experiment indicates that the high fire risk brought about by a warmer and drier climate in the south during the mid-Holocene was offset by a higher broadleaf component.Our data highlight an important function for broadleaf vegetation in determining boreal RegFF in a warmer climate. We estimate that its feedback may be large enough to offset the projected climate change impacts on drought conditions.