Land cover influences boreal-forest fire responses to climate change: geospatial analysis of historical records from Alaska
Land cover influences boreal-forest fire responses to climate change: geospatial analysis of historical records from Alaska
复制标题
土地覆盖影响北方森林火灾对气候变化的反应：阿拉斯加历史记录的地理空间分析
作者：
C. Dash;J. Fraterrigo;F. Hu
预计北方森林的野火活动将因人为气候变化而急剧增加。通过改变燃料的空间排列，土地覆盖配置可能与气候变化相互作用，影响景观和区域尺度的火灾动态。目标我们评估土地覆盖如何与天气条件相互作用，以影响阿拉斯加2012年至2014年的北方森林燃烧。方法使用地理空间火灾和土地覆盖数据，我们量化了烧毁面积和土地覆盖之间的关系，并测试在不同的天气条件和火灾规模下观察到的燃烧模式是否与随机模式不同。结果平均夏季湿度指数与年燃烧面积相关（ρ =-0.78，p < 0.01）、火灾总数（ρ =-0.68，p = 0.01）和大火数量（>500平方公里; ρ =-0.58，p = 0.04）。被烧毁的面积与针叶林和木本湿地的覆盖率呈正相关，与灌木灌丛、矮灌丛、开阔水域和贫瘠地区的覆盖率呈负相关。火灾优先烧毁针叶林，在温暖/干燥的夏季占烧毁面积的50.1%，在凉爽/潮湿的夏季占烧毁面积的40.3%，相比之下，随机选择的土地覆盖类别预计为34.5%（± 4.2%）。整体植被往往燃烧更相似的随机在温暖/干燥比凉爽/湿润years.ConclusionsLand cover施加更大的影响，北方火制度时，天气条件不太有利于森林燃烧。因此，对北方火灾状况变化的可靠预测需要考虑气候与土地覆盖之间的相互作用以及土地覆盖变化的反馈。
ContextWildfire activity in boreal forests is projected to increase dramatically in response to anthropogenic climate change. By altering the spatial arrangement of fuels, land-cover configuration may interact with climate change to influence fire-regime dynamics at landscape and regional scales.ObjectivesWe evaluate how land cover interacts with weather conditions to influence boreal-forest burning from 2012 to 2014 in Alaska.MethodsUsing geospatial fire and land-cover data, we quantify relationships between area burned and land cover, and test whether observed patterns of burning differ from random under varying weather conditions and fire sizes.ResultsMean summer moisture index was correlated with annual area burned (ρ = −0.78, p < 0.01), the total number of fires (ρ = −0.68, p = 0.01), and the number of large fires (>500 km2; ρ = −0.58, p = 0.04). Area burned was related positively to percent cover of coniferous forest and woody wetlands, and negatively to percent cover of shrub scrub, dwarf scrub, and open water and barren areas. Fires preferentially burned coniferous forest, which represented 50.1 % of the area burned in warmer/drier summers and 40.3 % of area burned in cooler/wetter summers, compared to the 34.5 % (±4.2 %) expected by random selection of land-cover classes. Overall vegetation tended to burn more similarly to random in warmer/drier than cooler/wetter years.ConclusionsLand cover exerted greater influences on boreal fire regimes when weather conditions were less favorable for forest burning. Reliable projections of boreal fire-regime change thus require consideration of the interactions between climate and land cover, as well as feedbacks from land-cover change.