Forest & Nature Lab, Department of Environment, Ghent University, Gontrode-Melle, Belgium.
Forest Ecology and Conservation Group, Department of Plant Sciences, University of Cambridge, Cambridge, UK.
Nat Ecol Evol. 2019 May;3(5):744-749. doi: 10.1038/s41559-019-0842-1. Epub 2019 Apr 1.
Macroclimate warming is often assumed to occur within forests despite the potential for tree cover to modify microclimates. Here, using paired measurements, we compared the temperatures under the canopy versus in the open at 98 sites across 5 continents. We show that forests function as a thermal insulator, cooling the understory when ambient temperatures are hot and warming the understory when ambient temperatures are cold. The understory versus open temperature offset is magnified as temperatures become more extreme and is of greater magnitude than the warming of land temperatures over the past century. Tree canopies may thus reduce the severity of warming impacts on forest biodiversity and functioning.
尽管树木覆盖可能会改变小气候，但通常认为森林内部会出现宏观气候变暖。在这里，我们使用配对测量的方法，在跨越五个大洲的 98 个地点比较了树冠下和开阔地的温度。结果表明，当环境温度较高时，森林起到了隔热作用，使林下温度降低；当环境温度较低时，森林起到了保温作用，使林下温度升高。随着温度变得更加极端，这种林下与开阔地的温度差值会被放大，其幅度大于过去一个世纪陆地温度的升高。因此，树冠可以降低森林生物多样性和功能受到变暖影响的严重程度。
