Using data from about a hundred sites worldwide, an international research team has demonstrated that forest cover acts as a global thermal insulator, by cooling the understory when the air temperature is high. This buffer effect is well known, but this study is the first that has evaluated this worldwide in temperate, boreal and tropical forests. Maximum temperatures are on average 4°C lower in forests than outside them, with much higher differences for tropical forests than for the others. The researchers have also shown that the hotter the external conditions, the greater a forest's buffering capacity.
On the basis of this observation, management strategies can be proposed to improve forest microclimates and limit the harmful effects of global warming on biodiversity. This study published in Nature Ecology & Evolution on 1 April 2019 was an initiative by Pieter De Frenne at the Université of Ghent and Jonathan Lenoir, CNRS researcher at the Laboratoire Écologie et Dynamique des Systèmes Anthropisés (CNRS/Université de Picardie Jules Verne).