Impact des routes forestières sur la biodiversité floristique : synthèse de trois études menées en forêt de plaine

Three studies conducted in two State forests (Orleans and Montargis) highlight the multiple roles played by forest roads in relation to plant biodiversity: roadsides provide habitats for non-forest species but are detrimental to some forest species. Protected species and neophytes species are also found on roadsides. Two areas of concern are highlighted: (1) the forest paths opened for regeneration felling and harvesting machine traffic that increase the span of the road effect up to 60 m by facilitating introductions of non-forest species in the interior of forest stands and pushing forest species much further from the road; (2) the use of limestone gravel for road improvement in a native nutrient-poor environment increases soil pH and is detrimental to acidophilic species. To protect forest soil and plant biodiversity, we recommend reducing reconsidering the density of forest roads and forest paths and using road materials that do not modify the pH of the adjacent forest soils.