Free evolution of forests and control of the health risk associated with conifer bark beetles

摘要

© AgroParisTech, 2019.Temperate forests are experiencing a sharp increase in insect pest attacks in response to climate change, as evidenced by the recent rise in conifer bark beetle outbreaks. As a result of the banning of insecticides and the deadline of genetic selection, the best option remains to adapt forest management in order to prevent or control these infestations. In terms of prevention, increasing the diversity of forest species by combining coniferous and deciduous trees reduces the density of host trees, increases their vigour, disrupts colonization processes and maintains natural enemies, and this improves the overall resistance of stands to bark beetle attacks. In terms of control, sanitation harvestings to remove trees infested by bark beetles and reduce their breeding substrate are rarely effective, unless they are carried out rapidly and target almost the entire volume of windfall. Therefore, long time unmanaged forests do not appear to be intrinsically more vulnerable to bark beetle attacks, provided that they are composed of a balanced mixture of contrasting tree species.