Pest damage in mixed forests: Disentangling the effects of neighbor identity, host density and host apparency at different spatial scales

摘要: Mixed forests are thought to be less prone pest insect damage than monocultures. This may result from reduced host availability (i.e., density effect) or non-host trees reducing the physical chemical apparency of associational resistance, AR). However, and effects often confounded in mixed forests. We aimed disentangle their relative contribution attacks pine by a specialist pest, processionary moth (PPM, Thaumetopoea pityocampa). assessed infestation PPM counting number winter nests during three consecutive years along an experimental gradient presence absence fast growing species, namely birch. The total per plot increased with (maximum high monocultures), while proportion attacked decreased same gradient. Birch provided resistance via due greatest higher. mechanism occurred at two spatial scales, whenever birch was planted within plots adjacent plots. Associational stronger dense stands, probably distance between pines neighboring birches. But AR faded time, becoming taller birches, making preeminent over effects. Our findings suggest that mixing tree species trigger insects requires taking into account growth rate associated together both stands. © 2016 Elsevier B.V.