The use of wooden (modified Stratmann) boxes by bats was studied in three different tree stands (80-year old beech forest, 150-year old oak-beech forest with admixture of pine, 50–70-year old pine forest) of a managed woodland (Darżlubska Forest) in northern Poland. Two species (Pipistrellus nathusii and Plecotus auritus) inhabited these boxes after 2–13 months. The occupation of shelters in pine monoculture was several tens of times higher than in both deciduous forests. The main factors responsible for such differences are: 1) almost complete lack of natural roosts (tree holes) in young pine forest, 2) unfavourable (colder and more humid) microclimate in broadleaf (especially beech) forests, 3) much higher abundance of some invertebrates (mainly gastropods), that make boxes in beech forest unattractive for bats.