Bees in the trees: Diverse spring fauna in temperate forest edge canopies

•Despite equal species richness among strata, woodlots had vertically stratified bee communities.•We found higher overall diversity and more female bees in the canopy.•The traits of nesting habitat and sociality were strongly predictive of strata occupancy.•Canopy cover (leaf-out) was negatively associated with understory but not canopy bee abundance.•Regional amount of coarse woody debris correlated with understory abundance of some trait groups.•We speculate females forage for canopy pollen; we recommend maintaining above-ground deadwood.