Arboreal arthropod communities from three reserves of podocarp-hardwood rainforest in the North Island, New Zealand, were sampled continuously between June 1995 and May 1996 using omnidirectional window traps. Diptera made up 34% of the total number of arthropods captured, whereas Coleoptera contributed 12% and Araneae 11% to the total catch. The relative abundance and species richness of Diptera peaked in spring, Coleoptera in summer, and Araneae in autumn. Multivariate analysis of overall community structure suggests that season is the dominant determinant of community structure in the arboreal arthropod communities of these forest patches, whereas site, and to a lesser extent tree species, have minor effects. Given that 863 morphospecies were collected, the conservation value of small forest patches for forest-dwelling arthropods in New Zealand should not be underestimated.