The temporal and spatial distributions of flying Diptera have been studied using suction traps hung at three levels and two distances from an emergent hedgerow tree. Most families were far more abundant in 1987 than in 1986, but patterns of spatial and temporal abundance were basically the same. Most families showed a marked concentration close to the tree. Scatopsidae accumulated away from the tree in large numbers. Most families concentrated at the mid-level, except the Anisopodidae and Mycetophilidae (top and bottom levels, respectively). Vertical distributions showed discontinuities for almost all families. It is suggested that the emergent hedgerow tree plays a very important part in the life of flying insects.