I examined the consequences of local environmental variation on the seedling establishment of Prunus virginiana, common chokecherry. In western Montana, USA, this species produces large crops of small seeds in mesic riparian habitats and small crops of large seeds in xeric slope habitats. From 1996 to 1999, I manipulated seed and seedling distributions. I altered seed size, density, distance from adult canopies, habitat, degree of protection from seedling predators, and the amount of soil moisture. In riparian habitats, seed dispersers tended to deposit seeds away from fruit tree canopies, and seedling establishment was greater away from canopies than under them. In both riparian and slope habitats, large seeds were more likely to be depredated than small seeds. However, seed and seedling depredation were more intense in riparian habitats. In slope habitats, seedling establishment was greatest under fruit tree canopies, where seed deposition by frugivores was most likely. In this habitat, large seeds produced seedlings with higher growth rates, and desiccation, rather than depredation, was the predominant cause of seedling mortality. In slope habitats, seedlings from small seeds experienced reduced survival when I did not provide supplemental water. On slopes, the importance of large seed size for seedling establishment may override the negative effects of size on dispersal likelihood. Because the canopy of slope plants may have overall positive effects on establishment, dispersal may be relatively unimportant or even undesirable. In contrast, in riparian habitats, the production of small, highly dispersible seeds may be critical because it reduces the negative effects of parental canopies.