Approximately 100 trees were sampled and mapped in each of three natural Sugar Maple (Acer saccharum Marsh.) stands in northwestern Ontario. Starch-gel electrophoresis was used to resolve five polymorphic enzyme loci from bud tissue and spatial genetic structure was examined in each of the three stands using spatial autocorrelation techniques. A significant small scale genetic structure was detected in all stands and patch widths were inferred to be approximately 20-30 m. A nonrandom distribution of genotypes may be a reflection of restricted gene flow, selection and/or patchy establishment of genetically distinct cohorts.