An investigation was carried out to determine the factor or factors causing the paucity of reproduction by seeds of Fagus grandifolia in southern Wisconsin, as contrasted with the relatively abundant reproduction by seed in the northern part of the state. A greater percentage of viable seed was found to occur in northern conifer–hardwood forests than in southern hardwood forests. The results of in vitro tests suggested that pollen from trees in northern conifer–hardwood forests has a higher percentage germination and produces longer pollen tubes than that from trees found in southern hardwood forests. Parthenocarpic development was observed but the seeds from such fruits were not viable. Quantitative studies on seedling survival showed higher survival rates in the mor humus of northern conifer–hardwood stands than in the mul humus of southern hardwood stands. The study suggests that the relatively high success of beech reproduction by seeds in northern conifer–hardwood forests is related to both higher seed viability and more favorable conditions for seed germination and seedling survival. Geographic location of stands appears less important than forest type to the success of beech reproduction by seed.