Attached and freshly fallen leaves were collected in the fall of 1959 from 3 forests in southern Ontario. Outline drawings of the leaves were made on graph paper, and holes made in the leaves by herbivores and fungi also were outlined. Calculations were made of the leaf area consumed and its proportion of the total leaf area. The number of trees and their basal areas were estimated from random quadrats. Results are tabulated. The mean leaf utilization in the stand was estimated by weighting the species values to the basal area of the species per ha. The total photosynthesis for Fagus is estimated at 24.0 tons of dry material/ha/yr., and the leaf loss is 11.4% of this. Photosynthesis of Fraxinus excelsior is 21.0 tons/ha/yr., and loss is 13.3%.