Four methods of determining leaf area index of three successional hardwood forests in northern lower Michigan were compared. Direct harvests gave values for leaf area index ranging from 1.4 to 3.6. Estimates of leaf area index derived from litter fall data were consistently higher that the harvest values and were highly dependent on the ratio of leaf area to leaf mass, which had to be estimated. A visual method using sightings through a tube gave values consistently lower (by 27-42%) than the harvest values. Calculations of leaf area index based on regressions of leaf mass versus tree diameter gave results very close to the harvest values for each site as a whole; calculations for smaller plots were more variable. The harvest method allowed measurement of the vertical distribution of leaf area; the other methods could not do so.