Effect of a hardwood forest canopy on rainfall intensities

Ground rainfall intensities and throughfall were measured under a fully‐stocked hardwood forest in West Virginia over a period of one year. Maximum 5‐ and 15‐min intensities were compared with similar measurements made in the open. The results were analyzed separately for winter and summer conditions; that is, bare canopy versus canopy in full leaf. Regression equations were calculated for estimating intensities and throughfall under canopy from rainfall measurements made in the open. The study shows that low rainfall intensities are reduced more by summer canopy, and high intensities are reduced more by winter canopy. Throughfall is reduced by canopy interception approximately the same amount in both summer and winter.