Atmospheric deposition of contaminants to forests may significantly influence the cycling of these contaminants in terrestrial ecosystems. To investigate the exchange of trace elements between the atmosphere and a forest canopy, a throughfall study was conducted during the 1996 growing season at UMBS in Pellston, Michigan. Event, wet-only throughfall and precipitation samples were collected from multiple automated samplers using clean, trace metal sampling techniques. Sampling began prior to bud break and continued until after leaf senescence (June-November, 1996). The exchange of elements between the forest canopy and the atmosphere, as measured in net throughfall deposition (throughfall deposiiton minus precipitation deposition), indicated that elements were both released and absorbed by the forest canopy. The net throughfall deposition of some elements was relatively uniform, suggesting atmospheric deposition as the source. The net throughfall deposiiton of other elements was highly variable, indicating species differences in foliar leaching. Elements which were washed off the foliage include Pb, As, Cd, and V; elements were leached from the foliage include Mn, Ba, and Rb. Some elements were both released and absorbed by the canopy (Zn, Cu, Ni, and Hg). The increased deposition of contaminants in throughfall may influence or alter the cycling of both nutrients and contaminants in terrestrial ecosystems.