A tree-ring study was conducted in conjunction with the integrated watershed study of acid deposition effects at Emerald Lake. Tree cores were collected from western white pine and lodgepole pine. Age trends were removed from crossdated ring-width series, which were then combined into chronologies. Both chronologies revealed historical periods of reduced growth within the last four centuries, but no evidence of an obvious decline currently occurring. However, it is possible that there are subtle effects of air pollution present that are masked by the currently more limiting influence of climate. Recommendations for further study were made.