The defoliation of montane cloud forest in Puerto Rico by a recent hurricane offers an opportunity to investigate the influence of canopy structure on the deposition of material from the atmosphere and the chemical processing of that material before it reaches the forest floor. Drs. Lovett and Asbury hypothesize that: 1. As the canopy recovers, cloud water deposition will first increase in response to increasing surfaces for deposition, and then decrease as the canopy becomes dense enough to limit penetration of wind and cloud droplets. 2. The canopy will take up NO3-, NH4+, and H+ and release all other ions. The amount of uptake or release will increase rapidly in the initial stages of recovery and then level off at higher levels of canopy surface areas. 3. Because of the abundance of chemically active epiphytes on boles and branches, stemflow chemistry will change more than throughfall chemistry as the canopy recovers. This innovative research takes advantage of a natural catastrophe to investigate the properties of forest canopy- atmosphere interaction. This is an important area of research for global change and atmospheric deposition. Drs. Lovett and Asbury are highly qualified investigators who have experience with sampling and modeling canopy-atmosphere interactions.