[SIKSUKR]

Not sure why clearing the area of trees would not work unless there is almost no sun due to geographical exposure. All houses that had decent sun exposure would have moss if that were the case. I suspect that if were talking about removing existing moss and clearing trees and the problem comes back, I would think that the roof has little sun exposure along with remaining agae/moss inbedded that starts the process all over. The moss needs to be absolutely dead in my opinion by using something along the lines of bleach.