I have a 1 1/2 acre pond in S.C. that had trees behind it. This pond was originally built before the civil war. The trees behind the pond never bothered the dam, but previous owners allowed trees to grow on the dam which finally took its toll. I rebuilt it one year ago, left the beautiful trees behind the dam that I felt would not harm it. It just depends on what you want to enjoy. Although I won't allow a tree to grow on my dam, I could never destroy the beautiful trees behind the dam, unless they were so close to hurt the dam. I enjoy the spring and wetlands that fill the pond, but I also enjoy the wildlife and vegetation below the pond.