How far to set back trees from a pond is a problematic question. My pond edge sits probably a hundred feet south of my house. I have trees on the south side of my house so they are probably 80 feet from the pond. Should not be a problem, right?
Well they are. Not a big problem, but in the fall when the leaves fall and the northwest winds howl here in Kansas, a good portion of the leaves end up stopping their windward journey right in our pond.
So absent sawing every tree within a quarter mile, which is not a desirable alternative, tree leaves causing nutrients being added to a pond is just a problem.
Not the answer you wanted to hear. Maybe you don't have wind that blows towards your pond. That would be very helpful. Outside of living in a treeless prairie, my only input is just keep the tree location in mind with your planning. Further away is better for the pond. But not necessarily for pond and landscape aesthetics. So whatever you do is going to be a compromise. Just try to avoid having them right up next to the pond if possible. Even my half dozen trees 80 feet away from the pond add some nutrients each year.
