I think you should stay far enough from the trees that their roots will not get to the pond area. When they die, their rotted roots leave a "hole" that just might let pond water find an outlet. Maybe go 2 or maybe even three times the dripline. Maybe no problem but you will always be wondering.

Is there any chance that the creek could flood your pond? If so, both the water and fish could run both ways. You should also expect fallen leaves to enter the pond as a sludge buildup. I don't clear mine and I know it happens.

Have fun!