I recently built 8.5 acre pond; there was about 20% tree coverage. I took down 80% of the trees - burned some and used many for cover. I left 5% standing and had the big excavator knock off the tops off 15% of them, leaving the main trunk a few feet above the water line.

Its two years old now; the stocked fish are doing really well. There is a lot of cover. I wished I would have just knocked them all down and stacked for cover. I think the ones I left standing will be two hard to fish around when the limbs start coming down. The ones that i knocked the tops off will be a little easier to fish around.

When stacking for cover try to place the main trunk at a 45 degree angle to the bottom vs just laying flat.

What kind of trees do you have? If it is 100% oak I'd be nervous to leave all of them in there as the oak will yield tannins that could be toxic to fish on down the road. I didn't have oak; just pecan, hackberry, elm and cedars.

Only two trees left standing were near any of the dam construction; those are in very shallow water - all of the others were well far away from the dam so I am not concerned about them causing future leaks with root decay.