The only trees that I would put around the pond are the trees that Bill listed and maybe some dwarf fruit trees. Leaves getting into the pond are a sure way to shorten the life of the pond.

As for the ducks and geese, that is a hard NO. Keep them out of the pond. If you let them in there the algae problem will be worse and your plants that you planted along the edge will get eaten.

Keep ALL trees off the dam. Period.

www.hoosierpondpros.com

[Linked Image from lh6.ggpht.com]
http://www.pondboss.com/subscribe.asp?c=4
3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).