I pushed two dead live oaks (3' diameter trunk, with 5' diameter root ball, and a few limbs) into my pond for structure upon completion. 3/4 surface acre.
Now, I've added two more un-natural structure elements, and I'm second-guessing the decision. One is 4 285/75/r16 truck tires wired together forming a cube, and the other is my old pipe BBQ pit which rusted through, opened up like pac man trying to munch the bottom of the pond. I thought it would be a good catfish hideout.
The environmentalist/naturalist/purist in me is wondering if I should remove everything but the trees? What do you guys/gals think?