If there is a stream leaving the pond, I get the impression there isn't fish. If there's no fish, then do we worry about PH? As for the trees, unless you want it to look nicer, why move the trees? Nature's wild ponds often have fallen trees. Where else will the turtles bask? But what do I know? Yah, what is your dream about this pond? Maybe you just don't like the look of the duckweed. From what I understand, when it is happy, it grows like the weed it is. HMMM, depth and bottom. I bet it's mucky. Don't mess around in it without someone close by until you learn it's composition. Keep us posted as most of us don't have natural ponds and find this subject interesting because it's different than what we have.