I'm guessing that in future years your trees will be taking more and more water from the pond as the trees get bigger and bigger. Their impact on the water level may not be all that noticeable in a wet year, but in a dry year they will be trying to get the water they need from the nearest available source. Tree roots naturally grow towards their water source; that's why they have a tendency to plug sewer lines.
What about cutting down only some of the trees? That would leave some shade, cut down on the amount of leaves, and cut down on the amount of water they are stealing from the pond, especially if the trees you kept were the ones that were further back from the pond.
As for burning the leaves while they are on the trees, it's likely that the heat from the burning leaves would damage the end buds for next year's growth. You might end up with trees that looked like they were "topped", with new branches coming out everywhere. Even if this didn't happen the heat would cause some damage to the buds and limbs, weakening the tree so that over several years of burning the tree would gradually die.
On the other hand, if you are going to cut them down anyway, it would be a neat experiment!
Last edited by HaBi Farm; 09/29/20 09:00 AM. Reason: spelling/syntax