Mike the experts will want the details re the pond
length, width, depth. Leaves and ponds are bad so reducing them by removal has got to be good. We have a similiar problem, my 100x300 pond is surrounded by birch trees, its about 7 foot deep at its deepest. I have had an estimate to pump out the muck ($3,000) and an estimate to deepen it ($3,000) by a few feet. I opted to start with an aerator ($500) as apparently the bubbles ie oxygen help with muck reduction...and fish like it too