I suspect that it is not so much that the pines and the under growth diverted the runoff as it is they absorbed it. That many trees and that heavy under brush require HUGE amounts of water and the roots keep the soil loose and ready to suck up any water available. My advice, keep the underbrush and accumulated pine needles to a minimum going forward. There is a good market for pine needle straw. My BIL has acreage in pines in Florida (not far from Dothan) and the buyer comes and harvests the needles and writes him a check!
The rule of thumb I've read is keep the trees at least 50 feet away from the pond unless you want them tapping into the pond as a water source.
Just my 1 cent....
Good advice. Though I will say that having felling a few pines on the shoreline into the water helps create good structure. Bob L says to leave up dead trees where it is safe, as they will harbor many species, especially birds.
