Hello Cougar,
It probably depends on the amount of trees to burn vs the volume of water that will be in the pond.
My second pond is about 8 acres right now and we burned several brush piles in the bottom before it filled up. My bluegill are spawning on top of one of the burned brush piles right now. I think the like how easy it is to build a nest in the ashes.
That's just my experience. Things could be different with more brush and less water??
