Welcome to the forums gard73. I've seen pic's of brasscia growing great in well prepared shaded plots in the middle of the woods. Maybe you could pruner saw some branches away from your plot instead of killing the trees. I think durana needs atleast 4 hours of direct sunlite to grow well. You might try a BFO/brassica mix in a shaded area, maybe even throw some buck wheat down for good measure. The thing is not to limit your forages, that way you'll end up with atleast something to draw deer in the fall.
"Let a young buck go, so he can grow."