Alan,
Wayne's question, as he was standing on the ridge behind the 9th green was:
"Are the trees too important for the stability of the hillside to remove?
Does it matter?"
My position is that the Pines on top of the ridge are not instrumental or important to the stability of the steep bank behind them due to the shallow nature of the root system of the pines.
A root system that only entends 6 to 18 inches below the surface isn't going to migrate down to the slope of that steep bank and stabilize it..
If you wanted to stabilize the steep bank below the ridge, you'd use Oaks or other trees known for extensive and deep root systems, root systems that would go down 6 to 20+ feet. Root systems that would become invasive to that steep bank.