Well, clearing the trees is already a profitable opportunity, if that is what happened. But my guess is we are talking about the idiosyncratic decisions of one landowner. Who knows if they did any kind of serious cost-benefit analysis. Or were you assuming that a solar company bought the land specifically to install solar. Possibly, but that's hardly clear to me. Besides, in the mountains, wind is probably the better bet.
Now .. putting solar farms on top of already strip mined mountains makes sense to me. You've already flattened them, and farming is of the question. And it ... looks like that is happening. Tjough I don't know how the Surface Mining Control and Reclamation Act plays into that.