Not the best picture but in a sea of evergreens there are lots of bright orange coloured trees, to me these looked a lot like dead pine trees and assumed that this was mountain pine beetle damage. Much like that in the picture below.
Of course, I'm wrong, the trees in the previous picture are Tamarack Larch, a deciduous coniferous tree while the bottom picture is of mountain pine beetle infestation. I actually thought that the terms deciduous and coniferous were mutually exclusive taxonomic catagories. My ignorance knows no bounds.