The Reason why none of these trees might not be present could be quite simple, obviously deforestation is going take care of most of these trees, then you get Wood Beetles and various diseases, and then drought. I remember when I was a kid we used to have quite a few Quaking Aspens where I lived, and then there was a Disease that literally wiped out a good 99% of them, seventeen years later, and you would never know that they ever existed here in the first place. I mean you can't even find traces of them above the soil in the mountains where there used to be large thickets of them.