Strange Behavior With Aspen Trees

 Top photo shows the small twigs that have fallen off the aspen trees. The ground is littered with them. The second photo is a twig that still has the aspen leaves attached and the leaves are dry.

 The third photo reveals all the dry/green aspen leaves on the ground that the aspen trees are dropping.

I

The only thing I can figure is that following the wild fire thousands of small aspens popped up and they are draining the root system which connects all the trees from needed nutrients for the bigger trees. The humidity is 9-12, and we have only had 1/2" of rain in the past two months. My guess is the trees are doing this to survive as a family of trees. I don't really know but it is super dry and the ground is very dry.
If anyone knows why the aspen trees are doing this - please advise...