"Blonding" of a tree

Excerpts from the discussion thread at the often-interesting arborists subreddit:

"That is an ash tree that has been stricken with the Emerald Ash Borer. That happens from the woodpeckers going for the larvae. As the woodpeckers go, the outer layer of the gray bark falls off, leaving that brownish color...it's called "blonding." While there are treatments, they can be expensive, and the infestation must be caught much earlier than this. This particular tree is a goner."

"And the price of removal goes up (or at least it should) as the tree's wood gets sketchier. So much of this job is intentionally making wood fall apart the way we want it to; it's way harder when the wood has a chance of randomly disintegrating while we're climbing. EAB is the current poster child of sketchy trees."