I'm glad I've been adamant (and downright witchy!) about not letting folks cut down my not-dead-yet pecan tree. Over the last month, I've seen at least six different birds use it, including a pair of red-cockaded woodpeckers.
Is the tree pretty? Not really. But I don't care. As I recently told An Insulting Person, my garden and yard is all about the wildlife it supports---that's my main focus. And I'm sticking to it. As long as the dead tree is safe for humans and in no danger of falling over, then we'll be leaving it alone.
This short article from the US Department of Agriculture Forest Service explains the reason why leaving those trees alone is a good idea.
"Wildlife need dead, hollow or fallen trees
for food and family homes. Nearly all wildlife species benefit from
"animal inns" for food, nesting or shelter. The forest neighborhood
changes, yet the way animals, plants and people depend on each other
remains the same. Even as a tree dies, it continues to help sustain life
to animal families and eventually to new plants and trees, and the
cycle begins again. Please don't cut trees with: paint marks, wildlife
signs, broken tops, trunk holes or visible nests, and any other trees
prohibited by permit."