Found this tree along Spicebush trail in Rondeau Provincial Park.
This is an ash tree that has been infested by the emerald ash borer.
The insect bores its way underneath the bark and destroys the cambium layer that is the living portion of a tree.
Vascular cambium does not transport water, minerals, or dissolved food through the plant. it does produce the phloem and xylem which perform these functions.