Let's see the root-collar/ the base.
I'm going with chronic drought-stressed western hemlock, possibly with a side order of annosus root and butt-rot.
Any construction impact to the root zone (Critical Root Zone is 1' of radius for each inch of trunk Diameter. CRZ has about 80% of the roots, if unobstructed by a pavement/ foundation/ etc. Septic? Filling of grade or excavation of grade?
Borax on the stump, day of removal. ASAP, reasonably. Or grind the stump.