No leaves during the growing season
Brittle, dry twigs that snap easily
No buds forming in spring
Bark peeling off in large sections
No green layer under the bark when scratched
Branches that are dry and hollow-looking
Fungal growth on trunk or roots
Large areas of dead wood in the canopy
No new growth at the tips of branches
Tree leaning suddenly or showing root damage
Trunk soft, cracked, or decayed
No sap flow when bark is cut slightly
Roots exposed, rotting, or severed
Tree remains leafless while nearby trees are healthy