As arborists, our preference is always to preserve a tree if it can be done safely. Mature trees provide shade, privacy, and property value that take decades to replace. But some situations leave no viable alternative to removal. Here are seven signs that a tree needs to come down.
1. The Crown Is Mostly Dead
A tree that has lost more than 50% of its canopy — whether to disease, drought, pest damage, or decline — is unlikely to recover. Half-dead trees are structurally unpredictable: the dead portions become brittle and prone to sudden failure, while the living portions continue to grow and add weight and wind resistance. If more than half your tree's crown is dead or dying, removal is typically the right call.
2. There Is Significant Hollow or Decay in the Trunk
Some hollowing is manageable, but when internal decay has compromised a significant portion of the trunk's cross-section, the structural risk becomes unacceptable. A qualified arborist can assess the extent of internal decay using probes or resistograph testing. If the shell wall is too thin to support the tree's weight and wind load, it needs to come down.
3. The Tree Has Developed a Dangerous Lean
A sudden lean — especially one accompanied by soil heaving on one side — indicates root failure. Unlike a natural gradual lean that a tree has grown with over years, a sudden lean can precede rapid and complete failure. This is an emergency situation.
4. Major Surface Roots Are Damaged or Severed
Construction, trenching, grading, and soil compaction can destroy critical portions of a tree's root system. A tree may look healthy above ground for years after major root damage before suddenly declining or failing. If significant root damage has occurred, an arborist assessment is essential.
5. The Tree Has Significant Storm Damage
Not all storm damage is fatal — a tree that loses a major branch but retains most of its crown and structural integrity can often recover. But when the main trunk is split, bark is stripped down the trunk, or more than half the crown is gone, removal is usually the safest and most practical option.
6. The Tree Is Infected with a Lethal Disease
Some tree diseases are fatal and untreatable once established. Emerald Ash Borer, Dutch Elm Disease, and advanced Oak Wilt are examples where, once the tree is significantly affected, removal is the only option. Prompt removal also reduces the risk of spreading to neighbouring trees.
7. The Tree Is Threatening a Structure or Utility Line
A structurally sound tree that is growing into a building, damaging foundations, or in contact with power lines may need to be removed even if it is otherwise healthy. The risk of property damage and the ongoing cost of repeated trimming often make removal the more practical long-term solution. Call your utility provider immediately if a tree is in contact with power lines — never attempt to cut it yourself.
