Certified arborists follow FEMA criteria to determine if a tree is a “hazard tree." Hazard trees are dead or dying trees that will present an eminent threat to the traveling public within a five year timeframe. Watch a video about how we evaluate hazard trees.
Wildfire is devastating to a tree's structural integrity, and structural defects are the primary indicators that a tree is a hazard. Obvious signs are fire damage to the lower trunk or roots. Wildfire burns very hot and can damage a tree's base, making it susceptible to falling over, especially in rough winter weather.
Other signs, like a damaged interior, are harder to spot. Trees with pre-fire holes or damage are especially vulnerable to fire. The fire can enter through these old wounds and burn through the interior of the tree, hollowing it out and killing it. The dead tree might still appear healthy on the outside — especially near the top — but this is deceiving. Inside, the tree is a charred cavity, making it unstable and dangerous.
Where a tree is standing can factor in to whether or not it's a hazard. Typically, hazard trees are cut down if they're within a distance of 1.5x their height from a roadway. Hazard trees near public areas, like trails or parking lots, must be cut down, too. We're also evaluating trees near debris cleanup work areas, in order to keep our crews safe.
Burned trees that are away from roads or cleanup work areas may still be a hazard if they're on steep terrain. Burned trees on steep terrain can fall and roll down the hill, becoming dangerous projectiles. That's why you might see hillsides being cleared of trees, especially on hills are near roadways.