Your Backyard Forest - Identify and Manage Hazardous Tree Defects

High-risk defects are signs of tree failure. Look for seven important tree defects: dead wood, cracks, weak branch unions, decay, cankers, root problems, and poor tree form. These tree defects will be described in the next several sections. Remember: a tree with defects is not hazardous unless some portion of it is within striking distance of a target.


• #1- Dead wood: Dead trees and branches are unpredictable and can break and fall at any time. Dead wood is often dry and brittle and cannot bend in the wind like a living tree or branch. A dead branch and treetop that is already broken off ("hanger" or "widow maker") is especially dangerous.
Act immediately if . . .
• A broken branch or treetop is lodged in a tree. • A tree is dead. • A branch is dead and of sufficient size to cause injury. Typically this is a branch larger than 4 inches in diameter, but this can vary with branch height. Even smaller branches, falling from high in the tree, can cause serious personal injury.)

• #2- Cracks: A crack is a deep split through the bark, extending into the wood of the tree. Cracks are extremely dangerous because they indicate that the tree is already failing.
Act immediately if . . .
• A crack extends deeply into, or completely through the stem. • Two or more cracks occur in the same general area of the stem. • A crack is in contact with another defect. • A branch of sufficient size to cause injury is cracked (typically larger than 4 inches in diameter).