Dead branches and hangers: what the standards and agencies describe

This page describes what published sources say about one structural condition in trees. It gives no verdict on any tree and is not an assessment. The sources come from the United States and the United Kingdom. The parent page, structural defects in trees, compares the conditions that have pages here.

What the sources describe

The US Forest Service brochure describes dead wood as often dry and brittle and unable to bend in the wind like a living branch. It uses the terms hangers and widow makers for dead or broken branches and tops that are already lodged in a tree, and calls them especially dangerous. Its wording is that dead trees and large dead branches must be removed immediately. Its list of reasons to act names a broken branch or top lodged in a tree, a dead tree, and a dead branch big enough to cause injury.

The Illinois Extension article says dead wood does not bend like live wood and is more prone to snapping in high winds, and adds that some species are poor self-pruners and leave dead but relatively harmless branches in the crown. The University of Kentucky leaflet says heavy winds snap off the inflexible dead branches.

What the Florida publication adds

The University of Florida extension publication says dead branches may have loose or missing bark and dead or absent foliage and buds, and that a branch dead for some time may look coarse or stubby as small twigs break off. It says leaves being present or absent alone should not decide whether a tree has died, because some trees are deciduous. It says some decay-resistant species hold on to dead branches for several years but that dropping is inevitable, that dead branches typically break off during storms but may drop in less severe weather, and that large branches high up in a tree are of greatest concern because they can hit a target at higher velocity. It treats broken or partly attached branches as already in a state of failure that can drop in calm weather.

The ISA and the National Tree Safety Group

The ISA Trees Are Good leaflet asks in its checklist about large dead branches, detached hanging branches and branches that have fallen. Item G of its list calls dead branches within the canopy probably the most obvious potential hazards and says the risk of damage or injury depends on the size of the dead branch and its distance from any potential targets. The National Tree Safety Group glossary defines deadwood as woody material no longer physiologically active that stays attached until it falls, and says it is important as habitat for wildlife. The guidance lists heavy dead parts among the signs that might indicate a structural defect, although not necessarily a hazardous one.

Where the sources add a caution

The National Tree Safety Group guidance defines a defect as a condition that predisposes a tree or part of it to structural failure. It treats dead wood as a feature of trees in general, so the presence of some is a description of the tree, not a finding about how it will behave. The US Forest Service brochure says a defect matters where a target, such as a person or property, is within striking distance of the tree.

Who looks at this

For the methods and the credentials, see tree risk assessment methods and consulting arborist credentials. Related conditions are on cracks in trees.