Tree work safety

The physics are what get people. A limb under tension does not fall where you expect it to. A chainsaw pinched in a compressed cut kicks back toward your face. A tree with internal decay can barber-chair and split up the trunk. None of this is visible from the ground, and none of it is intuitive. The International Society of Arboriculture puts it plainly: tree work "should be done only by those trained and equipped to work safely in trees."

Power lines are an absolute stop. Not "be careful" — stop. Electricity can arc; you do not have to touch a conductor to be killed by one. Trimming near energized lines is done by line-clearance qualified workers, a specific category of trained personnel. If a branch is anywhere near a service drop or a distribution line, call your electric utility. Most utilities will clear vegetation around their own lines at no cost to you, and they will tell you where their responsibility ends and yours begins.

Two standards define competent work. ANSI A300 is the family of standards for tree care practices — pruning, cabling and bracing, root management, and so on. ANSI Z133 is the safety standard for arboricultural operations; ISA lists the current edition as ANSI Z133-2026. A contractor who cannot tell you what A300 pruning means is not doing A300 pruning.

After a storm, the risk goes up sharply, not down. Downed limbs are loaded with stored energy, trees may be leaning on structures, and lines may be live in the debris. Assume every downed wire is energized. Stay away and call the utility first, the tree company second.

How to choose

Head height is the line

If you have to reach above your head or stand on anything to make the cut, hire it out. This single rule prevents most homeowner tree injuries.

Never use a chainsaw from a ladder

A ladder gives you no stable base for kickback and no escape route. Professionals use climbing systems or aerial lifts precisely because ladders do not work for this.

Any power line means call the utility

Service drops to your house, distribution lines on the street — both. Contact your electric utility and let them assess. Do not let a general tree crew work near energized conductors unless they are line-clearance qualified.

Ask contractors about A300 and Z133 by name

"Do you prune to ANSI A300, and does your crew work to Z133?" A legitimate company answers immediately. A blank stare is your answer.

Treat storm-damaged trees as loaded, not broken

A hung-up limb or a partially uprooted tree stores enormous energy. This is the single most dangerous condition in residential tree work and it is not a DIY situation at any size.