There's a big branch hanging in the tree — what should I do?

A broken limb suspended in the canopy — dangling from a strip of bark, resting across other branches, or wedged into a crotch. Usually a fresh pale tear scar visible on the trunk or parent limb where it came from. Very often directly above a driveway, deck, gate or walkway, because that is where people notice them. Unsupported mass held in place by friction and a bark hinge. There is no mechanism keeping it up that you can inspect or trust, and release does not require wind — plenty come down on still mornings. The trade name is literal: it kills people who are looking at something else on the ground.