Compared to other everyday risks we readily accept, the overall risk to us from branches or trees falling is extremely low.

Our annual risk of being killed or seriously injured is less than one in a million. That's so low, we're at greater risk driving on about a 400km/250mi round trip to visit friends for a weekend than from branches or trees falling over an entire year. 

Driving for about 400km/250mi = 1 micromort, which is a one in a million chance of dying.

Given the number of trees we live with, and how many millions of us pass them daily, being killed or injured by a tree is a rare event. A rare event that usually happens during severe weather.