Kind of an odd flex given how walkable San Francisco is, but the "risk adversity" is because people actually die. Last year, five people died from fallen trees in a single storm (two in the city).
An interesting question is: Have people trees because is rich, or they are richer because they had trees? (and this will save a lot of money each year on energy bills, food and even psychologists). Trees are a tool to fight poverty. The problem is how to made the poor people respect them.