There are many dangers to your home. Sometimes it might seem like there are too many things to think about. Fires, heavy rain, winds and other natural events can lead to expensive repairs or even a complete destruction of your home.
Defensible space is a concept that is designed to minimize the risk to your home from such events. The basic idea is to define 3 zones around your home; one that reaches 15 feet in all directions from your home, a second one that goes from 15 to between 75 and 125 feet out and a third that goes from the end of zone 2 to the end of your property.
In zone 1 you should eliminate anything flammable, including bushes, firewood, and trees. In zone 2 you can have some bushes and trees, but preferably spread out. Leaves and branches on the ground should be kept under control. Zone 3 is not as restrictive, but vegetation should still be kept in check.
Using this approach, you will minimize the risk of catastrophic damage to your home.