Keep trees on your property.

HealthyHouse^TM TechTip

Think twice about removing trees on your property. When trees are between your house and a source of EMF radiation they will help to reduce it. In particular, trees can reduce all types of wireless RF (radio-frequency) radiation. Trees can also help to block the electric fields originating from overhead powerlines. There are many variables that will influence how well the radiation is reduced like size of the tree, position, and density.