Keep mulch away from the tree's trunk. An evergreen windbreak on the north or northwest will help block cold winds in winter. Large shade trees on the southeast, southwest, and west sides of the house provide cooling shade in summer but don't obstruct the low winter sun. Shade from trees improves human comfort, reduces air conditioning costs, reduces peak electricity loads, lessening the chance of power outages. Plant trees for winter warmth.
Conifers form the best windbreaks.
Two or more rows are best if space allows, but even a single row will help. Planting trees can produce significant cash savings when they are properly used for shade and winter wind protection. Studies show that shade trees can produce savings of more than 50 percent in air conditioning use and associated energy costs. The contribution of trees in winter may not be as obvious, bust can be just as dramatic. Homes that use windbreaks can save as much as 17 percent on heating bills.