Besides just looking good, planting trees provides many important environmental, economic, and energy efficiency benefits.
A man doesn’t plant a tree for himself. He plants it for posterity. — Alexander Smith

• Deciduous trees, planted on the South, Southeast, and especially Southwest of a building, shade windows, keeping the building cooler in hot weather. Shading buildings reduces air-conditioning electricity consumption, which reduces global warming caused by electricity generation. Every air conditioner owner needs the a/c running at the same time during the summer heat. Air conditioning constitutes about 60 percent of our increasing summer electrical peak load, which drives the need for new coal-fired power plants.
• Mature trees shade lawns, which then require less watering than un-shaded lawns. Less watering reduces water-pumping and therefore reduces municipal electricity consumption. Reduced watering also postpones investments in additional water-resource facilities. Ultimately we need to shade our lawns or employ xeriscaping  to reduce the huge water and electricity burden of keeping them green.
• Research indicates that trees cool whole communities by providing both shade and evaporative cooling due to the water transpiration from tree leaves. Lawrence Berkeley Laboratory (LBL) found a 3-to-6 degree temperature difference between neighborhoods with mature-tree shade and newer neighborhoods with little shade.
• Trees reduce the root cause of global warming: our rising global carbon dioxide levels by sequestering (removing and holding) carbon dioxide.
• Coniferous trees, planted to the North, Northeast, and Northwest of buildings block cold winds and reduce Winter heating costs. A South Dakota study measured 25-to-40 percent heating savings from windbreaks in windy areas.
• Trees  also increase your property value far more than their initial cost plus the water and mulch you put on them. Few other investments can provide you with as many benefits as a well-planted tree?

Lawrence Berkeley Laboratory scientists report that trees save electricity at a cost of around 1¢ per kilowatt-hour (kWh), which beats buying it at 10¢ per kWh a typical North American cost. For advice on the right trees and the right places for tree planting, contact your local nurseries, landscapers, and landscape architects. Have you planted a tree lately?