Trees can be energy efficient in many ways. let me explain using a list.
1.Plant trees next to south and west facing windows. That way the shade lowers your cooling costs.
2. Place leafy shade trees to the south and west and plant evergreens towards the north.
3. Try to plant trees closer together instead of spread out to save on water.
4. Intead of watering your trees once a week with a large amount of water try using a small amount each day.
5. Don't plant trees too close to sprinkler systems because it will risk damaging them.