Somewhere I read that you can plant trees to help your heating and cooling system be more efficient. I can't remember all the specifics but it goes like this: Plant deciduous trees on the south side of your house, when they lose their leaves in the winter they allow the sun to hit your house, thus warming it and they shade it in the summer. Plant evergreens on the north side, they serve as a wind block in the winter and shade in the summer. I get the east and west sides confused, but you put deciduous on one side and evergreens on the other. I think it is evergreens on the west because it blocks the wind and snow in the winter and blocks heavy storms in the summer, but you get the point.