Everyone knows that summer temperatures are cooler in the shade, but trees can help cut winter energy costs, too. The most common approach is to plant evergreen trees and shrubs on the north and northwest sides of properties.
“To reduce winter heating costs, plant evergreen trees and shrubs as windbreaks,” said Tchukki Andersen, BCMA, CTSP* and staff arborist with the Tree Care Industry Association (TCIA). “Generally, most cold winds come from the north or west, so on those sides of the building plant a dense row of evergreens that maintain branches low to the ground. To provide additional insulation for your building, evergreen shrubs should be planted slightly away from the foundation.”
The ultimate goal of planting a windbreak or living snow fence is weather control. By creating a design that takes into account wind speed and direction, snow accumulation patterns and areas of high and low usage, spring and summer plantings can offer homeowners benefits ranging from reduced energy costs to more efficient water management.
“Wind barriers can channel winds away from your house and cut down on cold drafts getting into your house,” said Andersen. “In addition, shrubs, bushes and vines planted near a house can help insulate the home in winter and summer.”
Allow enough space in the tree’s root zone for roots to grow. Install physical root barriers if concerns about the foundation arise.
Whether your goal is to reduce the chilling effects of winter winds or control the accumulation of snow, the density of the plantings is key. A rough estimate of density can be determined by estimating the ratio of the “solid” area (branches, trunks, leaves, etc.) to the total area of the barrier. For example, a row of deciduous trees might offer a density of roughly 30 percent, which means that the row consists of 30 percent trees and 70 percent open space in winter. By comparison, a row of conifers might have a density of 50 percent or 60 percent in winter.
Higher density windbreaks are better at slowing wind speed enough to cause snow to drop to the ground and accumulate both on the windward and leeward side of the row (or rows). These types of living snow fences are extremely useful for keeping roads, driveways and other high-use areas clear of drifts, which means less plowing, less shoveling and less aggravation.
On the other hand, trees should not be planted on the southern sides of homes in cold climates because the branches of these trees will block some winter sun. Open blinds and drapes on the south side of your home during winter days and close them at night. Sun angles are low in winter, allowing substantial solar heating through all south windows. If there is vegetation that shades southern exposure windows, a tree care provider can determine if some of this tree growth can be pruned without harming the tree.
Remember, every location is different, and there is no perfect design that will be effective in all situations.