Trees offer many functional and aesthetic benefits, but one of the most common is shade. Because of this, one of the most important aspects of tree selection and planting is placement. Improper placement of trees can diminish the value of the tree on the site. The tree can actually become a liability if it conflicts with infrastructure or just does not providing any useful shade at all. For shade where it’s needed most that also allows passive solar gain in the winter months, you must use an energy efficient design.

Figure 1  (Diagram by Greg Pierceall)

In this hemisphere, the sun is in the south, and the source of cold weather is in the north. Whenever possible, place openings for sunlight and radiant heat primarily on the southern exposure, then on the west and east. For energy efficiency in winter, use the low arc of the sun to capture the maximum amount of warmth through east-, west- and south-facing windows. Windows with a northern exposure are a source of cool air from prevailing winds during the hot months, so give the north minimum exposure and maximum natural protection in the winter.

When selecting trees for energy efficiency, don’t plant evergreen trees near the house on southern exposures. Trees may provide some shade and screening but will also block out the warming effects of the sun during winter months. When choosing trees for shade and solar gain, choose larger, deciduous-canopy trees that provide an advantage year round. Select good quality trees that are suitable for your location from a reputable source. See the publication FNR-433-W on the Education Store website for more information on tree selection and planting.

Correct placement is critical for an energy-efficient design and low maintenance as the tree grows and matures. Be certain that the mature height and spread fit the location before placing the tree. This allows the tree freedom to spread into the design space naturally without excessive pruning to prevent conflicts with the house. However, the tree still must be close enough to the house for the canopy to provide shade. A good rule of thumb is to plant the tree at least 20 feet from the house. For larger shade trees, you may need to plant as far as 40 feet from the house to insure room for growth (see Figure 1).

Trees help make homes energy-efficient by creating a cooling effect during the hot summer months or by allowing the passive solar gain during cold winter months. However, proper selection and placement is critical to make this work.

Resources
Tree Installation: Process and Practices, The Education Store
Tree Planting Instructions, Indiana Department of Natural Resources
Planting & Transplanting Landscape Trees and Shrubs​, Department of Horticulture, Purdue University

Lindsey Purcell, Urban Forestry Specialist
Department of Forestry and Natural Resources, Purdue University​​