National Arbor Day is celebrated to recognize the value and benefits of trees to our communities. Trees provide shade, purify air and water, manage soil erosion and improving our quality of life. Arbor Day is traditionally celebrated by planting trees. To maximize the benefits a new tree can provide, it is important to match tree species to the best possible planting site.
Location, Location, Location
Trees should not be placed randomly throughout the landscape but set with purpose and intent. Careful site selection ensures long-term health of the tree as well as safety within the landscape. Get to know the conditions at the planting site including light intensity, soil moisture and soil type. These factors will direct species selection. It is always easier to select a tree that matches the existing site conditions rather than trying to alter site conditions.
When planning for a new tree it is critical to think in terms of the ultimate mature size of the tree, not the size at planting. By planning for the mature size we can avoid the problem of a tree outgrowing its location. Likewise, considering the amount of shade the tree will provide in the future helps us avoid unexpected problems such as shading existing vegetable or flower gardens. Also consider mature tree size in relation to neighboring properties.
Trees grow to very large sizes, both above ground and below, and we need to consider the space available in both these locations when placing a tree. Problems commonly occur around utility lines, building foundations, and paved surfaces. Avoid unnecessary damage to both trees and structures by properly siting trees with respect to existing landscape elements.
Overhead Utility Lines
The ultimate mature height and spread of a tree must fit within the available growing space beneath and alongside overhead lines. We have all seen the butchered silhouettes of trees planted too close to utility lines. Avoid this with the following guidelines to site trees appropriately around overhead lines.
- Small trees: mature height 25 feet or less – allow 20 feet from overhead lines
- Medium-sized trees: mature height 30-50 feet – plant at least 35 feet from lines
- Large trees: maturing over 50 feet – minimum spacing from overhead lines is 45 feet
Call your local utility company to mark water lines, gas lines, cables, and other underground utilities. Do not plant a tree within ten feet of underground utility lines. Also pay attention to irrigation lines when digging.
A tree’s roots can extend two- to three-times beyond the canopy width. Ensure plenty of underground space for roots to develop by setting trees at a minimum distance from the building that is equal to or greater than half of the tree’s mature width. For a small tree such as a flowering plum, a distance of 10-15 feet from the foundation is adequate while large shade trees require 25 feet or more. When placing trees near the house, avoid blocking windows or desirable views.
Nobody wants their paved sidewalk or patio to buckle above the spread of a tree’s roots. To avoid problems, leave a minimum of 3 feet, but preferable 5 feet free of obstacles on all sides of the tree. Also consider the spread of the tree canopy when planting near roadways. Avoid blocking traffic signs or views around corners.
Trees perform invaluable services to the environment and are a major component of structure in the landscape. Taking time to properly select and site trees will promote health and longevity, while protecting their visual integrity.