Arbor Day has passed, but you can still plant trees through the end of May. Trees along the Front Range have it tough, especially with our occasionally heavy spring snowfalls. Planting trees that are structurally sound and resilient will reward you down the road. Here are some tips to consider when selecting your new tree:
Fast-growing trees are weak-wooded and more susceptible to snow damage and other problems. Cottonwoods, poplars, green ash and silver maples are all fast growers that have suffered a great deal of damage in past snowstorms.
Trees with smaller leaf surfaces will shed snow more readily than those with larger leaves. Many upright junipers and arborvitae have flat foliage that catch the snow and in a heavy snowfall can cause broken branches or flared out tops.
The angle at which a branch attaches to the main trunk is important to the strength of the union. A 45-to-90-degree attachment or a U-shaped branch-trunk union is normally stronger than a lesser angle or a V-shaped branch-trunk union. This narrow angle indicates a weak union, and often the bark will split off the trunk, especially under the weight of heavy snow. Side branches that are greater than three-quarters as large as the trunk of the tree are prone to damage.
Trees with double trunks may look beautiful and full in the nursery but can be vulnerable to damage as they grow. Double trunks are normally weak and should be avoided. Co-dominant leaders (two equal-sized trunks competing to be the main leader) may develop. Should this occur, choose one and prune out the other.
Information on recommended trees to plant for the Front Range can be found in Colorado State University Cooperative Extension fact sheets 7.419 and 7.418. Find them online at www.ext.colostate.edu, or call the CSU Cooperative Extension office in your county.
Lynda Gerber is a Colorado State University Cooperative Extension master gardener in Arapahoe County.
