Landscaping with Trees in the Midwest. Scott A. Zanon
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versus Turf
(an ongoing problem)
S HOULD ONE PLANT trees or turf? This age-old battle continues to be waged. Trees and grasses do not naturally coexist. Grasses do not grow in the forests and trees do not flourish in the prairies. However, with some common sense and knowledge, they can peacefully coexist.
Although trees and turfgrass are both effective landscape plants, each has different needs concerning growing conditions, light and nutrition requirements, and moisture levels. Problems occur when the care of trees and turf are not separated. Management requirements of each tend to compromise the other. But, ecological tree removal often clashes with political and emotional issues. People in general do not like to cut down trees.
Property owners across the country are beginning to pay attention to the turfgrass they so lovingly care for. One of the main culprits of poor turf growth is too much shade. Consequently many larger, older trees are being thinned, limbed-up, or simply removed.
Shade causes poor turfgrass performance beneath trees by reducing turf quality and quantity. Grass growing under a shade tree is usually weak, thin, and subject to weed invasion for several reasons. Light quality is the crucial issue. The green tree leaves filter the critical light wavelengths for photosynthesis. As a consequence, turfgrass receives a smaller quantity and a poorer quality of light.
Shade creates other major stress factors. Reduced airflow and increased humidity levels may contribute to disease issues. An increase of air movement usually results in a decrease of diseases. Tree roots compete with grass for both water and nutrients. While this root competition can promote stress, lack of light remains the primary problem.
Morning shade has a great negative impact on turfgrass. Trees on the east and southeast sides of properties create this morning shade. Grass planted in these areas does not receive the benefit of early morning sunlight and, additionally, dew does not evaporate quickly, thus extending cooler leaf and soil temperatures. Eliminate the morning shade issue by limbing-up, thinning, or by removing the entire tree. Trees that block morning sunlight must be considered for removal as morning sun is more valuable than afternoon sun, So take heed.
Despite their differences, turf and trees can peacefully coexist and even thrive together. Achieving that balance can be attained. Armed with an understanding of how each affects the other, decisions can be reached regarding methods to modify the environment and maintenance procedures that will optimize the growing conditions for both. But good planning and proper tree selection are crucial.
Why Plant Trees?
GREAT QUESTION, isn’t it? It is difficult to grow grass under them; they are the recipient of most of the water and sunlight; their branching obstructs natural lines of sight and play. Yet, with all of these problems, the mere mention or sound of a chainsaw elicits trepidation and panic. Most human beings are tree-huggers by nature; we tend to become emotionally attached to our trees.
Imagine a park, street, or yard without a tree. What a lonely expanse of nothingness that would be. Trees are integral components of landscapes. They add grace and inspiration as well as architectural beauty. Trees have a practical side, too: they can help a home be more energy efficient by providing shade, reflecting heat, and blocking cold winter winds.
While problems tend to surface with mature trees, all trees have their good and bad points. It is rare to find a tree that will make its owner happy over its lifespan. But today, caretakers of public properties and homeowners have the option to make decisions and actions about removing trees when they want. For far too long, we gave little financial or planning consideration to trees. But when tree plantings overshadow the care of turfgrass, a slow, downward, agronomic spiral begins.
With so many trees now being removed because of structural issues, diseases, or insect infestations, or just by choice, the ability and opportunity to replant a property is afforded. Better consideration can be used when locating the trees and in selecting more suitable trees, ones that will help in the growth of turfgrass and beautify the property.
Reducing competition among trees and selecting more desirable specimens or functional trees is a wonderful gift for others to appreciate in the future. But there are many reasons for planting trees; it is important to have a specific purpose in mind. Overplanting is a costly error that affects future budgets. Focus on quality, not quantity.
Since trees are a major element of North American landscapes, we must learn more about their care, form, and function. It is also imperative to maintain tree species diversity in case of catastrophic diseases, like Dutch elm disease, or infestations of insects, such as the emerald ash borer.
Climate change is occurring due to daily human activities that emit exorbitant quantities of greenhouse gases (carbon dioxide emissions) into the global atmosphere. Trees are a tremendous biological means of sequestering carbon (CO2), thereby helping to offset fossil fuel emissions. They store carbon and are known as nature’s “carbon sinks.” So planting trees helps the environment, too.
When planting a tree, enjoy its present but cherish it in its posterity. A tree can quickly outgrow its original purpose or it can slowly grow into its intended one.
Selecting Trees
WHEN SELECTING TREES to plant, moderation and common sense have to meet. Choose varieties that will not negatively impact property lines and power lines when fully mature. Very simply: do the math. Find out what the tree’s mature size (height and width) will be and work backwards. Remember not to plant on the east or southeast sites where shade from the tree will ultimately cause problems. Before digging, be sure to contact your local utility company to mark gas lines, water pipes, or underground cables. The wrong tree species in the wrong location is a recipe for disaster. Future tree removal is problematic and expensive.
When purchasing new trees, disregard the end-of-the-season closeout offerings from local nurseries. There usually is a reason no one else purchased these leftover trees: a poor condition, a deformed shape, an ultra-common type, or a species not hardy to the area. Making that extra effort to purchase and plant high-quality, desirable trees for a location will benefit all involved immensely. Select the tree based on your criteria and use the plant usage guides in this book to recommend viable options for you.
Form and habit should be considered before making a decision for your property or garden. Architectural structure is important, especially during the winter months. Trees exhibiting an interesting shape or outline may still be appreciated when other plants are either dormant or dead. They may have weeping, arching, or sculpted branching. They may have dramatic or rounded canopies. They may be vase-shaped, pyramidal, or cascading. The appealing characteristic simply may be the massive trunk of the tree.
When selecting a tree to plant, habit is a wonderful characteristic to consider before making a decision. It is great to have all of the ornamental features, but a tree with appealing form and structure is appreciated throughout all four seasons; such a tree usually improves with age.
When properly selected, planted, and maintained, trees can add a needed dimension architecturally. Great properties and gardens have reputations for their tree plantings. But, comprehensive programs designed to care for existing trees and to plan properly for new plantings as they become necessary are vital.
Selective Pruning and Shade Seeding
VARYING AMOUNTS OF tree work are ongoing on practically every property, yet the removal and pruning of trees remains an emotional issue. Therefore, to avoid the inevitable backlash such emotions raise, the best time to do selective pruning or tree removal is in the winter or, for public grounds, during off-season.
Selective pruning, when care is taken not to ruin the shape of a tree or a shrub, will allow most trees to remain on-site and help to allow enough sunlight to filter through canopies for good turfgrass growth. Selective pruning also increases air circulation, thereby generally decreasing excess humidity and disease problems.
Selective thinning will allow some light through. A great rule of thumb is to remove no more than one-quarter of a tree’s foliage crown in a single pruning. Limbing-up of trees