Читать книгу Landscaping with Trees in the Midwest - Scott A. Zanon - Страница 11

Trees 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.