One of the most common challenges we’re seeing here in the Midwest is a tremendous amount of tree loss on commercial properties. In this article we’re going to be giving you some information about how trees work and what they need. If you’d like to know even more about how to save your trees, you can request a copy of the free report, “Seven strategies to save your trees” at www.tnosolutions.com.
According to the USDA Forest Service, the average lifespan of an urban tree is less than 10 years, however their potential is more than 30 years. The reason for the shorter lifespan is due to two main problems: 1) the unnatural environment in which they are put and 2) the reactionary tree-care that is standard in the industry. As explained by an article in Arbor Age Magazine, “Every tree requires a specific soil texture, nutrient complex, stand density, moisture regime, temperature range, photo period, and associate organisms (soil micro-organisms, beneficial insects, etc.) to reach its full genetic potential.” By understanding how a tree lives, defends itself and dies, you can find a way to apply proper tree care and thus enhance its health and longevity.
A Tree’s Life
Trees capture energy through their leaves in a process called photosynthesis, and they obtain water, oxygen and minerals from soil through their roots. Photosynthesis creates sugars and starches, which are the food for sustaining life and growth. Any unused food supply is stored in the tree until it is needed for breaking winter dormancy, producing leaves, reproduction, responding to wounds, etc. When the supply is deficient, growth and/or defense suffer.
A Tree’s Defense and Death
When a tree is under stress, it must use up its stored energy to survive, which means it can’t use its stored energy for typical growth patterns. The tree appears healthy even though it is suffering because the first signs of stress are within the tree or below the ground. If the stressor continues, the tree will begin showing signs of wear. For example, if the roots are not able to grow properly, the top of the tree will not receive adequate water and nutrients, and fewer, smaller, yellowish leaves are produced. If the stressor is not removed, the tree will eventually die. Following are lists of typical symptoms of stress as well as factors that contribute to the stress.
Factors that contribute to tree stress:
- Over watering
- Soil compaction/poor aeration
- Freezing/temp fluctuations
- Nutrient deficiencies
- Chemical injury
- Mechanical damage
- Transplant shock
- Improper planting depth
- Lack of root space
- Competing vegetation
- Improper pruning
Typical Symptoms of Urban Tree Stress
- Stunted growth
- Increased fruit production
- Frost cracks
- Susceptibility to infectious diseases
- Susceptibility to insects, especially borers and bark beetles
- Declining root systems
Tree Repair (Not Replacement)
Standard practice in the commercial landscape industry is to replace trees that are showing signs of stress. In fact, many properties build in the cost of replacing trees as an annual cost, but this doesn’t have to be the case. Creating and maintaining a comprehensive tree care program will help limit or even eliminate the need to replace sick and dying trees. Ideally, the program would begin prior to planting, but it must continue for the life of the tree. As explained in a leaflet from Clemson University’s Dept. of Forestry and Natural Resources, “There are three important phases in urban tree development during which practices should be modified to meet the tree’s ability to withstand change. These include the planting/establishment phase, a juvenile growth phase, and maturity.”
Tree selection is obviously an incredibly important aspect of a tree care program. Like fitting a square peg into a round hole, attempting to put a redwood into a roadway median is not a smart decision. Do research to determine if the tree’s size at maturity will fit so no altering to the root or crown system needs to be done. The health of the soil is critical the planting and juvenile growth phase because compacted or poorly drained soils affect the root system. Transplanting a tree can add major stress to the tree and often newly planted trees only last one or two years because of it. If the soil is conditioned, it will lessen the transplant shock because it will provide adequate water drainage and accessibility to oxygen.
During the juvenile growth phase, the tree is able to adapt to changes and respond to maintenance treatments. However, as a tree matures its ability to adapt decreases and, therefore, it is essential that a stable environment is created prior to the tree becoming mature.
What you can do
Regardless of the stage of your trees, you can and should set up a tree care program. Performing leaf, soil and site tests can help you to determine the underlying cause of the stress, and a specialist can help create your program.