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What about my trees?

What about my trees?

By Thad Rhodes, District Forester
Kansas Forest Service
Manhattan, Kansas

With the dry weather that we have been experiencing over the past two years, a lot of people are wondering how their trees are faring. Much like other vegetation, these plants are under a considerable amount of stress. Many people think that their mature trees will survive since the roots are deep enough to extend into the water table. While this may be true for certain locations, it is generally not the case, as the majority of a tree’s root system is fairly shallow (within the top 24” of the soil) due to the need for oxygen exchange by the roots. Taking this into consideration, it is understandable that this portion of the soil profile is also the most prone to desiccation and competition from other vegetation.

Tree Stress

Once a tree is stressed, it will become more susceptible to insect and disease problems. A considerable number of these damaging agents are opportunistic, targeting trees that are not growing as vigorously as they should. During periods of stress, these problems can become more prevalent and increase in number and extent. A good example of this is the extensive pine mortality that is being experienced in the Rocky Mountain region from the Mountain Pine Beetleā€”a native insect that has reached epidemic levels because of conditions such as overcrowded older trees and periods of warmer, drier weather. Overall, healthy trees are better positioned to ward off these types of attacks and survive until conditions return to “normal.”

However, young trees are not immune either. Adequate moisture is certainly important to immature trees during the growing season, but entering the dormant season without sufficient resources will leave them more susceptible to environmental issues such as sunscald, decline, and winter desiccation. Some of these issues can even lead to additional problems in the future, reiterating the expression that “an ounce of prevention is worth a pound of cure.”

What can be done to help your trees?

Ideally, provide supplemental watering if possible. A slow, soaking watering will help to ensure that an adequate amount of moisture reaches the root system. Soaker hoses, buckets with holes in the bottom, or turning the hose on at a slow trickle are all possible options for landscape trees. In a larger planting such as windbreaks, supplemental watering might not be an option, so controlling competing vegetation may be the best bet. Smooth brome is notorious for competing for moisture in tree plantings and usually comes out winning. Trying to control this “green death” will free up a considerable amount of moisture for the other plants. In a forested setting, options exist for performing Timber Stand Improvement to cull out some of the competing trees to release resources for the more desirable species (usually the oaks and walnuts), as well as to encourage future regeneration. Limiting livestock access to certain areas will also help because of the soil compaction and root damage that can be caused. Through proper management of these sites, you can help to ensure that desirable species will continue to be a part of the woodland for years to come.

Regardless of your approach, it is important to remember that it has taken an extended period for the trees to get to this point and is probably not something that can be corrected overnight. By taking the time to put forth a little effort now, you will be in a better position for a quicker rebound and fewer problems in the future.

To learn more about trees, please contact your local NRCS office or conservation district office located at your local county USDA Service Center (listed in the telephone book under United States Government or on the internet at offices.usda.gov). More information is also available about NRCS on the Kansas Web site at www.ks.nrcs.usda.gov. Follow us on Twitter @NRCS_Kansas. USDA is an equal opportunity provider and employer.