Toomer's Corner Oaks Task Force methods and offers of assistance, Feb. 28, 2011

Oaks Update, Feb. 24, 2011Several individuals and groups have contacted Auburn University and offered their ideas, time, and services to help save Toomer's Corner Oaks.  We greatly appreciate these offers; however, it is not possible to respond to every inquiry or offer of help due to the nature of the problem and the rapid pace of the on-going response.  The university has assembled a task force composed primarily of Auburn faculty with expertise covering all aspects of the response. 

With respect to potential soil and groundwater contamination by the herbicide: Faculty from the Civil Engineering Department (Environmental Science Group) and the Agronomy and Soils Department, in collaboration with Auburn University, private environmental firms and state regulatory staff, have developed and are implementing a strategy for assessing the magnitude and distribution of contaminants related to the herbicide Spike 80DF in soil and groundwater.

With regards to using nutritional Supplements, fertilizers, or other growth stimulants to help save the trees: An important factor in tree health is that they have moisture, nutrients and carbohydrates available for leaf and twig growth. When nutrients are present in the soil, trees respond by actively growing new root tips and translocating nutrients and water from the soil to the leaves.  Unfortunately, the herbicide used to poison the trees is water soluble and is easily taken up by the roots.  Once into the xylem the herbicide is transported to the leaves where the compound interferes with photosynthesis and destroys the chlorophyll and cell membranes. In contrast to favorable growing conditions, when trees are under stress they compensate by shutting down transpiration, and the translocation of water and nutrients from the soil.  Therefore, to limit the movement of herbicide to the leaves and the effects of the herbicide on new tissue growth, the use of nutrients or carbohydrates to "feed" the Toomer's Corner Oaks was not considered a good option at this time.

With regards to using biostimulants to enhance microbial degradation of the herbicide: While this technique has been successfully used for remediation of certain soil contaminants, it has not been demonstrated to be effective for tebuthiuron degradation within conditions similar to the Toomer's Corner Oaks poisoning. Tebuthiuron is extremely persistent in the soil. Although microbial degradation of tebuthiuron can occur in soil, it is not considered to be the dominant mechanism of dissipation in temperate climates. Since microorganisms around the tree roots have no prior exposure to tebuthiuron, microbial degradation, even with application of biostimulants, is not likely to occur fast enough to bring tebuthiuron concentrations down to a non-toxic level within a short period of time. Despite the costs, excavation of soil is the most rapid and effective way for removing high concentrations of tebuthiuron.

Last Updated: Apr. 9, 2012

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