Emerald Ash Borer (EAB) infestation is a widespread problem in North America that has plagued ash tree populations since the beetle’s introduction into the continent in the early 2000s. The beetles bore into the vascular system of these trees, frequently resulting in the death of the ash in 5-7 years. In 2012, the first EAB infestation was reported in Great Smoky Mountains National Park (GSMNP). In this study, a modeling of the potential spread from known EAB infestation sites within GSMNP has been conducted based on the known flight range of individual EABs within their lifespan. Areas of low, intermediate, and high risk of infestation are identified by calculating a spread zone around each infestation site. The magnitude of these areas is indicative of the rather quick spread of EABs, and the potentially dire future of ash trees near infested areas in GSMNP.
11 thoughts on “Emerald Ash Borer Infestation in Great Smoky Mountains National Park”
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At this early stage in the infestation, do you think that park managers should focus search & removal efforts by working their way outwards from the currently infested trees, or might it make sense to assume the beetles have already spread through the high-risk areas, and begin removal efforts working inwards from the radii of those areas to prevent further spread outside the high-risk areas?
That is a very interesting question. It appears that due to funds and personnel, most parks are currently only treating those trees that are already showing signs of infestation (insecticides injected into the trunk or surrounding soil). But theoretically, if those funds and personnel were available, I am unsure as to how they would be best applied. Proactively treating all potential infestation sites within the spread radius would be the best approach, but unrealistic in its scope. If the tree is a truly an isolated incident, then treating at the source before the onset of the mating season would likely work. The possible distance of flight during the mating season makes me think that working inwards may not be effective, as the beetles could just bypass the outer margin of the treatment area. One possible treatment of the problem that seems promising is biological control, where parasitoid insects that kill EABs are released near infestation sites (https://www.nrs.fs.fed.us/disturbance/invasive_species/eab/control_management/biological_control/). This is undoubtedly a problem that is afflicting a wide swath of North America, so it will be interesting to see what treatment methods are used in the near future, and how effective they are.
Also, out of curiosity, are you working with any faculty in EES or Biology on this?
And no, I am not. I actually stumbled across the National Park Service’s GIS Data portal while doing research for a personal backpacking trip in GSMNP! However, I think that it is a supremely important research topic, and would be interested to see if there are has been any research/work done among faculty members relating to this problem in the Tennessee region.
I know Dr. Malu Jorge in EES was working with a student who graduated last year who was looking into ash borer infestations in Nashville Metro Parks. If you’re interested in maybe doing more research on this you should read out to her.
Oh that’s awesome! Thanks for the information!
Hi Jackson,
This is a really great project and definitely an important one that helps discuss preservation. If you had specific location data for your trees, how do you think you would have approached your project? Also, I wonder if this type of research could have also meritted a use of fuzzy logic and putting it into direct comparison with your final product. Really great project!
Hi Javier,
Thanks for your insight. I think incorporating fuzzy logic would have been a great approach, as it could have resulted in a wider spectrum of the degree of risk rather than the somewhat arbitrary low, intermediate, and high risk zones. And if specific tree data was available, I think that the first steps of the project would have remained largely the same (identifying areas of potential* spread), however there would have been some more interesting analysis to do on the backend. Perhaps, a study of the relationship between ash tree density in areas of varying degrees of infestation risk would have been conducted (which likely would have required some more sophisticated biological modeling of the movement of EABs).
Jackson, this is a great application for GIS, and your presentation is very clear and intuitive. You mention ensuring overlapping areas are not counted more than once, which is important for an accurate measure of spread areas. Are there variant measurements in which you would take the overlapping areas into account? If areas with more infestations are at greater risk, perhaps visualizing the density of nearby infestations could identify areas that are most in need of intervention.
Yes Colton, that is a very important point. Especially within the areas of high risk, I think it could be helpful to incorporate the overlapping areas into a calculus of what areas are at the most risk. Perhaps a simple sum of the number of spread areas that overlap at a given location could be used to provide a higher resolution account of the areas at risk (i.e. something such as if there are a defined number of overlaps within a high risk area, that point is deemed critical or so forth). Using the density of nearby infestations is another approach that I could see leading to a more continuous result, and perhaps an easier one to arrive at within the ArcMap platform.
Jackson–good start on a problem that has pretty minimal input data. How would you model distributions of the two vulnerable tree species? I can imagine a suitability analysis would help estimate habitat areas with likely high densities of the vulnerable trees, which would help guide mitigation efforts. If you were to collect or advise about collection of new field data on the distribution of the pests and the trees, how what would you advocate?