Dr. David R. Coyle
Postdoc - Forest Health Outreach
Southern Regional Extension Forestry
University of Georgia, Athens, GA 30602
Email: drcoyle@uga.edu or dcoyle@sref.info
Twitter: @drdavecoyle
Outreach Interests:
Developing a regional forest health and invasive species outreach and education program. I will create a template and materials for extension education for southern pine health, primarily focusing on pine stand management to mitigate potential insect and disease issues, as well as for several non-native species, including (but not limited to) emerald ash borer, hemlock woolly adelgid, redbay ambrosia beetle, gypsy moth, thousand cankers disease, laurel wilt, sirex woodwasp, Chinese privet, and cogongrass. Our target audience will encompass both rural and urban communities, including “absentee” landowners and underserved and underprivileged populations. This project will integrate workshops, town hall-type meetings, traditional publications and hardcopy material, and new technologies (including webinars, social media, and other eLearning materials) in order to reach a wide range of audience. Working with the Southern Regional Extension Forestry group (
www.sref.info) will facilitate the efficient compilition and dissemination of necessary information. The goal is to create materials and curriculum that can be used across Region 8, and to ensure consistent education among state and local extension agents with regard to pine health, non-native species ecology, and forest pest management in the southeastern U.S.
Research Interests:
1. Factors affecting forest health. Tree health is affected by many factors, including soil quality and characteristics, slope, aspect, water and nutrient availability, competing vegetation, non-native species, stand density, and insects and fungi. Often, several of these factors act together - either concurrently or sequentially - and contribute to reductions in tree health. As part of a large interdisciplinary team comprised of entomologists, pathologists, soil scientists, foresters, forest health specialists, and social scientists, from the University of Georgia, the USDA Forest Serivice, and state agencies, we are investigating factors related to pine health in the Piedmont and Coastal Plain regions of Georgia and Alabama. In addition to determining fine-scale abiotic influences on tree health, interactions between fungal-vectoring insects and fungi and their attractants, we are examining landowner perceptions and behavior related to pine management. Our goal is to relate tree growth to various abiotic and biotic factors, and be able to make management recommendations to landowners.
2. Belowground-aboveground interactions. Rhizophagy and folivory have very different effects on tree growth, allometry, and physiology, as well as the relative attractiveness of a tree to other herbivores. Often, stressed trees are attacked first by root-feeding insects and their associated fungi, which can weaken the tree and predispose it to aboveground herbivory. I am investigating factors that attract root-feeding
Hylastes spp.,
Hylobius spp., and
Pachylobius spp. beetles to pine trees, and the relationship between aboveground tree condition and susceptibilty to these herbivores. Examining the effects of water stress on these interactions is an area I would like to explore, as is the relative contribution of insects (below and aboveground) to the carbon (C) cycle. Currently, most models of C dynamics either do not include insect activity, or use artificially-girdled trees as a surrogate for insect mortality. Along with a tree physiologist (
Dr. Doug Aubrey,
University of Georgia -
Savannah River Ecology Lab) and biogeochemist (
Dr. Kim Novick,
Indiana University) we have proposed to conduct a controlled field study to determine the influence of insects on tree C cycling and budgets.
3. Stand management as a method to improve health. The Southern Pine Beetle Prevention and Restoration Program has been successful in assisting land owners with changing stand structure to reduce susceptibility to SPB. However, we don't know exactly what level of management is optimal for reducing susceptibility to tree-killing insects. Evidence suggests that thinned stands are less susceptible to outbreaking insects such as SPB and the Sirex woodwasp. I am interested in different ways to use various silvicultural regimes to prevent pest outbreaks.
4. Effects of non-native species on community diversity. It has long been stated that non-natives (aka exotics, invasives) have detrimental effects on naive communities, and this relationship has been shown for many plant species. However, these relationships are less well-known for arthropods. I am in the preliminary stages of this work, and am examining data sets at the local, regional, and national level to determine the effects of non-natives on community diversity.
Education and Experience
Ph.D., 2011.
University of Wisconsin, Madison, WI. Major: Entomology. Dissertation research examined the ecology and impact of root feeding weevils (Coleoptera: Curculionidae) on sugar maple seedling growth in a northern hardwood forest.
Dr. Kenneth F. Raffa, advisor. Co-Advised by Dr. William J. Mattson, Jr., USDA Forest Service.
M.S., 2000.
Iowa State University, Ames, IA. Co-Majors: Entomology and Forestry. Thesis research examined cottonwood leaf beetle,
Chrysomela scripta (Coleoptera: Chrysomelidae), larval performance on poplar clones and the effect of larval defoliation on foliar phagostimulants in intensively-managed
Populus plantations.
Dr. Elwood R. Hart and
Dr. Richard B. Hall, advisors.
B.A., 1997.
Luther College, Decorah, IA. Major: Biology. Senior research project tested the relative efficacy of four baits for carrion beetle (Coleoptera: Silphidae) sampling.
Dr. Kirk J. Larsen, advisor.
Research Description
Current Research: I am a forest ecologist that examines abiotic and biotic factors and their impacts on forest health and functioning. Currently, I am working on factors that affect pine health issues in southeastern pine forests. Some areas in the region are experiencing pine dieback, but as of yet the reasons behind this phenomenon are unclear. As part of an interdisciplinary team comprised of University, State, and Federal personnel, I am examining soil characteristics, insects, and fungi, and combining these data with tree growth and stand history to determine the root cause of pine health issues. In collaboration with Ms. Christiane Helbig, an International Scholar from Germany, I am investigating the biology of several species of root weevils, and looking at the role they play in fungal vectoring and pine health. I am also leading a survey to examine landowner and manager knowledge and perceptions of pine health issues so that we can better focus our educational efforts.
I am also interested in the ecological effects of non-native species, and their impacts on native insect communities. In collaboration with Dr. Louise Loudermilk (USDA Forest Service) we recently showed that a very high proportion of non-native individuals in a managed hardwood forest occur – much higher than would be expected. Further, examining several different insect taxa, our data show that as the proportion of non-native individuals in a community increases, the diversity of that community decreases. I am still actively working in this area to determine the ecological ramifications of non-native species in forest communities.
Previous Research: Optimizing forest production via water and nutrient amendments. A 55 acre research plantation containing eastern cottonwood, sweetgum, sycamore, and loblolly pine was established in spring 2000 (Coleman et al. 2004) at the Savannah River Site near Aiken, SC, for the purpose of determing the effects of resource amendments (fertization and irrigation) on tree growth, biomass, and nutrient partitioning. Results from eastern cottonwood and sycamore (Coyle and Coleman 2005) and sweetgum and loblolly pine (Coyle et al. 2008) showed that fertilization was the primary driver of growth. We have completed a complete above and belowground nutrient budget through year 4 (Aubrey et al. 2012), as well as determined the optimal level of nutrient amendments for each of these species (Coyle et al. 2013). The final whole tree destructive harvests and nutrient analyses were recently completed, and we will be evaluating full-rotation growth, biomass and nutrient allocation, and nutrient budgets of these tree species.
Investigating a scale/pathogen complex related to white pine dieback in the Southern Appalachians. White pine is an economically and ecologically important tree species throughout eastern North America. Recently, increased mortality of seedlings, saplings, and mature trees has been observed in the Appalachian Mountains. A scale insect was discovered, and through molecular and taxonomic identification we have determined that this species appears to be new to the southern Appalachians. We are investigating its affect on tree survival and canker formation, as well as interactions between the scale and several fungi. This work is in collaboration with Ms. Ashley Schultz (former M.S. student in the Gandhi lab), Dr. Chris Asaro (USDA Forest Service), and several personnel from the USDA Forest Service.
Landscape-level stand management tactics to control southern pine beetle (SPB). SPB is the single most destructive forest pest in the southeastern U.S. In collaboration with University, State, and Federal personnel I have evaluated stands across the southeastern U.S. that had undergone various types of thinning, prescribed burns, and longleaf pine replants, and recording several parameters related to stand structure in an effort to mitigate the detrimental effects of SPB outbreaks. Our recent paper (Nowak et al. 2015) showed that area-wide management can greatly reduce forest susceptibility to SPB outbreaks.
Dissertation Research: A suite of invasive weevils (Coleoptera: Curculionidae) is established in the northern Great Lakes region (Coyle et al. 2008). Using field and laboratory experiments, I evaluated the effects of root weevil feeding on tree health and growth in the northern hardwood ecosystem. Phyllobius oblongus feeds primarily on sugar maple, Acer saccharum; populations are heavy in northern Wisconsin and the Upper Peninsula of Michigan. Beginning in 2005, adult and larval densities were manipulated yearly in the field using weevil amendments and pesticide treatments. Sugar maple seedling health, aboveground and belowground growth, and community dynamics were recorded using minirhizotrons and traditional tree growth monitoring methodology. Annual destructive harvests were used to determine if root herbivory affected biomass and nutrient partitioning. Adult weevil phenology and host preference and performance were monitored. I monitored the effects of larval herbivory on microbe populations and biomass using phospholipid fatty acid analysis (PLFA), and investigated larval weevil overwintering physiology.
Mentoring. I have mentored students ranging from high school to PhD candidates on all aspects of forest health research. Several of my mentees have gone on to attain advanced degrees (or gone to college, in the case of the high school student). So far, research with undergraduate mentees has resulted in two peer-reviewed publications, and several more are planned based on work currently ongoing.
Publications
Coyle, D.R. and K.J.K. Gandhi. 2014.
Plantation forests. Vol. 1, p. 138-142.
In: Biomes and Ecosystems: An Encyclopedia. R.W. Howarth (ed.). Salem Press, Pasadena, CA. 208 p.
Refereed Journal Articles:
Zalesny, R.S. Jr., J.A. Stanturf, E.S. Gardiner, G.S. Bañuelos, R.A. Hallett, A. Hass, C.M. Stange, J.H. Perdue, T.M. Young, D.R. Coyle, and W.L. Headlee. 2016.
Environmental technologies of woody crop production systems. Bioenerg. Res. 9: 492-506.
Balser, T.C., K.D. McMahon, D. Bart, D. Bronson, D.R. Coyle, N. Craig, M. Flores-Mangual, K. Forshay, S.E. Jones, A.E. Kent, and A.L. Shade. 2006.
Bridging the gap between micro- and macro-scale perspectives on the role of microbial communities in global change ecology.Plant and Soil 289: 59-70.
Coleman M.D., D.R. Coyle, J. Blake, K. Britton, M. Buford, B. Campbell, J. Cox, B. Cregg, D. Daniels, M. Jacobson, K. Johnson, T. McDonald, K. McLeod, E. Nelson, D. Robison, R. Rummer, P. Sanchez, J. Stanturf, B. Stokes, C. Trettin, J. Tuskan, L. Wright, and S. Wullschleger. 2004.
Production of Short Rotation Woody Crops Grown with a Range of Nutrient and Water Availability: Establishment Report and First-Year Responses. USDA-Forest Service, Southern Research Station, Asheville, NC. SRS-GTR-072. 21 p.
Coyle, D.R. and D.R. Lewis. 1999. Common Butterflies of Iowa. Iowa State University Extension Press, Pm 1795. 16 pp.
In Review/Accepted:
Denham, S.O., D.R Coyle, A.C. Oishi, B.P. Bullock, K. Heliövaara, and K.A. Novick. In Review. Effects of simulated, micro-infestations of bark beetles on tree resin dynamics. Forest Ecology and Management.
In the works:
Coyle, D.R, J.H. Campbell, C.E. Cunard, A.H. Joslin, A. Mundepi, U.J. Nagedra, C.A. Phillips, and M.A. Callaham. Effects of natural and anthropogenic disturbances on soil biota. To be submitted to Soil Biology and Biochemistry.
Coyle, D.R., D.P. Aubrey, and M.D. Coleman. Nitrogen dynamics of four intensively-managed tree species receiving water and nutrient amendments over a full harvest rotation. To be submitted to Forest Ecology and Management.
Coyle, D.R., J.L.M. Gutknecht, and K.F. Raffa. Altered soil microbial communities as a result of an above-belowground pest and disease progression in red pine plantations. To be submitted to Soil Biology and Biochemistry.
Coyle, D.R., J.L.M. Gutknecht, T.C. Balser, and K.F. Raffa. In Preparation. The soil microbial community of a northern hardwood forest is altered by the abundance of rhizophagous weevil larvae. To be submitted to Soil Biology and Biochemistry.
Spaine, P., M.M. Cram, D.R. Coyle, S.V. Lumpkin, and M.D. Coleman. Differential pathegenicity of Botryosphaeria species to intensively managed sweetgum, Liquidambar styraciflua. To be submitted to Tree Planter's Notes.
For further details log on website :
http://davidcoyle.uga.edu/
