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Faculty Profile
Geoffrey Williams

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Geoff Williams

Visiting Assistant Professor

Department of Environmental Biology
126 Illick Hall

[email protected]

Education

  • Ph.D. in Forestry and Natural Resources, Purdue University, 2021
    • Dissertation: Thousand Cankers Disease of Eastern Black Walnut: Ecological Interactions in the Holobiont of a Bark Beetle-Fungal Disease
  • M.S. in Natural Resources, University of Idaho, 2017
    • Thesis: Spatial Foliage Distribution Models for Western Larch (Larix occidentalis)
  • B.S. in Plant Biology, University of Michigan, 2010

Forest Pathology and Genecology Lab

The lab is seeking graduate students.

The lab works on plant health challenges affecting managed and unmanaged forests and conservation in New York State, Lake States and Northeast US, and Worldwide. The lab is currently focused on developing new research areas in oak wilt and beech leaf disease as systems to develop tools and solutions for

  1. Promoting resistance to emergent diseases across the landscape via restoration and adaptive silviculture;
  2. Providing recommendations for improving resilience to climate change and related emergent forest diseases;
  3. Identifying high risk areas and landscape/environmental contexts by building epidemiological models for both forest landscapes and urban contexts—these models can be supplemented with empirical data collected using...
  4. ...Novel monitoring approaches (combined insect-spore trapping, eDNA, nanopore sequencing)

New Research Areas and Questions (@ ESF):

  • Oak Wilt. Is there natural genetic variation in resistance, tolerance, or susceptibility to Bretziella fagacearum in Northern red oak (Quercus rubrum)? What are the vectors that transmit oak wilt in New York and the Northeast, their phenology, and relationships to environmental factors that predict their competency as vectors and risk of spread of oak wilt such as forest composition, climate, and harvesting activities?
  • Beech Leaf Disease. Is Litylenchus crenatae mccannii wind-dispersed, and if so, how does wind-dispersal compare to other passive dispersal mechanisms? How are populations and dispersal of Litylenchus crenatae mccannii affected by stand characteristics, environmental factors, and silvicultural interventions?

Ongoing Research (with partners at Michigan State University, US Forest Service, and international research institutions):

  • Urban Forest Health and Monitoring. 1) To what extent do “sentinel trees” planted outside their native range on other continents recruit insect pests and pathogens that may go on to become invasive in their native range; 2) is this more likely for exotic tree species that are widely planted and closely related to native flora; and 3) can urban forests and botanical gardens be used as resources for citizen-science based monitoring to detect emergent, potentially invasive forest diseases before they are introduced?
  • Plant Health Dimensions of Assisted Migration. Our lab conducts ongoing research on climate adaptation and forest health that takes advantage of historical provenance and progeny trials of key species (Northern red oak, Port-Orford cedar). How will local populations respond to climate change and assisted migration based on data from long-term field trials in terms of growth, survival, and impacts of insect pests and fungal pathogens?
  • Oak Decline. For over 100 years, “decline” in Northern red oak has been observed in its range in the Eastern United States, starting in Virginia, later in Pennsylvania, and more recently in areas such as Michigan and New York. The consistent pattern linking these phenomena has been a cycle starting with repeated defoliation (often by the invasive gypsy moth Lymantria dispar), followed by root rots caused by Armillaria sp. and attack by borers such as chestnut borer (Agrilus bilineatus). Are red oak trees already predisposed to decline prior to the implementation of shelterwoods, particularly on lower quality sites exposed to prior defoliations and with higher starting basal area, and when basal area was reduced by relatively larger factors? To what extent does local maladaptation, as predicted by analysis of growth, survival, and pest data from long term provenance trials of Northern red oak, also predict the prevalence of oak decline from insect and disease monitoring data and/or plot based data from shelterwoods?

Teaching

EFB 307 Principles of Genetics (Spring 2026)

EFB 439 Forest Health Monitoring (Maymester 2026)

EFB 340 Forest and Shade Tree Pathology (Fall 2026)

Podcasts (*en español)

  1. Mushroom Hour Podcast, Ep. 150. The Global Forest Health Crisis & the Sentinel Tree Network (feat. Geoffery Williams PhD). March 13, 2023. https://www.welcometomushroomhour.com/blogs/podcasts/ep-150-the-global-forest-health-crisis-the-sentinel-tree-network-feat-geoffery-williams-phd?_pos=1&_sid=611769437&_ss=r
  2. *Patagonia Forestal – Programa 59. June 15, 2022. https://podcasters.spotify.com/pod/show/patagoniaforestal/episodes/PATAGONIA-FORESTAL---Programa-59-e1jvp26

Press Releases (*en español)

  1. Williams, G.M. 2024. Forests are under attack from invasive species: International commerce and travel bring ecological destruction to the world’s most cherished natural places. We need to do more to stop the assault. Knowable Magazine, January 24, 2024. https://knowablemagazine.org/content/article/food-environment/2024/dead-and-dying-trees-invasive-species-forest-pests-diseases
  2. *Williams, G.M. 2024. Los bosques están bajo el ataque de especies invasoras: El comercio internacional y los viajes traen consigo la destrucción ecológica de los lugares naturales más preciados del mundo. February 29, 2024. es.knowablemagazine.org/content/articulo/alimentos-ambiente/2024/bosques-bajo-ataque-de-especies-invasoras

Selected Publications and Preprints

Google Scholar

  1. Williams, G., Augustinus, B., Brockerhoff, E., Christen, S. Coyle, D., Gougherty, A., Lynch, S., Sakalidis, M., Roy, K., Stallman, J., Franic, I., Ghelardini, L., Santini, A., and Sniezko, R. (In review). Biogeography filters forest phytopathogen establishment. Preprint.
  2. Esperón-Rodríguez, M., … Williams, G., et al. 2025. Urban forests are essential for climate-resilience and biodiversity: A call to policymakers. Plants, People, Planet 8(1):14-19. https://doi.org/10.1002/ppp3.70125
  3. Williams, G., Lynch, S., Sakalidis, L., Stallman, J., Roy, K., Gougherty, A., Coyle, D., Sniezko, R. 2025. An annotated registry of established forest pathogens in the continental USA, Canada, and Hawaiian Islands. NeoBiota 101 (2025): 119-134. https://doi.org/10.3897/neobiota.101.157996
  4. Williams, G. and Ginzel, M. 2025. Native and exotic Juglans nigra seedlings recruit distinct mycobiomes that differentiate with emergent disease variation. EcoSphere 16(4). doi.org/10.1002/ecs2.70253
  5. Molina L., Williams G., deErrasti A., Hadziabdic D., Pildain MB. 2025. Diversity of fungi cultured from galleries and bodies of ambrosia beetles (Gnathotrupes spp.) and carpenter moths (Chilecomadia valdiviana) in lenga (Nothofagus pumilio) forests in Patagonia. Mycologia 117(5), 818-834. doi.org/10.1080/00275514.2025.2522019
  6. Williams, G.M. and Ginzel, M.D. 2023. Functional roles of nematodes associated with the walnut twig beetle and eastern black walnut in the inland northwest. Forest Pathology 53, e12791. doi.org/10.1111/efp.12791
  7. Williams, G.M., Ma, Z., Adams, D., Cambell, F., Gandhi, K., Raffa, K., Santini, A., Lovett, G., Wingfield, M., Pildain, M. B., Ginzel, M., and ‡Bonello, E. B. 2023. The Global Forest Health Crisis: A Social Dilemma in Need of Collective Action. Annual Review of Phytopathology 61.
  8. Williams, G. M. and M. D. Ginzel. 2022. Forest and Plantation Soil Microbiomes Differ in Their Capacity to Suppress Feedback Between Geosmithia morbida and Rhizosphere Pathogens. Phytobiomes 5. https://doi.org/10.1094/PBIOMES-02-21-0014-R
  9. Williams, G. M. and M. D. Ginzel. 2021. Preference of Geosmithia morbida for Low Wood Moisture Content May Explain Historical Outbreaks of Thousand Cankers Disease and Predict Future Fate of Juglans nigra within its Native Range. Frontiers in Forests and Global Change 4. doi.org/10.3389/ffgc.2021.725066
  10. Onufrak, A.J., Williams, G.M. (co-first author), Klingeman III, W.E., Cregger, M.A., Klingeman, D.M., DeBruyn, J.M., Ginzel, M.D. and Hadziabdic, D. 2020. Regional Differences in the Structure of Juglans nigra Phytobiome Reflect Geographical Differences in Thousand Cankers Disease Severity. Phytobiomes Journal 4(4). doi.org/10.1094/PBIOMES-05-20-0044-R
  11. Williams, G. M. and Ginzel, M.D. 2019. Spatial and Climatic Factors Influence Ambrosia Beetle (Coleoptera: Curculionidae) Abundance in Intensively Managed Plantations of Eastern Black Walnut. Environmental Entomology 49(1).