Co-Principal Investigator(s):

NICHOLAS FISICHELLI, Schoodic Institute at Acadia National Park, ME

NICOLE ROGERS, University of Maine

YONGJIANG ZHANG, University of Maine

Abstract: Climate change increases the likelihood of extreme climate events that impact trees in both summer and winter. However, it is unclear how forest managers should plan for the impacts of extreme climate events that significantly impact forest structure and composition. NSRC researchers will determine how tree regeneration in the Northern Forest will respond to extreme drought, heat, and midwinter warming events to better inform forest management.

Researchers will conduct two experiments that simulate future extreme climate conditions using saplings of ten Northern Forest tree species. First, they will determine survival, growth, and physiological adaptations of trees to drought and heat stress at experimental locations across a climate gradient representative of the Northern Forest region. Second, they will quantify the phenological sensitivity of Northern Forest trees to extreme midwinter warming events of different magnitudes. With these results, they will identify forest tree species that are best and least adapted to future extreme climate events and the physiological characteristics that promote resistance and resilience to extreme climate change.

Researchers will collaborate with forest landowner partners at six locations in Maine and engage a broad scope of stakeholders. They will engage students and community members in hands-on tree physiological measurements, provide fact sheets and guided tours for landowners to discuss how research results can be used in forest management planning, present results at regional forestry conferences, incorporate findings into the Forests of Maine Teachers’ Tours with the Maine TREE foundation, and disseminate project findings through an informational video about how trees respond to climate change to distribute across the Northern Forest region.

Final Products

Pinover, L., Butnor, J.R., Fisichelli, N., Murakamib, P., Rogers, N., Zhang, Y.J., and Wason, J. Earlier leaf out and loss of cold tolerance for northeastern U.S. trees in response to winter warming events and early springs. In advanced stages of preparation for submission in early 2026. 

Pinover, L., Mrenna, B., Fisichelli, N., Rogers, N., Zhang, Y.J., and Wason, J. Higher risk of mortality for tree regeneration at warm range margins during compounded heat and drought. In advanced stages of preparation for submission in early 2026.

Mrenna. B., Pinover, L., Fisichelli, N., Rogers, N., Zhang Y.J., and Wason, J. “Future Forests: Heat and Drought Impacts on Tree Regeneration in Maine” 2-page outreach document for landowners. 

Pinover, Laura, “Impacts of Extreme Climate Events on Tree Regeneration in the Northern Forest” (2025).  M.S. Thesis. Electronic Theses and Dissertations. 4233. https://digitalcommons.library.umaine.edu/etd/4233 

Mrenna, Brigid, “Testing How Plant Traits Predict Survival of Northeastern U.S. Tree Seedlings Under Compounded Heat and Drought Stress” (2025). Undergraduate Honors Thesis. 

LaCasse, Casandra, “Phenological Response of Northeastern Tree Species to Midwinter Warming Events” (2024). Undergraduate Capstone Project. 

Presentations

Pinover L, Butnor J, Murakami P, Rogers N, Zhang Y, and Wason J. (2024). Impacts of early springs and winter warming events on spring phenology and cold tolerance among temperate and boreal tree species [Oral Presentation]. Forest Ecosystem Monitoring Cooperative Annual Meeting. Burlington, Vermont (December). 

Mrenna B, Pinover L, Fisichelli N, Rogers N, Zhang Y, and Wason J. (2025). How do plant traits relate to the survival of tree seedlings under compounded heat and drought stress? [Poster Presentation]. University of Maine Annual Student Symposium. Orono, Maine (April). Awarded Dr. Susan J. Hunter Presidential Research Impact Award.