Speaker: Khanh Tan

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Bio: Khanh is a graduate student in the Ecohydrology Lab at the University of New Hampshire (UNH) with research interests in forest ecology, terrestrial biogeochemistry, and remote sensing. Prior to this, she earned a BS in Environmental Sciences from Rhodes College. Her current work at UNH looks at how prescribed burns can help regenerate Northern red oak in its northward expansion due to changing conditions.

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Webinar: Northern red oak is predicted to expand its range northward in the northeastern United States as conditions continue to become more favorable and could greatly improve forest resilience by expanding the functional diversity of its new habitats. However, red oak regeneration currently faces many challenges including seed and seedling predation, pathogens, and consequences of forest mesophication such as light insufficiency and competition with more mesic species. The latter challenges are potentially caused by the absence of fire in forested landscapes since the early 1900s. Therefore, prescribed burns may help address these challenges and hence promote oak establishment and recruitment near its northern range limit. We studied six prescribed burn/unburn pairs of stands from across the White Mountain National Forest in New Hampshire, most of which were managed over the past decade, plus one unmanaged stand where a wildfire occurred. In summers 2023 and 2024, we surveyed naturally regenerated oak seedlings along transects representing gradients of burn intensity, distance from edge, overstory density, and soil disturbance. We expect greater seedling survival and growth on burned sites, along with higher nutrient availability and lower pathogen loads. This research aims to provide landowners and forest managers in the northeast with tangible and actionable information on prescribed burning that can facilitate the implementation of improved management practices. In turn, increasing oak regeneration will result in more diverse and climate-ready forests and continue providing a wide range of ecosystem services.