Effects of browsing by white-tailed deer on tree regeneration vary by ontogeny and palatability in forests of the northeastern USA

Abstract

Tree regeneration in northern temperate and southern boreal forests is threatened by multiple factors, including over-browsing by ungulates such as white-tailed deer (Odocoileus virginiana). However, characterizing the effects of deer browse on tree regeneration at regional scales has been challenging due to (a) the lack of reliable indicators of browsing intensity and (b) the fact that browsing impacts are likely to vary by seedling size yet coarse metrics are often used to capture this seedling attribute. To address these challenges, we modeled effects of white-tailed deer browse and other biotic and abiotic factors on tree seedlings of different sizes for 12 common species across the northeastern USA by leveraging the Forest Inventory and Analysis (FIA) program’s Regeneration Indicator (RI) dataset, which assesses seedling abundance across six height classes. We developed four potential proxies for deer browse intensity, including town-level harvest records, and compared these with field-estimated browse intensity. Highly palatable species experienced moderate to strong negative browse impacts, especially for medium to large seedling sizes, while less palatable species either showed no impact or experienced modest benefits. Acer saccharum displayed the strongest negative relationships with browsing intensity and was also affected at smaller size classes than other species, whereas impacts on Acer rubrum and Betula alleghaniensis were limited to one larger (≥ 0.9 m tall) seedling size class. Collectively, these results underscore the pervasive impacts of deer browse on regeneration dynamics in northeastern forests and the opportunities for adaptive strategies to recruit species beyond vulnerable size classes.

Citation

​Harris, Lucas B.; Pastore, Melissa A.; D’Amato, Anthony W. 2025. Effects of browsing by white-tailed deer on tree regeneration vary by ontogeny and palatability in forests of the northeastern USA. Forest Ecology and Management. 593: 122906. 15 p. https://doi.org/10.1016/j.foreco.2025.122906.