Oak trees are considered a keystone species in forests throughout the eastern United States, as they provide essential pulses of food resources to wildlife populations through masting events. Masting events are the synchronous and highly variable production of fruit within a population. Although several hypotheses have been proposed to explain why masting evolved in plants as a reproductive strategy, the factors that trigger any particular mast event are still not well understood. This is partly due to the lack of sufficient long-term data (i.e., even a 10-year study may only have 2 or 3 mast events). As this is a population-level event, weather-related variables are thought to play an important role for triggering a mast event.
Thus, the goal of this study was to analyze the link between weather variables and masting events in black oak (Quercus velutina Lam.) and chestnut oak (Quercus montana Willd.) in southeast Ohio. Cues for masting are expected to differ between the species, as black oaks take two years to mature their acorns, while chestnut oak mature their acorns within a single season. We used data from a long-term study, which followed acorn production of seventy-two black oak and seventy-two chestnut oak trees for sixteen years.
Results/Conclusions
Preliminary analyses found that spring temperature and spring precipitation of the current year had strong positive associations for predicting the probability of a mast event, for both chestnut oak and black oak. Increasing spring temperatures and spring precipitation increased the likelihood of masting for both species. Humidity and wind speed variables had no significant impact on the probability of masting events for either black oak or chestnut oak. These results support previous studies, in that spring weather conditions are critical to the maturation of acorns. Identifying the connection between weather and mast events is vital for predicting future mast events, and for understanding how food resources for wildlife populations may be impacted under climate change.