Dataset for Heterogeneous Tree Responses to Temperature, Precipitation, and Snowpack across Sites and Recruitment classes, 2008 to 2024

Forest species require sufficient recruitment of new individuals to maintain their populations. However, the environmental conditions that support recruitment, e.g., optimal temperatures and water availability, are shifting. Across a species distributional range environmental changes will differ as will the effects of similar environmental shifts, making predictions of future recruitment a challenge. Multi-site studies can reveal how drivers and responses to environmental change vary, information that can be considered when predicting future dynamics elsewhere. In this study, we analyze 17 years of seedling recruitment data for two widespread Eastern North American tree species, Acer rubrum and A. saccharum. Data were collected across several populations at two latitudes. Our goal was to identify the environmental conditions, temperature, precipitation and snowpack, influencing recruitment and the variability of responses. Our results show strong heterogeneity in environmental effects across species, locations, and—most notably—ontogenetic stages (newly established vs. older seedlings >1 year). Newly established seedlings had a 9.5% survival rate, compared to 98.9% for older seedlings. Survival rates did not differ between species or latitudes, but the environmental factors most strongly associated with survival did. Each combination of species, ontogenetic stage, and latitude had a unique set of predictors. While our findings support previous work on the importance of environmental conditions for recruitment, they highlight the establishing year as a strong bottleneck in the recruitment process, with later stages being much less affected by environmental fluctuations, they also highlight the complexity and variability of these processes, providing a more nuanced understanding of tree recruitment dynamics under changing environments.