Climate change is projected to have strong effects on plant performance in the future due to warmer temperatures, novel biotic interactions, and changes in resource availability. These dynamics are well-established, but there is a continued need for scientists to investigate how different aspects of climate change will interact in determining net effects on plant performance. Furthermore, ecologists are increasingly tasked with understanding the mechanistic physiological underpinnings of previously observed patterns and trends in performance in order to increase the accuracy of our predictions. In this study, we investigated whether climate change will alter the availability of spring light availability for temperate tree seedlings as a function of their and the canopy’s foliar phenology. We then used photosynthetic parameters obtained from models using in situ gas exchange measurements on the same seedlings to predict if changes in light availability will result in significant changes to net annual carbon assimilation.
Results/Conclusions
Our results suggest that seedling leaf expansion is more sensitive to climate than canopy leaf expansion and that seedlings will therefore gain access to light availability in spring that would otherwise be limiting. However, our models also predict that the resulting increase in spring carbon assimilation will be largely offset by higher respiration costs and lower assimilation rates in summer resulting from higher temperatures and reduced water availability. Finally, we found evidence for biotic interactions mitigating the overall effects of climate change, with seedlings having improved performance when planted under Acer saccharum adult trees than when planted under Quercus rubra adult trees.