Forests contain the majority of the biological diversity on the planet. They also play a critical role in storing carbon and in providing other benefits to society. Our knowledge of how forests function depends on our understanding of the drivers of tree growth, death and reproduction. The importance of these drivers may change with tree age, species and environmental conditions. Yet, the nature and relative importance of these different drivers is difficult to study because they act over very long timescales and large spatial scales. This research project will examine tree performance in tropical, sub-tropical and temperate forests to address this challenge. The project makes use of long-term datasets about these forests to understand the slow processes involved. Specifically, the research team will measure growth, mortality and reproductive rates for 16 common tree species, including those that dominate eastern North American forests. The three dimensions of biodiversity- genetic, functional, and phylogenetic- will be integrated in this project. The data produced by the project will be valuable for those studying the biology of forests in this region. Lastly, the project will train one postdoctoral researcher, two graduate students and two undergraduate students based in the United States and will provide two training workshops for early career United States researchers.
Forest dynamics emerge from demographic outcomes on the level of individual trees. This project examines how the fundamental tradeoffs in tree performance are determined by the three dimensions of biodiversity as well as environmental conditions. The core questions of this project are: (1) Are the drivers of the tradeoffs underlying tree performance consistent across a taxonomically and functionally diverse sample of species? (2) How are intra-specific functional and genetic similarity of individuals within a population linked to their demographic success? (3) How does intra-specific functional and genetic diversity vary across populations and how is this linked to tree performance across life stages? and (4) How does variation in the abiotic and biotic environment drive tree performance? The project will use long-term 50 hectare forest plots in the U.S. and China to study tree demography across temperate, subtropical, and tropical forest systems. Reference genome assemblies will be produced for 14 species of phylogenetically diverse trees. Finally, a large greenhouse experiment with tree seedlings under different conditions will help provide mechanistic understanding of the tradeoffs for young trees.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
