Vegetative succession describes the turnover of plant species through time. This turnover enables coexistence of species temporally, but also spatially as different locations co-occur at different successional stages. Moreover, the suite of species that occupy different successional stages varies due to heterogeneous environments across both local and regional spatial scales. Understanding the processes that underlie succession as well as those that drive spatial variation in the species that comprise similar successional stages is a central goal in ecology. In order to understand these processes in this dissertation, I recast species into functional traits that connect species physiologies to their environments. Using a suite of traits thought to influence species success at various stages of succession, I examine functional trait changes through time in plant communities of the eastern US. Chapters 2 and 3 use an old field experiment to examine how soil nutrients and plant enemies influence temporal dynamics of early secondary succession by examining species-level trait responses (Chapter 2) and community-level trait responses (Chapter 3). Old fields are important and well-studied community types due to their frequency in the landscape and lend themselves well to experimental manipulation given the relatively rapid life cycles and small stature of their constituent herbaceous species. Chapters 4 and 5 use a continental-scale forest database to examine similar processes in trees, albeit at larger spatial and temporal gradients. Chapter 4 uses a space-for-time substitute approach to ask how tree community traits change along a forest age gradient, while Chapter 5 asks how traits of tree seedling communities respond to forest disturbances using resampled plots. In Chapter 6, I synthesize my findings on trait responses to successional gradients in these two distinct successional stages. Overall, I found that seed mass, indicative of dispersal strategy, and investment in structural biomass (plant height and wood density) capture plant successional strategies. Leaf traits, however, did not consistently vary with succession or the manipulated environmental gradients in the old field experiment. Rather, leaf traits displayed large, unexplained variation across space, suggesting that they are responding to processes related to spatial heterogeneity independent of succession. Advisors/Committee Members: Wilfahrt, Peter, White, Peter, Peet, Robert K., Mitchell, Charles, Bruno, John, Wright, Justin.