9801455 Bazzaz This research will investigate the function of leaf lifespan in relation to other plant traits and to habitat in 15 co-occurring species of the oak genus. Leaf lifespans will be used to characterize oaks into functional groups that may be used to predict responses to elevated CO2. The research will be conducted on mature trees in three field sites in northern Florida and on seedlings in greenhouse experiments. The study system provides a large number of closely related species which are structurally and physiologically very similar, and are all found in the same geographic region, but which have contrasting leaf lifespans. This permits study of traits that vary with leaf lifespan, without additional trait variation due to different evolutionary origins or to climatic differences. The research has three major components: 1) quantification of the relationships between leaf lifespan and plant traits important for carbon, nutrient and water utilization in oaks, 2) a field survey of abundance and percent cover of oak species across soil moisture and nutrient gradients to determine whether leaf lifespan is correlated to soil properties, and 3) a greenhouse experiment to determine whether leaf lifespan is a useful parameter in predicting growth enhancement of oaks under elevated CO2.
