Fast-growing trees rely on reserves for new spring growth

The carbon and nitrogen needed for plant growth can either come from current photosynthesis and soil N, respectively, or through remobilization of stored resources. Uscola et al. use isotope labeling to study C and N movements in new spring growth in seedlings of four coexisting Mediterranean evergreen trees and find that fast-growing species rely more on stored C and N to support growth of new shoots than slow-growing species. Differences in reserve utilization are thus linked to plant growth capacity, which is a key functional trait of plant fitness, and the different strategies may act to reduce competition for soil N in spring, thereby facilitating coexistence of the species.