Photosynthetic induction times and photoinhibition in relation to simulated sunflecks (sudden increase of irradiance from 20 to 1,500 lmol m -2 s -1 ) were examined in leaves of co-occurring Fagus lucida (a deciduous tree) and Castanopsis lamontii (an evergreen tree) saplings grown either in a beech forest understory or in an adjacent open site during a late rainy season. Two hypotheses were tested: (1) understory leaves would display faster photosynthetic induction times and greater photoinhibition than open-grown leaves; and (2) evergreen species would have slower photosynthetic induction times and lighter photoinhibition than deciduous species. Times to reach 90% of maximal CO 2 assimilation rate (t 90%A ) and stomatal conductance ðt 90%g s Þ did not differ between species, but showed faster by 3-5 min in open-grown leaves than understory leaves due to higher initial stomatal conductance (g s initial ) and induction state 1 min into simulated sunflecks (IS 1min ) in the former. Our analysis across the published data on photosynthetic induction of 48 broadleaved woody species again revealed the negative correlations between t 90%A and either g s initial or IS 1min , and the similarity of t 90%A and t 90%g s between evergreen and deciduous species. Measurements of maximum PSII photochemical efficiency (F v /F m ) indicated that photoinhibition occurred in saplings in any of the growth habitats during sunfleck-induced photosynthetic induction. Despite no interspecific differences in the degree of photoinhibition, understory leaves of both species suffered heavier photoinhibition than open-grown leaves, as indicated by a stronger decrease of F v /F m in the former. Dynamic changes in the quantum yields of PSII photochemistry and DpHand xanthophyll-regulated thermal dissipation and adjustments in the partitioning of electron flow between assimilative and non-assimilative processes were functional to resist photoinhibition. However, such photoinhibition, together with stomatal and biochemical limitations, would decrease carbon gain during simulated sunflecks, particularly in understory leaves.

We used leaf economics spectrum (LES) theory to explain the bimodal elevational distribution of evergreen tree species, which is one of the most puzzling biogeographic patterns in the world. Our results suggest that elevation acts as an environmental filter to both select the locally adapted evergreen and deciduous species with sufficient phylogenetic variation and distinct leaf economic strategies and regulate their distribution along the elevational gradient based on their coordinated spreading of phylogenetic divergence and leaf economic variation. If species are filtered from regional species pools, changing climate may affect both the species and leaf economic composition of plant communities.