[Water use efficiency and leaf nutrient characteristics of five major tree species in broadleaved Korean pine forest in Changbai Mountains, China].

Water use efficiency (WUE) of five dominant tree species (, , , , and ) was estimated using the stable carbon isotope method in a broadleaved Korean pine forest in Changbai Mountains. Leaf carbon (C), nitrogen (N), and phosphorus (P) contents were measured to analyze nutrient utilization of the dominant species. The relationship between WUE and leaf nutrient contents was systematically assessed. WUE was different due to the variations of micrometeorological factors at different locations in the canopy. The four broadleaved tree species showed upper layer > middle layer > lower layer, while showed upper layer > lower layer > middle layer. WUE of evergreen coniferous was higher than that of two broadleaved species with diffuse-porous wood ( and ) and lower than that of two broadleaved species with ring-porous wood ( and ). The compound-leaved species () had the highest WUE. The WUE of new leaves was significantly higher than old leaves in . The carbon content and C/N of the old and new leaves of evergreen coniferous were significantly higher than those of the other four broadleaved tree species, while nitrogen content and N/P were significantly lower than those of the four broadleaved tree species. P content of old leaves of was significantly lower than that of the four broadleaved tree species. P content of new leaves of current year was not significantly different from that of the broadleaved tree species. The WUE of five tree species had a poor correlation with leaf C content, but a positive correlation with leaf N content. The WUE of evergreen coniferous and deciduous broadleaved tree species was correlated with leaf P content but in opposite direction.