Variation and relationships between twig and leaf traits of species across successional status in temperate forests

Abstract

ABSTRACTRelationships among twig size, leaf size and leafing intensity are essential for predicting structure and function of twigs and leaves and ability of plants to acquire different environmental resources. We aimed to test whether trade-offs between twig and leaf traits for species would be influenced by forest successional status and sampling orientation within canopy. We measured four twig and leaf traits for seven coexisting broadleaf species across successional statuses in mixed broadleaved-Korean pine (Pinus koraiensis) forests in Northeast China. The results showed that both twig and leaf traits varied with successional status and twig level explained the largest variations in traits. Slopes of regression of leaf traits (i.e. individual leaf area, total leaf area and volume-based leafing intensity) against twig cross-sectional area were late-successional species > middle-successional species > early-successional species. Relationships between twig cross-sectional area and total leaf area in upper south and lower north canopy orientations did not vary with successional status of species. However, slopes of regression of twig cross-sectional area against total leaf area varied with successional status in other four sampling orientations. Our results highlight the importance of successional status and sampling orientation within canopy in controlling variations and trade-offs between twig and leaf traits.