Variations in leaf economics spectrum traits for an evergreen coniferous species: Tree size dominates over environment factors

Many leaf traits strongly vary with tree size and environmental factors, but the importance of these factors to intraspecific variations of leaf traits in forest trees have rarely been simultaneously evaluated.
We measured needle longevity and specific leaf area (SLA) and nitrogen (N) content of every needle age (0 to 4 year old) for 65 individuals with 0.3-100 cm diameter at breast height (DBH) for an evergreen coniferous species, Pinus koraiensis Sieb. et Zucc., in Northeast China. We simultaneously evaluated effects of tree size (DBH or tree height) and environment factors (light intensity, soil N content and water availability) on the needle longevity, SLA, foliage N content as well as the slopes of regressions of SLA and foliage N content against needle age.
All of the studied leaf traits and slopes of regressions of SLA and foliage N content against needle age were significantly related to tree size. Tree height had a greater impact on SLA and area-based leaf N content (Nar...