Effects of Elevated CO2 and Nitrogen Loading on the Defensive Traits of Three Successional Deciduous Broad-Leaved Tree Seedlings

To elucidate changes in the defensive traits of tree seedlings under global environmental changes, we evaluated foliar successional trees, such as beech, oak, and magnolia grown a natural-light phytotron. Potted were combination two CO2 concentrations (360 vs. 720 ppm) nitrogen (N) treatments (4 15 kg N ha?1 yr?1) for growing seasons using quantitative chemical analyses anatomical method. We hypothesized that effects depend on type, with late species providing greater defense their leaves against herbivores, this exhibits determinate growth. Beech, species, responded most to both elevated concentration (eCO2) high treatment. eCO2 low supply enhanced traits, leaf mass per area (LMA), carbon ratio (C/N ratio), increase total phenolic condensed tannin agreement carbon–nutrient balance (CNB) hypothesis. High decreased C/N due uptake beech leaves. Oak, mid–late exhibited different responses from beech: LMA, ratio, phenolics oak leaves, but only increased supply. Magnolia did not respond all treatments. No interactive observed between except oak. Although amounts compounds varied treatments, distribution these change. Our results indicate forest loading are related type.