Light Interception, Nitrogen and Leaf Mass Distribution in a Multilayer Plant Community

The distribution of light interception, foliar nitrogen and leaf mass between three community layers (tree, herbaceous and moss layers) were investigated along productivity gradient in a west-Estonian wooded meadow. A two-resource model is applicable to describe the vertical structure of a multilayer community. Upper layers have better access to light compared to lower layers of the canopy, whereas lower layers have higher nitrogen-use efficiency and/or better ability to acquire nitrogen. The amount of foliar nitrogen per unit of intercepted light is highest in the herbaceous layer if compared to the tree and moss layers but mosses have the highest nitrogen-use-efficiency (assessed from the dry mass :nitrogen ratio). The growth of the herbaceous layer in communities along the productivity gradient is co-limited by light and nitrogen but growth of the moss layer is limited only by light availability.