The Use of Canopy Models to Analyze Light Competition Among Plants

Abstract

Competition for light among plants is an important factor determining plant trait evolution and community dynamics. It may also strongly modulate crop production. Canopy models provide a useful means of analyzing light competition. This use however entails that these models take account of the interactions between individual plants in vegetation stands, which is challenging. Here we first discuss how light acquisition and photosynthesis by individual plants in vegetation stands can be modeled focusing on relatively simple approaches to this problem. We then give examples of how such canopy models have been used to analyze plant light competition in natural vegetation and in crops. We first analyze the extent to which competition for light is size asymmetric. We demonstrate that, contrary to common belief, this is not always the case. Notably competition between plants of different species tends to be more symmetric than competition among plants of the same species. We then focus on crop-weed interactions, and show how canopy models have enabled us to identify the traits that make crops most effective in competing with weeds. Together these examples illustrate how canopy models can strongly contribute to our mechanistic understanding of plant competition for light.