A Canopy Photosynthesis Model for Dynamics of Size Structure an the Competition Mode in Plant Populations

A dynamic model for growth and mortality of individual plants in a stand is developed,based on the process of canopy photosynthesis, and assuming an allometric relationship between plant height and weight, i.e. an allocation-growth pattern of plant height and stem diameter. The following were shown by simulation: (i) competition between individuals in a crowded stand is never completely one-sided but always asymmetrically two-sided,even though competition is only for light; (ii) plants of the “height-growth” type exhibit a greater asymmetry in competition than plants of the “diameter-growth” type; (iii) the competition mode between plants of the “height-growth” type becomes more asymmetric with increasing photosynthetic ability than with plants of the “diameter-growth” type. These results can explain recent empirical results obtained from several natural plant communities.