A general model for mass-growth-density relations across tree-dominated communities

A general allometric scaling model predicts that plant body mass M _T will scale as the -4/3 power of plant density N. Here, we show how this model predicts numerous other scaling attributes of plant populations and communities, including annual growth rate G_T, standing leaf biomass M_L, basal stem diameter D, and above- and below-ground biomass, M_SH and M_R. These predictions are consistent with the 'Law of Constant Yield' (i.e. productivity is independent of plant density). Analysis of worldwide databases for woody plant-dominated communities spanning seven orders of magnitude in M_T and five orders of magnitude in N provides strong support of all of the model's predictions. Our model thus offers a theoretical basis for understanding and predicting the effects of crowding on plant size, growth and biomass partitioning across diverse ecological communities.