Abstract
We examined the indirect positive effect of one plant on the growth of another via growth suppression of a shared competing plant as an indirect facilitation between plants. We simulated the dynamics of populations of 3600 competing plants and used absolute interaction intensity (AIIi,j), the causal effect of plant j on plant i. The positive effect due to indirect facilitation between two plants occurs at a short distance apart and increases with increasing average density. The indirect facilitation between plants becomes increasingly important with increasing average density to explain the dynamics of size structure in plant populations.
