Spatially explicit individual-based simulator for forest plantations

We present a planted forest growth simulator prototype based on the individual-free model approach. The model represents the stem diameter and crown growth for trees in a teak plantation (Tectonagrandis L.f) with no silvicultural interventions. Tree growth is regulated by the degree of competition among frees defined as an empirical relationship reflecting the constraints in resource availability (light, water, nutrients) for an assemblage of frees with respect to their requirements for optimum growth. The model was implemented in the SIMILE visual-declarative language. The model uses a data file with initial information on free size (diameter at breast height) and their spatial coordinates. The competition intensity to which each tree is subjected depends on its relative size and distance in relation to competitor trees. Competitor trees are those whose crown radii intercepts with the crown radius of the "subject" tree. A mortality function depending on free size determines the probability of frees dying. Model runs evidenced a reasonable behavior in the growth of individual frees and the stand when compared with growth observed under actual conditions.