Several biological properties of Albizia procera, a woody weed of pastures in Puerto Rico are described in this study. This species is reproductively mature after approximately three years. Medium sized trees growing in the open can produce 3,500 pods in one year. Most of the pods and seeds fall within the extent of the crowns. The first 6 cm of soil under a 15-year-old A. procera stand had a seed bank of 315 seed per m2. Seeds experimentally buried at 2.5 cm under the surface decay at an exponential rate of 0.33 seeds per year with a half-life of 2.1 yr. This study discusses implications of these biological properties for pasture management.