IDENTIFYING FAST-GROWING NATIVE TREES FROM THE NEOTROPICS USING DATA FROM A LARGE, PERMANENT CENSUS PLOT

To screen for rapidly growing trees, lifetime growth histories of 160 species were estimated from data collected in a permanent 50 ha census plot in tropical moist forest in Panama, Most of the 160 species had never been studied before in detail, and newly encountered species with rapid growth might provide better techniques for reforesting degraded soils in Central America. To estimate life-time growth, polynomial regressions were fitted to instantaneous growth rates expressed as a function of log-transformed diameter at breast height (dbh). These functions represent a differential equation in dbh, and explicit solutions for the equations provided dbh trajectories as a function of age (starting at 1 cm dbh, which was the smallest size included in the census). Dbh trajectories were calculated for 160 species, and full growth data are presented for the 28 species that ranked among the fastest 15 to reach a dbh of 10, 30, or 60 cm. Dbh trajectories based on growth of one standard deviation above the mean were also estimated for these species by fitting a polynomial regression to the residuals around the original regression. The fastest-growing tree in the 50 ha plot was the balsa, Ochroma pyramidale, which reached 10 cm in 5 years and 30 cm in 10. Cavanillesia platanifolia, Trema micrantha, Zanthoxylum belizense, and Vochysia ferruginea were the other top-ranking species. At mean growth, the top 15 ranking species required 5-25 years to reach 10 cm, 10-67 years to reach 30 cm, and 32-111 years to reach 60 cm, starting at 1 cm. At growth one standard deviation above the mean, the same species required 4-18 years to reach 10 cm, 8-35 years to reach 30 cm, and 19-69 years to reach 60 cm dbh. We recommend that the little-known species from this list be further tested in reforestation trials.