Growth equations and rotation ages of ten native tree species in mixed and pure plantations in the humid neotropics.
Ten percent of the world's forest consists of plantations, yet these plantations supply 37% of the world's timber. While plantations proliferate, local communities are looking for suitable native species to cultivate in plantations. This paper is a component of a larger project - trying to restore degraded areas with native plantations in ways that would financially benefit the surrounding communities. Growth equations have been constructed for ten native tree species, using 12 years of growth data from research plots in La Selva Biological Station, Costa Rica. Interpolative growth equations for Terminalia amazonia (J. Gmell) Exell., Virola koschnyi Warb., Dipteryx panamensis (Pittier) Record & Mell, and Hieronyma alchorneoides Allemao were constructed. A maximum sustained yield approach was used to determine the other six species' rotation age and the merchantable volume produced per hectare at time of harvest. In single-species plantations, Jacaranda copaia (Aubl.) D. Don., Vochysia guatemalensis Donn. Sm., and Vochysia ferruginea Mart. were the most productive species and, thus, are the recommended plantation species for the humid lowlands of Costa Rica. The data for this experiment suggest J. copaia has an ideal rotation age of 6.5 years, at which time the yield will be 255 m3/ha. V. guatemalensis has a rotation age of 13.5 years producing 417 m3/ha, and V. ferruginea has a rotation age of 13.3 years producing 363 m3/ha. J. copaia and V. guatemalensis grew significantly faster in mixed plantations than in pure plantations. A mixed-species plantation comprised of J. copaia, V. guatemalensis, and Calophyllum brasiliense Cambess produces 21% more total volume of merchantable timber than a pure plantation of J. copaia, which grows the fastest of the three species. Restoring abandoned agricultural sites with V. guatemalensis will yield the most timber to landowners after one rotation.