Establishment of two indigenous timber species in dairy pastures in Costa Rica

A silvopastoral model that combines the production of pasture herbage with valuable native timber species has potential to simultaneously address the multiple goals of reforestation, conservation of native species and enterprise intensification. The objective of this study was to design, establish and monitor early growth of a silvopastoral experiment on a dairy farm in the north Atlantic zone of Costa Rica. Two indigenous timber species, Vochysia guatemalensis and Hyeronima alchorneoides were planted with and without the tropical pasture legume, Arachis pintoi in a split plot design, (2 × 2) factorial arrangement of treatments with four replications. After the first two years, V. guatemalensis was significantly taller (3.1 m) than H. alchorneoides (2.5 m). The mean root collar diameter for V. guatemalensis was significantly larger (6.5 cm) than H. alchorneoides (4.5 cm). Two-year establishment was acceptable for the tree component (83 to 85% survival) but poor for A. pintoi (2 to 8% of the sward). The most important pest affecting the establishment of the timber species was the leaf cutter ant, Atta cephalotes. An insect larvae, Cosmopterix sp., severely damaged 39% of the V. guatemalensis trees by repeatedly attacking their apical meristems. The two-year establishment data was insufficient to accurately predict future wood volume. A hypothetical economic analysis concluded that the silvopastoral system must average at least 1.2 m3 wood volume/paddock/year (20 m3/ha/year) throughout the first ten years of growth to assure a positive economic return from timber. The experiment is planned for a ten year period, which corresponds to the estimated rotation length for harvesting the timber species.