Growth of native forest species in the north area de Costa Rica

Abstract

The performance of 5 of the most frequently planted species in reforestation in the humid lowlands of Costa Rica was evaluated. The study was developed based on a series of permanent plots from the Native Tree Species for the North Zone Project, of the Technological Institute of Costa Rica. The permanent plots (8 to 11 years old) were established in the 90’s in the 4 major climatic/soil strata in which the north zone of Costa Rica was subdivided. The behavior and growth (based on the dbh and total height) of plantations with the native tree species almendro (Dipteryx panamensis), pilón (Hyeronima alchorneoides), fruta dorada (Virola koschnyi), botarrama (Vochysia ferruginea), and cebo (Vochysia guatemalensis) were studied. Growth and increment analysis on the variables measured was made. Cebo plantations overgrew all other tree species, reaching a maximum dbh of 24.6 cm (11 years old) and a basal area of 29.2 m² ha^-1 (9 years old). Pilón and botarrama registered the best growth after cebo. Almendro was the tree species with the lowest growth in all variables, with 10.3 m² ha^-1 in basal area and a maximum dbh of 12.6 cm (11 years old). The highest growth values were registered in Ultisols. There were significant differences in current annual increment and mean annual increment of the basal area among the 4 climatic/soil strata. A negative relationship between basal area and humidity was found. However, the cebo did not show any relationship as for the climatic/soil strata, and exhibited good growth in all sites, and fruta dorada showed best growth in Inceptisols. The ratio dap/heigth showed almendro and pilón with a faster height growth than its diameter, which later could originate wood growth tensions. These tree species, selected for reforestation in the north zone of Costa Rica, all showed promising features and adaptability to site conditions like: clay soils, acid soils (pH from 4,5 to 6,0), low fertility and drainage problems.