EFFECT OF TEAK (TECTONA GRANDIS) PLANTATIONS ON HYDRAULIC CONDUCTIVITY AND POROSITY OF ALFISOLS IN COSTA RICA

Afforestation is thought to improve soil hydraulic properties and recover hydrological services linked to forest systems. However, some researchers do not consider teak plantations as producing environmental services. The influence of teak plantations on hydraulic properties of Alfisols in a moist tropical region (North Pacific coast of Costa Rica) was studied. Saturated hydraulic conductivity (Ksat), porosity and macroporosity were measured at five landuses: secondary forests, grasslands, mature teak (about. 20 years), young cloned teak (2 years) and young coppiced teak (2 years). Three plots were sampled for each landuse and six samples were taken at each plot: three between 0-10 cm deep and three between 50-60 cm. Topsoil (0-10 cm) hydraulic properties varied between the landuses. Ksat: forest > grazed land approximate to coppiced > mature teak approximate to cloned. Porosity: forest > mature teak approximate to coppiced > grazed land approximate to cloned. Macroporosity: forest approximate to coppiced > mature teak approximate to grazed land approximate to cloned. Effects of teak plantations on some soil hydraulic properties depended on the age and management of the plantations. The study found no negative impact of wood extraction on soil hydraulic properties.