Primary tropical forest in Heredia, Costa Rica. Cantarrana Trail. Before everything La Selva Research Station, and all the land between the Sarapiquí and San Carlos River, was occupied by the Botos one of Costa Rica native people. Arqueological studies at La Selva have reported pottery and stone tools found as well as corn pollen from at least 700 yrs ago in this swampy trail. This taught us that primary forests may not be as primary as we thought.