The rugged mountains and watersheds of the Esquinas and Piedras Blancas rivers are covered in dense evergreen forest that is home to a number of rare tropical trees and the habitat of many species of birds, mammals and reptiles.

Some of the park has remained in private hands, however a charitable organization Regenwald der Osterreicher (Rainforest of the Austrians) has been raising funds and purchasing these, which up to 2008 had moved 37 km2 (14 sq mi) of land in the area into public ownership.

The Costa Rican government, the hydroelectric company Tenaska (carbon offset joint implementation), The Nature Conservancy and the Gordon and Betty Moore foundation have also purchased land in Piedras Blancas, bringing the total protected area within the park to more than 80%.

Several scientists and students have undertaken studies in Piedras Blancas National Park, using La Gamba Field Station as a base for their investigative trips.

Basilisks and iguanas frequent the streams, anole lizards can be seen in the garden, and geckos can be seen chasing insects in the main lodge building at nighttime.