The park covers an area of 100 km², but the forests cover only 4% of its surface. The national park is known for having the northernmost Valdivian temperate rain forests. The coastal fog (Spanish: Camanchaca) hangs on the mountain-slopes and moistens subtropical vegetation, allowing the hydrophilic forests to survive despite of being surrounded of semiarid scrublands, with rainfall no more than 113 mm annually. Actually, 113mm is the average rainfall. The forest is a vestigial survival of the last glacial period.
Typical plants of the national park include:
The park also includes a large number of smaller animals, as Degu, Chinchilla and foxes. Many different kinds of birds live in the park, such as the Chilean Tinamou (Nothoprocta perdicaria) and the Long-tailed Meadowlark (Sturnella loyca).