Gran Chaco and Chaco Salteño Map of Gran Chaco and Chaco Salteño, Matthias Fries, CDE The Gran Chaco extends from Argentina and Paraguay to the southeast of Bolivia, and is characterized by dry forests. The Gran Chaco is the second-largest contiguous forest area in the Americas after the Amazon. At the same time, dry forests are one of the most-threatened ecosystems on Earth. The Chaco features one of the highest deforestation rates in the world. Alone in the Argentine province of Salta – the Chaco Salteño – over two million hectares of old-growth forests, grasslands, and shrublands were lost in 2015.