They might be raising the distinction between "rain forest" and "jungle".

As I understand it, A rain forest is a tropical forest characterized by a dense canopy that blocks most sunlight from reaching the floor; it has relatively little undergrowth.

A jungle is a tropical forest without a dense canopy, and so has heavy undergrowth. This frequently exists on the edges of a rain forest or in other areas where storms, etc prevent the growth of a dense canopy.

Maybe "jungle" does not apply to much of this land in Colombia?