The El Yunque Forest is divided into four forest vegetation types that are characterized by different variations in climate, soil, slope and the dominant tree species it is named after.
The Taonuco Forest Type
Characteraized by the tall trees and low light intensities at ground level this forest type is located at elevations below 2,000 ft in elevation, trees grow to a maximum oo about 115 to 125 ft tall. The Canopy trees tent to have very straight trunks with their first branches hig above the ground. Tabonuco and Ausubo tree are the domnant specie but there are plenty of Yageumo, Guaraguo, Laurel Sabino and giant ferns. The Tabonuco Forest cotains the richest flora of the Forest with 175 tree species.
The Palo Colorado Forest Type
It is in essence, an upland swamp of short-statured trees with shallow root systems that begin to occur uphill from the Tabonuco Forest. This forest type has an elevation of above 2,000 ft on gentle slopes and valleys. Here you can find about 50 tree species like Caimitillo Verde and Palo Colorado.
The Sierra Palm Forest Type
Flora in this area doesn't normally attain great hight or large trunk diameters, but it occurs in dense patches within the elevation range of both the Palo Colorado and Tabonuco Forest Types above 2,500 ft. Sierra Palms succed where other trees species cannot, this forest type is found on steep slopes, unstadle soils and streambeds above 1,500 ft.
The Dwarf Forest Type
This forest is also known as "Bosque en las Nubes" or "elfin woodlands" it is found at the upper edges of the Palo Colorado and Sierra Palm Forest Type, near the ridge tops up to 3,500 ft. In this area tree types become shorter, blending into a zone of stanted vegetation. This forest type exist in a zone of water-saturated soils dficient in oxygen. Most minerals imputs for plants become dissolved in the rain and fog. These trees do not grow over 12 ft. Common tree species are Némoco, Roble de Sierra, Limoncillo Guayabota and Camasey.
