The treeline elfin forest is the upper limit of montane forest. Its topographic complexity is reflected in its vegetation, presenting two or three layers of trees throughout the steep slopes. This forest has small trees that are characterized by the twisted growth patterns of their trunks and branches and their small, fleshy and hard leaves.

There is an abundance of non-vascular epiphytes species (mosses, lichens) that cover the branches and trunks of these trees. This zone also hosts stands of threatened keñua trees (Polylepis sericea).

Its main function is water catchment and maintenance of the flow rate of different waterways.