In recent years, illegal logging and human encroachment have put great strain on this ecoregion.

[2][3][1][4] The ecoregion runs for 1,600 km down the northeast and southwest sides of the Barisan Mountains on the island of Sumatra.

The characteristics trees in the lowland rain forest are those of family Dipterocarpaceae (Greek: di = two, pteron = wing and karpos = fruit).

Mammals and birds are very diverse, with species similar to Borneo and the Malaysian Peninsula as all three landmasses were connected in the last ice age.

Many endemic species are found in the biodiversity hotspot around Lake Toba, located in the caldera of a supervolcano.