During our drive to Berastagi we saw an unending array of volcanoes.

There around 400 volcanoes, over 130 of them active, in Indonesia, an archipelago vulnerable to seismic upheavals because of its location on the ‘Ring of Fire’, a horseshoe-shaped belt of tectonic plate boundaries that fringes the Pacific basin.

Volcanic eruptions have displaced thousands of people, leaving villages around some mountains deserted, with volcanic ash, lava and mud covering the soil, trees and empty houses. 

In the long term, the ash will create the world’s most productive soils. These soils are most probably the reason that parts of Indonesia can sustain high human population densities, estimated at more than 1,100 people per square km. 

Settlements around the countless dormant volcanoes rely upon the fertile slopes for their crops. They grow vegetables such as potatoes, cabbages, carrots and chilies -- rice and grains -- palms and fruits -- coffee and casava -- breed animals, and operate shops and services. The rich soils can produce multiple harvests year after year without fertilizer and the high volcanic peaks can generate rain.