Gov. Salceda suspended farming, mountain climbing and other activity within a six-kilometer radius around the volcano.

WSJ: Philippines Volcano Spews Ash, Kills 5

Outside these core areas, and at lower altitudes, the culture and farming practices of mountain people can have profound effects on local ecology, making the effects of climate change difficult to distinguish from those directly due to human activities.

UNESCO: 83e

The mountain farms themselves add to this aura, being run using farming techniques little-changed since the Middle Ages.

BBC: Snowbound Slovenia