New Delhi, March 1 -- The wooden bath dominates the well-appointed room that looks over tall blue pine trees and colourful prayer flags fluttering in the wind. Glowing river stones, slow-heated over a fire, drop down a slanted chute, warming the water and gently disseminating minerals. Leaves crowd the surface of the steaming water, inviting me to slip into the tub and relax. The stage is set for a Himalayan Hot Stone Bath, a signature therapeutic treatment that's been part of Bhutanese life for centuries.

But why a bath tub made of wood? I turn to the spa attendant at Amankora Paro, a luxury resort shrouded by a pine forest so verdant that it scents the crisp Himalayan air. Won't it be prone to mildew, cracks and leaks, I ask.

"A hard ...