Many Brokpa families exchange traditional wooden roofs for more modern corrugated iron ones. They are nowhere near as beautiful but more practical. Also, they have been told by WWF that way they will save a lot of trees.
As there is no road, everything, including building materials, has to be transported to Brokpa villages on foot, along the same path I walked for a week. The usual burden animals - horses and yaks, cannot carry sheets of corrugated iron as they instinctively keep too close to the raised side of the path and brush their load against the rocks.
During that trek I met quite a few people carrying sheets of corrugated iron. They reminded me of Antony Gormley's Angel of the North.
The Himalaya, Eastern Bhutan