From the Earthville Blog:
The biggest news on the construction of the Dharmalaya Institute is in regard to our race against time to get the roof on our baby building before the onslaught of the monsoon rains this month… and the update is that, well, we couldn’t win, so we’ve done our best to change the game.
To understand the snag, one must first have an idea of the way traditional roofs are built here in Bir and around the Kangra Valley. Local roofs are gable roofs made of slate shingles fastened to a truss of wooden struts supported by bamboo rafters. The strength of the roof relies primarily upon the bamboo, and the strength of the bamboo, in turn, depends upon not only size and age of the bamboo but also the time of year when it is harvested.
For maximum durability, the bamboo must be cut during the new moon of late December or early January. If that sounds like hocus pocus, then consider that this is the time of year when the plant is most dormant and thus its sugar content is lowest. If bamboo is cut at other times of year, the more plentiful sugars harden as starches, a delicacy for termites and other critters. When feasted upon, such bamboo loses much of its strength and no longer can be counted upon to do its job holding the building up (and so must be replaced, generally within 10-15 years). When bamboo is cut at its most dormant moment, however, it contains very little that is appetizing to insects and thus the structural integrity and strength of the bamboo remains intact for decades (and, in some cases, such as when it is thoroughly smoked, it can last for centuries).