The fibrous hemp plant — a botanical cousin of cannabis — has long been used for making paper, textiles, ropes and many other products. In combination with hydraulic lime, chipped hemp stalks are also being made into an intriguing building material known as "hempcrete."  A small building site southwest of Sebastopol is the region's first experiment in using the modern version of this ancient building material.  Reporter Bruce Robinson has the inside story. Architect Steve Sheldon stands in front of his hempcrete building project. Credit: Bruce Robinson