Of course in a refugee camp you have a desperate need. They're not doing this for environmental reasons. They're doing this to survive. I hope not. I'd like to think that people will start using sensible methods before we've deforested the whole world.
Solar cooking can slow down the deforestation.
The cardboard manufacturer takes a large roll of corrugated cardboard and laminates aluminum foil on one side and sprays a waterproofing wax on the other side. This is then die-cut to form the cooker, complete with the folds and slots. It can all be done rather quickly once he works us into his production schedule. If we could have orders larger than the 1000 or 1500 we have been ordering, the price would drop somewhat. He knows what we are using the cardboard for and has graciously absorbed the recent paper price rises.