Limited material availability during times of disaster relief reconstruction is a major concern and involves increased market prices. Paper tubing on the other hand, not being a typical building material, is comparatively inexpensive and very accessible. In a special case in Turkey in 1999, Ban was able to get paper tubing for free. Paper tubing also proved advantageous for building emergency shelters during the Rwanda refugee crisis in 1994, where the use of trees for framing was creating deforestation problems, and alternative construction materials were difficult to find. The United Nations supplemented wood with aluminum piping but this was very expensive, and in the end the refugees sold off the aluminum for money. The refugees then reverted to cutting trees for building materials."pg30" Switching to paper tubing for frames helped save money, prevent theft and conserve the local trees. Ban's paper tube shelter design from Rwanda's Byumba Refugee Camp was featured in a PBS News Hour story.