The mountainous uplands of mainland Southeast Asia have for some timeconstituted one of the largest – and environmentally most fragile – frontiersof development in Asia. The isolation and economic backwardness of thisregion is highlighted by its close geographic proximity to some of the mainpopulation and economic centres in Asia. Inhospitable terrain and a lack ofroads and other physical infrastructure have hindered the integration withtheir economic and demographic heartland in the coastal areas. Politicalobstacles to integration have arguably been even more important. Theregion is criss-crossed by national borders and falls under the jurisdictionof six countries