Introduction

Abstract

© 2007, Springer-Verlag Berlin Heidelberg. Approximately 80 % of the land surface area in northern Southeast Asia (Thailand, Laos, Vietnam, Myanmar, Cambodia, South China) is covered by mountainous and hilly highlands, with relatively long valley and inter-mountain depressions. These countries have a monsoon climate with high rainfall during the rainy season which can vary by several hundred millimetres from year to year. These highlands (with altitudes of > 500 m, and slope gradients of <20 to >100 %) are inhabited by more than 2 million hill-tribe people mostly from ethnic minorities. Population growth has put increasing pressure on the natural resources (soil, water, biodiversity). Consequently, environmental and political problems have emerged which are as yet unresolved. With respect to the environment, deforestation and agricultural intensification have led to overuse and deterioration of soil and water resources and a decline in biodiversity. In addition, the application of inappropriate land and water rights, insufficient technical knowledge and inadequate technology transfer have all resulted in inefficient management of natural resources.