The Joint Research Project on Rehabilitation of Tropical Rainforest Ecosystem was initiated in July 1991 by Universiti Putra Malaysia (UPM) and Yokohama National University, Japan (YNU) with sponsorship from Mitsubishi Corporation. The project is based on the success of restoration of native forest land in Japan and results of some field surveys conducted in the forests of South East Asian countries since 1978. The scientific basis of the project is based on the concept of vegetation association by Prof. Akira Miyawaki from Yokohama National University.