Considerable progress has been made during the last three years in developing databases and analytical methods to answer the questions: What tree will grow where and how well will it grow? These proceedings present the results from a workshop held in Bangkok in April 1995. Topics covered included the development of climatic interpolation relationships, climatic mapping programs, Plantgro applications and simulation mapping programs. The work reported is based mainly on studies in China and Southeast Asia, but also includes examples of programs developed for Australia, Africa and Latin America. While the emphasis of these proceedings is on forestry, the climate and soils data collated and developed will be valuable for many other areas of research.