The global acreage of plantation forests has dramatically increased to nearly 200 × 106 ha by 2000. Most of these trees are planted in areas that once supported very productive natural forests, grasslands, or wetlands. Forest managers around the world are confronting the multifarious tasks of biodiversity conservation, timber production, ecosystem function and stability, and environmental protection of these man-made forests. The history of managing plantation forests is relatively short in Taiwan compared with the case of France, but forest managers in both countries are facing similar bottlenecks in plantation management. In Taiwan, man-made forests covering approximately 420,000 ha in area is an important forest ecosystem. Thinning is a prerequisite activity adopted in the plantation management. But, relevant data regarding the consequences of thinning on biodiversity and on forest function, and endemic vegetation regeneration and restoration are still scanty. Therefore, the purpose of the conference is to investigate the thinning impacts on forest services, forest functions, and biodiversity, and on species variation and population dynamics of vertebrates, invertebrates, fungi, and mosses.