Book excerpt: Provided here are both underlying theory and recent results concerning the propagation and use of clones in research and in production forestry. State-of-the-art science and case histories treating production, testing, multiplication and deployment of clones are presented. Agroforestry, urban forestry and christmas-tree farming are covered, along with more traditional multiple-use forestry and high-intensity forestry for biomass, wood and fiber production. Clonal forestry is contrasted to the more recent developments of "family forestry", and the classical tree-improvement approach relying on seed-orchards. The history of clonal forestry is covered with reviews of several centuries experience with Sugi in Japan and poplars in Europe. The impacts and use of clones in the contexts of genetic conservation and biodiversity are discussed, as are the laws and regulations affecting clonal production and deployment.