Cloning trees through somatic embryogenesis (SE)is considered by the industry to be an important new technology. When integrated with conventional breeding, and by facilitating and being enhanced by DNA technologies, SE will allow much faster genetic improvement of forest trees. Thus it will be a key to meeting the increasing demand for wood products per hectare of commmercial forest land. In its present form, SE technology typically consists of six to eight separate steps, starting with the initiation of embryo suspensor masses (ESM) from seed and ending with delivery of tree clones to the field. The main challenges are (1) increase the number of genotypes getting past the first step, (2) increase through-system yields, and (3) decrease the costs associated with converting cloned embryos to plants. The first limits our ability to discover outstanding clones through clonal field tests now being established. Challenges 2 and 3 must be met to allow scaled-up propagation of selected clones (from cryogenically stored ESM) by the time these tests have run their course (5+ years). To help the current effort, biochemical engineering research and development is needed in areas such as (1) measurement of in-ovulo environments, and their simulation in vitro (including novel bioreactor development), (2) quantification of culture response, through understanding cell lineage and culture chemistry, improved image analysis, molecular markers, etc., (3) machine separation and selection of embryos in liquid culture or on plates, and (4) development of embryo-to-soil delivery systems, such as manufactured seed. Commercialization of the cloning process through these efforts will usher in an era of more productive forests and a broadened range of competitively priced forest products worldwide.