The adventitious bud forming ability of Sitka spruce (Picea sitchensis (Bong.) Carr.) buds in vitro was found to be dependent upon the age of tree from which the explants were taken. Bud formation declined exponentially with increasing tree age when 1.0 and 10 μM 6-benzylaminopurine (BA) were used to induce adventitious buds. When less BA was used (0.1 μM) bud production was much lower with all ages of tree and no mathematical relationship between declining bud production and tree age was found. By a tree age of 6 years bud-forming ability had declined severely. Even the few buds that developed on older tree tissues failed to elongate into shoots, became necrotic and eventually died, indicating that adventitious bud induction in this species is not a rejuvenative process. Callusing of bud explants also declined with increasing tree age when 0.1 μM BA was used whilst very little callusing occurred at the higher cytokinin concentrations (1.0 and 10 μM BA). Tissue necrosis in vitro increased with tree age, whilst the ability of BA to retard necrosis declined with increasing tree age. Buds from epicormic shoots, formed on the lower trunks of 20-year-old trees when these were exposed to light, were not significantly better at forming adventitious buds in vitro than buds taken from the lower branches of the crown.