Trees were produced from firm white callus tissue of triploid quaking aspen (Populus tremuloides Michx.), initiated on a modified Wolter and Skoog defined medium and subcultured monthly for two years. When subcultured to medium without auxin, kinetin or supplements, but containing 0.15 mg/liter BAP (6‐benzylaminopurine), multiple stunted shoots appeared on most inocula. However, at 0.05 mg/liter BAP, only a few vigorous shoots per piece were initiated, but seven rooted on the callus: two in the dark with BAP and five in 200 ft‐c of light with 0.04 mg/liter 2,4‐D. After proliferation of the roots on the medium surface, four shoots elongated and were planted in semi‐sterilized soil, then were given 3100 ft‐c of light for rapid growth into trees. Both light sources were on for 16 hr/day. Two trees were also grown from stunted shoots excised from the callus and rooted in soil.