Shoot multiplication from mature trees of Douglas-fir (Pseudotsuga menziesii) and sugar pine (Pinus lambertiana)

Opening of apical and axillary buds of mature Douglas-fir and sugar pine trees was obtained on a newly formulated basal medium (DCR) without growth regulators. Elongation of buds was observed on 1/2 strength DCR with 0.3% activated charcoal (DCR-1). In sugar pine, multiple shoots were obtained when explants on DCR with 0.5 mg/1 BAP for 5-6 weeks were transferred to DCR-1 medium. On subculture, axillary buds again developed when shoots were cultured on DCR with 0.2 mg/1 BAP for Douglas-fir and 0.5 mg/1 BAP for sugar pine. These buds were again elongated on DCR-1 medium. By subculturing 7-10 shoots of Douglas-fir and 2-3 shoots of sugar pine, over 100 shoots can be obtained in a year.