Fig. 1

In vitro culture establishment using branches from the provenance trial ‘Berlin climate forest’. a Provenances (black dots) are labeled by number according to Table 2. The distribution area of F. sylvatica is highlighted in blue. b The branches were stored at 4 °C until bud break was initiated under c plant growth chamber conditions in water-filled glass vessels or d greenhouse conditions with constant water flow until e actively growing shoots emerged from both apical and axillary buds. f Shoot tips and nodal segments were taken from actively growing shoots of up to 10 cm in length. After surface sterilization, the nodules were cut longitudinally and placed on medium M1 with the cut side down. The shoot tips were placed upright in the same medium. Four weeks after in vitro establishment, g nodal segments with buds and shoot tips were transferred to M2. The illustration is not to scale. h Shoot formation after 4 weeks of cultivation on M1 and 8 weeks on M2