VEGETATIVE PROPAGATION OF POPULUS SPP.: I. INFLUENCE OF TEMPERATURE ON FORMATION AND INITIAL GROWTH OF ASPEN SUCKERS

Abstract

Populus tremuloides Michx. (trembling aspen), a commercially valuable tree, generally reproduces vegetatively by shoots (suckers) that arise adventitiously on lateral roots. Among various ecological factors, temperature plays a significant role in sucker initiation. The influence of five temperature regimes on suckering is reported here. Root cuttings of aspen, 10 cm long and 1.2 to 2.5 cm thick, were grown in the dark in fine sand. The temperature of the sand was kept at 58°, 64°, 74°, 87°, and 95 °F, and the moisture content near field capacity. The earliest emergence of suckers was at 87°. The maximum incidence and growth of suckers was at 74°, declining gradually below and above this temperature. Sufficient food material is stored in short root sections to sustain suckers for more than 3 weeks. These data agree with our field observations and indicate that after such disturbances as cutting and burning, insolation-induced increase in soil temperature is the cardinal factor for sucker stimulation.