Short-term flooding effects on root suckering of quaking aspen

Unexpectedly few root suckers may develop following summer clearcuts of quaking aspen (Populus tremuloicles Miclix.) on sites withflne-textured soils and level terrain. We hypothesized that the poor regeneration is partially a result of the flooded soil conditions that follow such harvests, and that the damage would increase with duration of flooding and temperature. Root segments from ca. 45-yr-old aspen trees were planted in saturated mixtures ofO and A horizon soil material for 2, 6,10, and 14 days at relatively warm and cool temperatures (12 hr day/night temperature regimes of28/20°C and 20/12°C, respectively). The root segments were then transplanted into moist soil at ambient O₂ for an additional 14 to 38 days. Suckering was significantly reduced by increased flooding duration and by flooding at wanner temperatures. The percentage of segments that suckered decreased exponentially with accumulated growing degree days during flooding. Saturated soil conditions can inhibit aspen suckering in controlled environments and may have the potential for precluding successful regeneration following clearcutting.