EFFECT OF LOCAL COMPETITION ON RESPROUTING OF ARBUTUS-UNEDO AFTER CLIPPING

To evaluate the effects of local competition on the growth and size va riability of sprouts following disturbance in a natural population of Arbutus unedo in Catalonia, plants were cut at the base and a neighbor removal experiment was performed. Removal of neighbors resulted in an increase in the number and biomass of sprouts at 2 and 7.5 months aft er clipping. Number and biomass of sprouts was also correlated with in itial plant size (stump area). Inter-genet competition appeared to be symmetric, and acted to delay the onset of interference among sprouts within a genet. Size variability of sprouts on an individual was posit ively correlated with their density on the stump, supporting the hypot hesis that competition among ramets (sprouts) within a genet is asymme tric. Reduced inter-genet competition from neighbor removal resulted i n an increase in the number and biomass of sprouts growing from a stum p. This resulted in an increase in the asymmetry of competition among sprouts, and therefore an increase in the size variability of these sp routs.