The phenomenon of creeping plants: an obstacle to the regeneration of cork oak in Tunisia

Abstract: Given the difficulty of natural regeneration, assisted regeneration by planting was adopted as a solution to attenuate the decline of Tunisian cork oak. However, observations made in the planted perimeters with cork oak revealed a phenomenon that hinders the growth in height: the presence of creeping plants, without apical dominance during several years. Our study aimed to estimate, for the first time, the extent of this phenomenon and to find explanations in order to propose solutions. In 6 perimeters, planted between 1995 and 1999 and visited in 2013, the survival rate has been assessed and the percentage of creeping among living cork oak seedlings was determined. A dendrometric characterization of these perimeters was performed. The average survival rate, estimated at 77%, varies from 34% to 100% depending on perimeter. The percentage of creeping plants varies between 18 and 100%, result which reflects the extent of this phenomenon. Hypotheses have been advanced to explain this phenomenon and treatments will be tested in an attempt to reduce its extent.