Vigour of Post-Fire Resprouting by Quercus Coccifera L.

Abstract

(1) Experiments were carried out on Quercus coccifera in southern France to examine the effects of age of stand, fire intensity, fire season, and prefire canopy structure on the vigour of resprouting. Eighteen experimental treatment combinations were tested. Three ages since last fire, three fire intensities, and two seasons were combined. Each treatment combination was repeated six times on plots of 50 x 50 cm. (2) All plant material was clipped, dried, and weighed. Q. coccifera was divided into hierarchical size-classes of basal and branch diameter. The plots were then burned using flame torches. The density and height of each Q. coccifera resprout was recorded through eight weeks following the burn treatments. (3) Significant differences in effect were found between plots of different ages, and between burns of different durations, but season is the dominant variable in all analyses: resprout density and growth are much greater following burning in late May than after burning in early October. Other than season, it is pre-fire canopy structure that most affects resprout vigour. Pre-fire stem density and woody and foliar biomass seem to be important variables, but definitive answers are precluded by high multicollinearity. (4) Path analyses support the hypothesis that resprout density is affected most by prefire stem density. This may indicate a reservoir of dormant meristematic tissue. Resprout growth is more strongly affected by pre-fire biomass value, indicative of underground carbohydrate reserves. More vigorous sprouting follows the spring burn, indicating either greater reserves following the flush of spring growth (compared with depleted condition following the dry season) or, more likely, the direct effect of warmer temperatures and increasing sunshine.