Effects of wildfire season on the resprouting of kermes oak ( Quercus coccifera L.)

Abstract

The resprouting growth of kermes oak ( Quercus coccifera L.) after wildfire, in relation to certain ecological parameters, has been studied. The effect of time of fire incident (beginning versus end of growth season) on growth (height and diameter) of new sprouts was examined. For each time of fire incidents, the influence of aspect (slope exposure), and pre-fire size of parental shrub, on resprouting ability and growth of kermes oak was also investigated. A total of 100 burned kermes oak shrubs were randomly selected on each burnt site: 25 per the main four aspects (north, east, south, west). The number of resprout influences their height and thickness. Three resprouts were kept per shrub, and their height and basal diameter were measured every 3 months for three vegetative periods. Statistical analysis of the data included standard procedures of comparison of means. Both sites comprised shrubs with similar pre-burn dimensions. Height growth showed no particular divergence between the two sites, following a typical sigmoidal tree growth curve, and reaching a maximum at the end of the second vegetative period. Height measurements showed highly significant differences between the two sites during the first two trimesters only, while differences in diameter were significant during the whole measurement period. Same-ages resprouts of Site 2 showed a faster initial height growth than those at Site 1. After the age of 12 months, however, height growth was more or less the same at both sites. Differences in aspects (orientation) were found only in plants of Site 2. Height and diameter of new resprouts were positively correlated to height of maternal sprout. Analysis of climatic data identified precipitation as the decisive factor in resprout development. The results of the present study conclude that the date of occurrence of wildfire does not affect the final dimensions of kermes oak shrubs, but it does affects initial growth rate. There are some differences in rate of growth after wildfires occurring at the end of the vegetative period especially relative to aspects. Moreover, after three vegetative periods, shrubs had regained a considerable part of their pre-burn height.