INFLUENCE OF FIRE AND TREE-FELL ON PHYSIOLOGICAL-PARAMETERS IN QUERCUS-ILEX RESPROUTS

Variations in the physiology of two kinds of resprout (originated afte r fire and after tree-fell) of Quercus ilex were analyzed under field conditions and compared with respect to the original, undisturbed vege tation, located within a Mediterranean watershed (northeast Spain). Re sprouting vegetation of Quercus ilex after fire or after tree-fell sho wed, during the next growing seasons, enhanced photosynthesis, leaf co nductance and Rubisco activity with respect to the original vegetation , especially under high temperature, irradiance and vapor pressure def icit (VPD). The lack of differences in nutrient (N,C,P,K and Ca) and s oluble carbohydrate concentrations in leaves of resprouts originated a fter fire or after tree-fell indicates the independence of nutrients r eleased by the action of fire and the contribution of underground orga ns. Differences in leaf mass per area (LMA) were due to increased thic kness in resprouts whereas density was the same. N investment in chlor ophylls or Rubisco was not different in control or either kind of resp rout. The increased amount of carotenoids in resprouts contributed to providing protection from photoinhibitory processes.