Estimating normative grazing capacity of planted Mediterranean forests in a fire-prone environment

Fire hazard in planted Mediterranean forests can be reduced by appropriate grazing of the combustible under-storey but there is little detailed information available on the forage value of the under-storey vegetation and the stocking rate necessary to utilize the vegetation efficiently. Planted forests are often monitored, mainly to determine the rate of tree growth and sometimes include data on the under-storey vegetation. An algorithm based on the data of such a survey was constructed to calculate a normative carrying capacity of each forest stand for grazing sheep and cattle and browsing goats. Carrying capacity calculated in this way was found to be a fair reflection of actual observed stocking rates. The over-riding factor that determined the forage value of the forest was the relative cover of herbaceous and woody vegetation in the under-storey vegetation. The estimated potential carrying capacity of a representative forest was found to be considerably greater than the number of livestock available for grazing the combustible shrubs and dwarf-shrubs in the forest. This is a common situation in the northern Mediterranean region. Measures are suggested to encourage an increase in the number of livestock needed to effectively reduce the fire hazard in planted forests.