Effect of two successive wildfires in Pinus halepensis stands of central Greece

We estimated differences, five years after a wildfire, in soil and vegetation between Pinus halepensis stands that were once burnt (1998) and stands that were burnt twice in a short time interval (1995 and 1998), in the area of Penteli, central Greece. The parameters monitored were the physical and chemical attributes of upper soil layer and the vegetation composition, density and height. The results showed that five years after the wildfire, soil pH did not differ between areas burnt once and twice, while the organic matter was higher in the once-burnt areas. The vegetation composition was similar in the two areas and the dominant species were those pre-existing the fire. On the contrary, vegetation density was considerably lower in the twice-burnt areas. The height of woody species oscillated in the same levels in the two areas. The plant community was composed mainly by resprouting species, like Quercus coccifera, Pistacia lentiscus, or Phillyrea latifolia, and less individuals from seed-regenerated species, like Pinus halepensis, Cistus monspeliensis, and C. creticus. It is suggested that the recurrence of wildfire affected negatively the ecosystem attributes, and contributed to the increased risk of degradation.