Pinus halepensis (Aleppo pine), is the dominant tree of a large fraction (26%) of the Greek coniferous forests; this species is an endemic pine of the Mediterranean Rim and well adapted to fire. Its regeneration is accomplished exclusively through seeds, thus its soil and canopy seed banks are of paramount importance for postfire resilience. Cone opening and seed dispersal were investigated in unburned forests of Attica (Greece) and it was found that Pinus halepensis trees maintain a significant percentage of the yearly cone crop (40-80%) closed, thus creating a persistent, canopy seed bank. Full viability of enclosed seeds was maintained for at least three years in canopy storage; moreover, preliminary results concerning the viability of seeds enclosed within the cones for four to more than 50 years showed a gradual reduction of both final percentage and rate of germination. Nevertheless, cones of up to 20 years of age contained a considerable fraction of germinable seeds. On the other hand, Aleppo pine forms only a short-lived (transient) soil seed bank; this bank was particularly abundant after a fire, as a result of the fire-induced cone opening. The germinable seed portion, although quite important prior to the start of the rainy season, was rapidly depleted, and at the end of the rainy season it was virtually absent in both burned and unburned forests. It is therefore concluded that postfire Aleppo pine seedling recruitment takes place almost exclusively during the first year after the fire and depends upon the germination of seeds in a transient soil bank which is produced by the postfire dispersal of pine seeds stored in the canopy seed bank.

The post-fire regeneration of a 45-yr-old Pinus halepensis (Aleppo pine) forest, burned in July 1989, has been studied on Mount P h i s , Attiki, Greece. Four experimental plots at various slopes and exposures were established at altitudes of 400 -450 m, and monitored for 3 yr at 3-month intervals. Early regeneration took place abundantly, through both resprouting and seed germination of mostly hard-seeded herbs and shrubs; the floristic richness was high with 80 taxa. Pine seedling emergence took place during the winter of the first post-fire year. The mean pine seedling density by the end of the recruitment period (March 1990) was 5 -6 seedlings/m2. This density decreased slightly during late spring and considerably during summer. During the second post-fire year only a relatively slight decline was observed; thereafter the density was stabilized to 1 -2 seedlings/m2. Mortality follows a negative exponential curve that levels off at ca. 20 ' %. Height distributions throughout the three post-fire years were all positively skewed as a result of the presence of few very tall saplings. A considerable fraction (20 %) of very short (5 -15 cm) saplings were still alive 39 months after the fire; these may constitute the sapling bank. Based on the analysis of height distribution curves, it is concluded that the taller seedlings survived significantly better than the shorter ones.

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