COMPARISON BETWEEN THE SOIL SEED BANKS OF A BURNT AND AN UNBURNT QUERCUS-PYRENAICA WILLD FOREST

Soil samples from burnt and unburnt sites dominated by Quercus pyrenai ca Willd. forests in Leon province (NW Spain) were collected, separate d into an upper layer (0-2 cm depth) from a lower layer (2-5 cm), put in a greenhouse, and seeds allowed to germinate. A total of 670 identi fied seedlings comprising 56 species and belonging to 24 families were recorded. Most seedling were herbaceous perennials (hemicryptophytes: 59%), followed by annuals (therophytes: 23%). Many species that germi nated from buried seeds were not observed as plants at any site, and c ame from exogenous communities. The principal means of seed disseminat ion were anemochory (45%) and autochory (23%). The number of species a s well as seedlings was not significantly different between soils from the burnt and unburnt sites, but seedlings were more numerous in samp les from the unburnt sites, as the number of seedlings was always high est in the upper soil layer. Germination behaviour of four particular species was characterized. Seedlings from the seed bank temporarily we re found in the early stages of recovery of the burnt Quercus pyrenaic a forests.