SEEDLING REGENERATION OF 2 CISTUS SPECIES AFTER EXPERIMENTAL DISTURBANCES

The regeneration process of two Cistus species (Cistus ladanifer and C istus laurifolius) was compared during the first four years after cutt ing, burning and ploughing in experimental plots, in Leon province (NW Spain). In the burnt plots, a quicker germination, followed by a high er death rate, was observed, especially for Cistus laurifolius. The nu mber of seedlings tended to stabilize after one year in all experiment al plots. During the whole study period, the burnt plots showed a high er number of seedlings. The ploughed plot presented the lowest number, while the cut plots kept intermediate values. The differences in cove r values were not so marked in the different plots and, in the fourth year, there is still a tendency to increase. Neither the cover nor the height of the seedlings have attained the values they had before dist urbance. By comparing the two species for the same disturbance, we fou nd that the cover and height values were similar, but the number of Ci stus ladanifer seedlings was higher. This fact can probably not be con sidered as a direct consequence of disturbance, as this difference was also observed previously.