Regeneration dynamics of Pinus nigra subsp. salzmannii in its shouthern distribution area: stages, processes and implied factors

This paper analyses whether the natural regeneration of Pinus nigra subsp. salzmannii is seed or microsite limited, studying the spatial and temporal regeneration dynamics of a pine forest located in Sierra of Cazorla (Southeast Spain). For three years, pineseed density on the ground, and emergence, and survival of seedlings were measured. Pineseed and seedling density varied from 877 seeds/m2 and 651 seedlings/m2 in 2000 to zero during the two following years. None of the monitored seedlings had survived by the end of the study. Data were used to estimate transition probabilities between the stages of a model of plant life cycle. The model included the effects of different biotic and abiotic factors on the recruitment output. It was concluded that Pinus nigra regeneration is not seed limited, although pineseed production varied greatly interannually. On the other hand, seedling survival depended mainly on abiotic factors. The success of Pinus nigra natural regeneration in Sierra of Cazorla is basically affected by the spatio-temporal variability of abiotic factors and, particulary, by the summer drought.