Structure and composition of pole-stage stands developed in an ancient wood pasture in central Spain

El Chaparral de Montejo is a woodland area situated in central Spain containing a large group of temperate species that since the Middle Ages has been subject to communal use for grazing like many other European forests. We studied the characteristics of former wood-pasture and the pole-stage stands developed close to ancient trees in three representative stands consisting of Fagus sylvatica, Quercus petraea and Quercus pyrenaica. The Fagus sylvatica stand proved to be the best regeneration site because of its deep soil and greater number of ancient trees, which provided more seeds and tree cover, both favouring the development of seedlings in this stand. However, the poorer soil conditions and the dense layer of herbaceous vegetation in the Quercus pyrenaica stand have inhibited the establishment of the more water-demanding temperate species. It is suggested that past irregular exploitation conducted to a mosaic distribution of forest communities explain the differences in structure and composition found in the three stands studied. The stand occupied by the more xerophilous species, Quercus pyrenaica, was more affected by the reduction of forest productivity in the past. Nowadays the patterns of pole-stage stand diversity reveal the future expected changes. The higher diversity of saplings in the Quercus petraea and Quercus pyrenaica stands reveal better conditions in the understorey than those existing in their early developmental stages, especially for the two shade-tolerant species, beech and holly. On the contrary the lower diversity of saplings in the Fagus sylvatica stand is due to the low light levels in the understorey which gradually cause the disappearance of shade-intolerant species.