EL SÍNDROME DE LA SECA EN MASAS DE QUERCUS SPP. EN ANDALUCÍA.

In Andalucia, the syndrome known as seca has weakened the Quercus forests with the following appearance of the syndrome’s spots in all its provinces. In order to determine the actual situation of the syndrome in the region a census of the damages caused by the seca has been elaborated. The information obtained from this census has made possible a territorial analysis of the damages in Andalucia that can be useful to define a biogeography of the seca, from a fitoclimatic or causal agents point of view. The interpretation of the information has made possible to characterize three large areas with similar characteristics concerning the syndrome’s incidence: Sierra Morena, the Cadiz-Malaga western sierra and the oriental region of Andalucia. In Sierra Morena and the Cadiz-Malaga western sierra the damages follow a pattern characterized by small to medium sized spots, with a medium to high percentage of affected trees, distributed in a random pattern, and dominance of gradual death of the trees. This reveals the progressive weakening of the forests, probably associated to the region’s tendency towards more arid fitoclimates. However, the Cadiz-Malaga western sierra differentiates due to the hi presence of cork trees (Quercus suber), that adds the cork harvesting practices, origin of many direct and indirect damages, to the incidence of the climatic factors. In the oriental region of Andalucia the pattern of damages differentiates in having larger spots, with a higher percentage of sudden death of trees, and distributed in areas with low water retention soils or where a high thermal accumulation is expected. In this case, the tendency towards more arid fitoclimates is more accented, with a higher incidence of heat-strokes