The drought is currently the phenomenon that puts the great forests of oaks Iberian at greater risk. It is possible to detect two forms of drought, one that produces a sudden death of the tree in a few weeks and another that produces a slow decay drying the peripheral branches to finish drying the tree.
The process is complex and it is unclear origin, it might be involved fungi such as Diplodia sp. Hypoxilum mediterraneum and Phytophthora cinnamomi.
Climatic factors also appear to influence, and according to some authors, the improper handling of bodies of Quercus, in most cases occurs more markedly in the pastures with cattle form. Now there is no effective solution taking into account the particularities of these trees of very slow growth and its distribution in large masses in the Iberian Peninsula affecting hundreds of thousands of hectares.