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Saproxylic insects are regarded as effective indicators   of   woodland   biodiversity. Consequent ly,  it is  the most  mature and untouched tracts of woodland that house the most complex and diverse communities of saproxylic insects.

Woodland in Gipuzkoa has been subjected to a great deal of human intervention and has been transformed to a high degree, thus falling some way short of the aforementioned maturity.

However, studies carried out to date (Martínez de Murguía et al, 2003; Martínez de Murguía et al, 2004; Martínez de Murguía et al, 2007; Pagola, 2006; and Pagola, 2007) reveal that Gipuzkoa’s woods are home to a diversified community of saproxylic insects, among them some species of considerable interest, which goes against the findings of previous studies.

According to these studies, this is largely due to the presence of a specific tree type, namely pollarded trees, which are cut back extensively in order to obtain firewood. This has also led to the increasing use of these areas of land by dairy farmers. This pollarding causes holes and rotting in the wood and also extends the life of the tree.

The recently completed LIFE project “Aiako Harria SCI” also revealed the close links between pollarded trees and the biodiversity of saproxylic species. However, this relationship has been affected by the socio-economic changes that have taken place in the region and which caused the abandonment of intensive pollarding from the 1950s.

Available weighted data shows that there are nearly 150,000 pollarded trees in Gipuzkoa, most of them being beech trees, though there are also oaks, ash trees and chestnut trees.

Only a very small fraction of these trees are currently being managed. As a result their longManagement and conservation of the habitats of *Osmoderma eremita, *Rosalia alpina and other saproxylic insects in Gipuzkoa 1LIFE+ Biodiversity and Pollarding term survival in the region is under threat, which may well have significant consequences for its biodiversity.