Quantità e qualità delle produzioni sughericole regionali

The cork oak forests are classified by Land Use Map of Sardinia in three different classes: cork oak forest with tree cover greater than 25% (84.873 ha); cork oak forest with tree cover between 5 and 25% (53.070 ha) and mixed forest where cork oak tree cover is greater than 20% (355.143 ha). The species therefore affects 20% of the region. The major area of pure cork oak stands is localized in central-north Sardinia (Nuoro, Olbia- Tempio and Sassari provinces each one with 24.000 ha and 14.000 ha of the first and second type of cork oak forest respectively). Between 1998-2005 the forest fires affected 1,9% of regional surface and 4,6% of forest regional surface, being the cork oak forest 21% with 1.216 hectares annually fired. The only Olbia-Tempio Province registers a positive rate between cork oak forest fired and reforestation (+1.231 ha in the last eight years). The structure of cork oak forests in central Sardinia is low influenced by environmental factors while it might depends on grazing and management decisions of owners. For these reasons the production can be vary in a large range from 1.0 to 6.4 t·ha-1 but always with a stripping height lesser than permitted value by regional legislation. Regional yield, estimated nearly 12.000 t per year, meets about half of industrial requirements. The debarking recording, carried out by regional C.F.V.A. in five important producing areas during 2000-2006, shows a forest yield variable between 28 (Nuorese) and 107 (Central Southern Sardinia) kg·ha-1·anno-1 for reproduction cork. The prime cork quality analysis from the cork seven main production areas of Sardinia showed relationships between quality cork properties, graded by an independent panel of experts, and elevation site, sand and phosphorus content in soil. The best cork quality is distributed in centre-north (Logudoro-Goceano) and south-west (Iglesiente) of Sardinia, but it is linked together with a negative too small thick.