Evaluation of the thickness and quality of reproduction cork in the cork oak forest of Bellif, northwest Tunisia

Abstract: Despite the economic importance of cork, research on its production and quality is rare in Tunisia. In order to improve the management of the reproduction cork production, cork growth and quality were assessed in the Bellif forest, located in the north west of Tunisia. 16 plots were selected and 5 trees were sampled in each one. The study was carried out on cork plates of 20×20 cm, collected from the sampled trees. The porosity was measured by direct observation of lenticels through a magnifying glass. Density, moisture content, thickness and annual increment of cork were determined. The cork mean thickness was estimated to 41.4 mm. More than 50% of the samples belonged to suitable commercial capping classes (above 27 mm). The cork samples present a high mean density equal to 296.15 kg/m3 which decreases their quality. Analyzed samples of cork are classified in the category of regular, medium porous cork, characterized by the presence of yellow stains.