ForestHarvest: non-timber forest products in Scotland

 RESEARCH

Case study: Cork

The cork oak (Quercus suber) is a typical Mediterranean tree. Large forests dominated by this species are found in Portugal, Spain and North Africa (Morocco and Algeria), with smaller extents in France and Italy. Cork is the spongy outer layer of the bark, which grows to several centimetres thick and is designed to protect the tree from fire.

Cork's remarkable insulation properties, together with its lightness and flexibility, make it suitable for a broad range of applications. It is used in construction, shoe manufacture and the production of lifebelts, textiles, linoleum, musical instruments and many other products.

• Cork forests are managed by thinning, understorey cleaning and rotational harvesting regimes.
• The trees are barked every 10-14 years, taking great care not to damage the living bark below. This is a skilled activity, which takes place during four months of the year. The loss of traditional skills, combined with a growing preference for permanent employment, has had a negative impact on the industry.
• The cork is processed by boiling, removing the tannic acid and making the material more elastic and pliable.
• Cork from the first stripping of a tree ('virgin cork') is relatively tough, but subsequent strippings yield a higher-quality product. The tree can remain productive for 100 years or so.

World trade

Over 80% of the world's cork comes from Algeria, Portugal and Spain. Portugal once produced over 175,000 tonnes per year, worth some £130 million.

Production, however, is now in decline, and Portuguese production is down to less than 40,000 tonnes annually. This is partly due to increasing use of synthetic substitutes, and partly due to the rising cost of labour.

The decline in cork production has raised concerns over the future of the world's cork forests. These are important refuges for wildlife, including species such as the European Lynx.

World's first SmartWood/FSC certification for cork - July 2005