Portugal is the largest producer of cork in the world (half of the world production). The first postage stamp made from cork  became an obsession for the stamp collectors.  Portugal post office issued also a postal stationary in commemoration to the International Year of the Forest. One thing very particular with cork stamps is that each one is unique as  the pattern of the material is natural (never the same in each stamp).

Cork and the cork oak – national symbols 
Cork. A gift from nature. National heritage. 
Ambassador for Portugal. 

Cork is the bark of the cork oak, a renewable, recyclable and biodegradable natural product. Quercus suber L., planted by mother 
Nature mainly in southern Portugal, forms the essence of the Alentejo landscape’s identity. Home to an endless variety of animal and plant species, the cork oak forest, in its multiplicity of functions, prevents desertification in the southern part of the country, a dry region with thin topsoil, reducing erosion and making an immeasurable contribution to the local economy. The cork oak forest and the cork it produces play in important role in CO2-fixing, the main culprit of global warming. 
Protected by kings and governors from the beginnings of the nation to the present day, the cork oak has always enjoyed the protection of national legislation. The first references to cork and the cork oak appear in the letters of King Dinis in the 13th century. However, cultivation of the cork oak forest as we know it today did not begin until the 19th century. Rough in appearance but pleasant to the touch, cork possesses unique characteristics: it is light, impermeable to liquids and gases, compressible and elastic, it provides excellent insulation against temperature, sound and vibration, and is resistant to friction. Used in a wide range of applications, from construction to the automobile industry and aeronautics, it is in the cork stopper that cork takes its most well-known form. 
Without mentioning the Romans and Phoenicians, who may have used cork to seal their amphorae, it was in France that cork started to be used systematically, by Dom Pérignon, to store the much-prized nectar. It was Portugal, however, that developed the skill and the know-how required to harvest and process it. For historical reasons, linked to the proximity of Port wine production, the industry was established mainly in the North, specifically in the Aveiro district, a region which remains to this day the world centre for processing and sale of cork. An ambassador for Portugal, cork has carried the nation’s name to the five continents and even into space. Today, Portugal is the world leader in cork production, processing and exports. This position has placed Portugal at the forefront of knowledge and research in the area, and has bestowed upon it the responsibility of protecting and promoting this 
noble product of the Mediterranean forest.
Cork and the cork oak have inspired books, poems, songs, fashion, design and jewellery. They are part of Portuguese culture. A symbol that is now enshrined in a prestigious postage stamp. A stamp made of cork, the bark of the cork oak. 

Lisbon, 26 September 2007
Jaime Gama
President of the Assembly of the Republic