A tree stands its entire life on the place where the seed landed or the seedling planted. This means that the tree cannot move away from grazing animals, hard weather, fire, insects and other attacks. The trunk and branches of the tree are therefore protected with a resistant outer bark. 
 
The outer bark has a complex and interesting chemical structure. Trees consist primarily of cellulose, hemicellulose and lignin. But in addition to the fibres, the bark also contains fats, wax, terpenes, higher aliphatic alcohols, resin, tannins, simple polyphenols, glycosides, mono and disaccharides, suberine and minerals. These substances give the tree a chemical defence against bacteria, fungus and insects.
 
By grinding or cooking the bark from certain trees, people have long been able to produce poisons, colours, spices and drugs for religious and cultural rites. Historically, even flour made from dried inner bark has also been used for baking bread in times of crop failures. As the inner bark contains a lot of fibre, antioxidants and lacks gluten, a certain content of bark is often used in health food products.

Research is now being carried out at Södra to use new technology to find and extract additional substances from tree bark that can be used for new medicines, pesticides or ecofriendly wood impregnation agents.