Trees provide the primary raw material for the European pulp, paper and board industry. Wood is made from cellulose fibres that are bound together by a material called lignin. In a pulp mill, the fibres are separated from one another into a mass of individual fibres. This is called woodpulp. The separation can be undertaken by a mechanical process, where the fibres are teased apart or by chemical means, where the lignin is dissolved away by cooking the woodchips in suitable chemicals. After separation the fibres are washed and screened to remove any remaining fibre bundles. The pulp may then be used directly to make unbleached papers, or bleached for white papers. Pulp may be fed directly to a paper machine in an "integrated paper mill" or dried and pressed into bales to be used as a raw material by papermills worldwide. No two species of tree produce the same grade of fibre. In fact, the same species grown in different parts of the world show different fibre properties. For example, the slow growing pines of Northern Europe produce long fibres which give the strength and long life essential for packaging and high grade printing papers. The shorter fibres from rapidly growing deciduous trees grown close to the Equator are lower in strength, but have other qualities suitable for different products. Some of the pulp properties depend upon the procedure used to separate the fibres from the timber.

Mechanical Pulping Chemical Pulping Thermo-Mechanical-Pulp and Chemi-Thermo-Mechanical-Pulp Source of Fibre for UK Papermaking

What is Wood Pulp? The British Wood Pulp Association