The cellulose pulp is obtained from wood through different processes. However, all processes start from wood trunk or chips, small pieces of wood obtained from the processing of timber by-products. In case the whole trunks are being processed, after being stripped, they get chopped or grounded, to reduce the wood to a suitable size for subsequent processes. The three main production chains of pulp are the sulphate cycle (about 80 %), the sulphite cycle and the semichemical process.