Technology Roadmap: Lumber and Value-Added Wood Products
4.20 By-Product Utilisation

Existing Technology

Apart from chips, the main by-products of the sawmilling industry are sawdust, shavings and bark. Short pieces and trim blocks are increasingly recovered and finger-jointed into high-quality products (see Section 7.3.2 on Finger-jointing). Sawdust and shavings represent the main raw material for particleboard and MDF manufacturers.

In the larger mills, sawdust and planer shavings are mainly used as fuel for energy production. Companies equipped with dry kilns have large energy needs, and wood by-products are an abundant and economical source of fuel. Smaller mills do not have access to wood combustion technology adapted to their needs.

Bark, which represents about 10 percent of the fibre volume processed by a sawmill, has been an ongoing concern for industry. Traditional methods for bark disposal, like open-air burning and landfilling, have been banned in many regions for environmental reasons. Bark can be used as a fuel, and several companies have been marketing pellets made from bark for domestic heating purposes. In recent years, new applications have appeared, such as soil conditioning and compost (from ground bark) and landscaping (from cedar or hemlock bark, for example), but very large volumes continue to be available, and there is an urgent need to develop major applications. Some companies have explored the production of methanol, ethanol or other chemicals (for example, "green" phenols); so far however, such projects have generally had difficulty competing with production facilities using natural gas feedstock, pulp waste (black liquor) or even agricultural products.

A panelboard has been developed from bark, and it may hold potential for converting bark into a marketable product. Several on-going scaled-up pilot plant trials are aimed at developing new patented bark board products. These products cover both structural and non-structural applications. Successful commercialisation would lead to a new family of value-added, environmentally-friendly products from bark.

Incremental Technological Innovation

• Pursue the development of bark boards and other products from bark.