Chemical preservation methods
All commercial wood species in northern Europe have heartwood that has either little or no natural resistance to wood-destroying organisms. When the heartwood becomes wet it’s attacked by wood-destroying fungi and then decays. In many end uses, it will be attacked by wood-destroying beetles and termites. Wood in the sea is susceptible to damage by marine animals and fungi. The sapwood of all species is susceptible to attack by all wood-destroying organisms and by staining fungi.
Where there is little or no natural resistance, wood and wood products are treated with preservatives that protect them from fungi, bacteria, insects, water, weather or fire. This improves the wood’s resistance and conserves its structural integrity.
Wood or wood products treated with wood preservatives can be found in the building and construction sector (wood lattices, bridges, alpine cabins or chalets), in gardening and landscaping (fences, arches), as well as in agriculture (poles for fruit and wine growing), toys and playground equipment, avalanche and noise barriers, railway sleepers and telegraph poles. Depending on its use it is classed in a range from 0 to 5. For use classes 1 to 4, there is an increasing risk of wood becoming and remaining wet and a concomitant increase in risk of fungal decay.
Wood preservation can take place in specialised companies, as a part of the production in sawmills (where sawmills offer not only sawn timber, but also treated timber) or in other wood processing industries, such as window and door production.
In Europe, there are approximately 250 installations with a production capacity of more than 75 m3 per day, and, as of 2021, 110 companies have an active NTR certification.
Source and further reading: JRC Europe
“When the heartwood becomes wet it’s attacked by wood-destroying fungi and then decays.”