Preserving Wood’s Integrity: The Science and Strategies of Wood Treatment and Protection

Enhancing Durability: Overcoming the Challenges of European Wood Species”

Many European wood species, locally available as building products in Europe, have heartwood with insufficient or no durability, making them particularly susceptible to damage from wood-destroying organisms.

Heartwood with insufficient or no natural resistance will decay (attacked by wood-destroying fungi) when it becomes and remains wet. It will be attacked by wood-destroying beetles and termites in many end uses. 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.

Most sawn wood used for building products includes both heartwood and sapwood and even if the heartwood have some natural resistance the sapwood part have no resistance and will be attacked first and then spread.

Picture 1: The inner heartwood and outer sapwood: Sapwood have no resistance (all species).

Safeguarding Wood: The Role of Preservatives

Where the natural protective constituents are insufficient or totally absent, wood and wood products are treated with preservatives to protect them from the damaging effects of fungi, bacteria, insects, water, weather or fire; providing long-term conservation of structural integrity and improving the resistance.

Picture 2: Preservatives used to enhance wood’s resistance to environmental threats.

From Construction to Playgrounds: The Wide Use of Treated Wood

Wood or wood products treated with wood preservatives can be found, for example, in the building and construction sector (wood lattices, bridges, alpine cabins or chalets, etc.), in gardening and landscaping (fences, arches, etc.), as well as in agriculture (poles for fruit and wine growing), toys and playground equipment, avalanche and noise barriers, railway sleepers and telegraph poles.

Picture 3: Versatile applications of treated wood: Ensuring durability and safety in diverse environments.

Understanding Use Classes: Assessing Wood’s Risk to Decay and Moisture

Depending on where the wood is used, use classes in a range of 0 to 5 are defined. 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.

Picture 4: Combatting deterioration by knowing the Use class: The challenges of preserving wood in different use environments.

The Science of Wood Preservation: Methods and Industries

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, e.g. window and door production.

Picture: Inside a wood preservation facility: Where the transformation of wood takes place.


  1. Low Durability of European Woods: Locally available European wood species often have heartwood with low durability, making them more vulnerable to decay and pest damage.
  2. Widespread Susceptibility: Both heartwood and sapwood are susceptible to attack by wood-destroying organisms, especially in wet conditions.
  3. Essential Use of Preservatives: Preservatives are crucial for protecting these vulnerable woods from damage due to fungi, bacteria, insects, and environmental factors.
  4. Diverse Applications: Treated wood is used in construction, gardening, agriculture, and other sectors, with specific use classes indicating risk levels.
  5. Preservation Techniques: Wood preservation is vital in industries like building and agriculture to enhance the durability of European woods with naturally low heartwood durability.

Fact Box:

  • European Wood Species: Many species used in Europe have heartwood with low natural durability, making them more prone to damage.
  • Heartwood and Sapwood: Central sections of a tree trunk, with heartwood being denser but less durable in European species.
  • Wood-Destroying Organisms: Pests and fungi that pose a greater threat to European woods with low durability.
  • Preservatives: Chemical treatments used to protect these vulnerable woods from environmental threats and decay.
  • Use Classes: Categories indicating the risk of decay, especially important for European woods in construction and other applications.
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