Traditionally, many elements of our infrastructure, such as electric power grits, railway networks, guardrails, ports, piles, and bridges – are made of wood. Wood often wins over competitive materials such as steel, concrete and plastics due to its beneficial carbon footprint, sustainable production, and high elasto-mechanical performance at low weight. However, since most infrastructure is exposed outdoors the overall performance of wood infrastructure is also defined by its biological durability against different wood-destroying organisms. To ensure sufficient durability the wood infrastructure requires protection by design, cell wall modification, preservative treatments or a combination of several protection strategies.
In contrast, mass timber is a category of framing types typically characterized using large solid wood panels or beams for wall, floor, and roof construction, but rarely under outdoor conditions. Among other products typical mass timber is CLT (cross-laminated timber), NLT (nail-laminated timber), DLT (dowel-laminated timber), SCL (structural composite lumber) and glulam (glued-laminated timber). Because of its high strength and dimensional stability, mass timber offers a low-carbon alternative to steel, concrete, and masonry for many applications in the building sector. Mass timber is usually made of not or less durable conifer species and thus principally prone to wood degradation when it is exposed to high humidity and moisture. Therefore, wood protection by design is especially important with respect to the building envelope. Moisture accumulation within the building exterior walls needs to be prevented under any circumstances, and still some risk will remain, which may be prevented using biocides. It is a balancing act between sufficient wood protection by design and necessary application of wood preservatives where the latter is not possible.
The International Research Group on Wood Protection (IRGWP; http://www.irg-wp.com) dedicated therefore two special session at its 50th Scientific Conference on Wood Protection, in Quebec City, Canada, to ‘Mass Timber – Protecting its Potential’ and ‘Protecting Wood Infrastructure – Poles, Piles, Ties and Timbers’. Scientists and industry representatives from five continents with background from wood science and timber-, railway- and civil engineering contributed to these special events and covered a range of aspects related to the following topics:
Wood infrastructure:
Economic impact analyses
New techniques for protecting wood from biological deterioration and fire
Research into improved systems for wood protection
Remedial treatments
End-of-life recovery advances & challenges
Up-to-date market data
The competitive advantage of employing best practices
Education & outreach to the next generation of users
Mass timber:
Mass timber protection by design
Building practices, climate and other factors affecting mass timber adoption worldwide
Adapting traditional protection technologies to mass timber
Use of new preservatives and modified wood for mass timber
Monitoring of mass timber
Remedial treatments for mass timber
Life cycle assessment of mass timber
Other items or perspectives
The research contributions selected for this issue are covering different aspects related to durability and protection of wood infrastructure and mass timber. The recent state-of-the-art as well as actual challenges in research are envisaged and highlighted from different viewpoints.
The International Research Group on Wood Protection is a structured group of like-minded scientists and technologists from industry, academia and commerce focusing on generating knowledge of the science of wood deterioration, and novel solutions to provide sustainably and environmentally responsible products for protection of wood-based materials. Every year since 1969 an international scientific conference has been organized to exchange ideas, information and research findings in the field of wood protection. Topics of high actual importance are regularly addressed in the frame of special thematic sessions.