The antibacterial properties of wood should be leveraged in construction

The ability to bind moisture, the beneficial acoustic properties and thermal conductivity are well-known properties of wood, but now researchers are becoming interested in wood’s antibacterial properties. For example, a comparison of cutting boards found that wooden boards repelled bacteria better than their plastic equivalents.

— Many materials contain volatile organic compounds, also known as VOCs, which are considered to be health hazards. Wood’s volatile compounds have been found to have some antibacterial effect. According to studies however, the scent from many wood compounds is harmful to bacteria but not humans, says Tiina Vainio-Kaila.

Vainio-Kaila, who received her doctorate on the subject, has compared how well bacteria survive on untreated wood surfaces when compared to glass, which is traditionally considered hygienic. — When the amounts of bacterial growth on different surfaces were cultured and compared in a laboratory, both e. coli and listeria bacteria gradually died on the wood surface, but survived on the glass plate serving as a control.

— Wood extracts have also been found to be reasonably effective against hospital bacteria. It can be said that wood surfaces and many wood compounds have antibacterial properties and that pine has a slightly larger antibacterial effect than spruce. Many of the dozens of different wood extracts have been found to have antibacterial properties as the lignin that binds the fibres together has an antibacterial effect. In addition, wood surfaces dry quickly; this dryness puts bacteria at a disadvantage.

Vainio-Kaila points out that there has been very little research in general into the effects of wood on well-being. For example, surveys of residents conducted in wooden apartment buildings indicate that the scent of wood is not considered unpleasant and that a wooden building does not cause allergies in residents in the same way many other materials do.

According to Vainio-Kaila, the underlying antibacterial qualities of wood do not come from a single substance but are the result of a well-functioning whole of many substances. — If a change of materials can slow down the spread of hospital bacteria, we should seize the opportunity.  Now that antibacterial research on wood has begun, it would be a good idea to properly study the effects of antibacterial wood in hospital and day-care building materials.

There are already some practical applications that leverage wood’s antibacterial properties. — For example, the German company Wilms HygieneHoltz manufactures a variety of hygiene products from wood, ranging from skin creams to anti-bacterial rugs and cutting boards. They have improved wood’s inherent antibacterial properties in their products even more. Here at home, a Finnish company has launched a sap-based antibacterial salve.

Vainio-Kaila points out that all parts of a tree have medicinal uses. — If antibacterial materials can be used in contact surfaces in public spaces, we will reduce the transmission of various infectious diseases spread by hand. There are many insights and practical applications that can be developed from these antibacterial properties. The only limit is in our imaginations.

This article is part of a series by Markku Laukkanen and Mikko Viljakainen. The series presents a variety of best practices and trends in the Finnish wood industry. The aim is to spread information about best practices and solutions in the Finnish wood industry to increase its competitiveness and make Finnish expertise more widely known. The articles will be published in Finnish and in English. They will be made freely available for use as source material and for publication as they are. The articles will be distributed as Puuinfo newsletters and will also be published on the puuinfo.fi and woodproducts.fi websites. The article series is funded by the Ministry of the Environment’s Wood Construction Operational Program.