New method for studying the influence of light degradation on the fungal colonization of wood

19 June 2017

Wood, when exposed to weathering, is damaged by its environment. Photodegradation (degradation by sunlight) and biological degradation are recognized as important factors affecting the durability of the material. Until recently, these two phenomena have always been studied independently in the laboratory. As a result, the combined effect of these two factors could not be taken into account. The separate study of these two types of degradation does not represent the reality of normal exposure to the elements, where all degradation factors act at the same time.

The purpose of this research within the Renewable Materials Research Center and the Industrial Research Chair in EcoResponsible Wood Construction was to study the combined effect of these factors from a fundamental point of view via a multidisciplinary approach combining the fields of microbiology and wood chemistry.

Samples of white spruce (Picea glauca (Moench) Voss) were photodegraded for different times under a xenon lamp and then inoculated with black-spotted fungi: Aureobasidium pullulans or Epicoccum nigrum.

It was possible to visually study the colonization since this fungus causes the affected wood to become black. The more coloured the samples, the stronger the colonization.

This work highlighted the amplification effect of photodegradation on the colonization by the fungi. Thus the longer the exposure to light, the more rapid and strong the colonization. It was interesting to note that photodegradation was not an essential factor for colonization. In fact, some wood samples were found to be colonized in the absence of exposure to light.

The method developed revealed an interaction between photodegradation and biological degradation. New protocols can now be developed in order to gain a better understanding of the phenomena involved when wood is exposed to the environment. It is through the acquisition of new knowledge that new wood protection systems can be conceived.

To learn more, consult the Research Note


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