Decay indices for evaluating wood decomposition activity

Abstract

The goal of the current study was to evaluate the efficiency of Norway spruce wood decomposition by the saprotrophic fungus Phlebiopsis gigantea (Fr.) Jülich. We identified the following indices as reliable measures of wood decay: decay acceleration index (DAI), final decay index (FD), and decay intensity index (DI). DAI was used to assess acceleration and deceleration of spruce wood loss, FD to estimate the final wood decay, and DI to evaluate the ability of the fungus to decompose wood, taking into consideration changes in mycelial activity over time. We tested the hypothesis that the wood decay activity of any fungus can be evaluated more objectively when: (i) several isolates of the tested fungus are assessed simultaneously, (ii) tests are performed for at least two time-points, and (iii) samples vary in wood density. Allowing a three-month period for wood decomposition was inadequate for reliable assessment of the wood decay ability of P. gigantea. Conversely, six months after inoculation, the tested isolates showed significant differences in their ability to generate dry wood loss, which depended on wood density. In view of these results, the DAI, FD, and DI indices are practical tools for assessing fungal activity to predict wood loss.

KEYWORDS:

• Phlebiopsis gigantea registered isolates
• Norway spruce wood
• decay index

Acknowledgements

The authors wish to thank Dr Marina Niemi (Verdera, Finland) and Dr Kathy Tubby (Forestry Commission, UK) for providing the preparations with P. gigantea registered isolates used in this study.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was conducted as a part of the research project BLP-329 financed by the General Directorate of State Forests, Poland.