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Individual Highlight

Investigating the Role of Moisture in Durability of Acetylated Wood

Photo of The relationship between mass loss and moisture content at end of tests, each horizontal was calculated using different methologies. The top row represents the traditional approach (mass loss), the second row represents mass loss corrected for fungal growth, and the bottom row represents mass loss corrected for moisture production due to fungal metabolism. This figure highlights the difficulties in separating interacting effects in studying acetylated wood.The relationship between mass loss and moisture content at end of tests, each horizontal was calculated using different methologies. The top row represents the traditional approach (mass loss), the second row represents mass loss corrected for fungal growth, and the bottom row represents mass loss corrected for moisture production due to fungal metabolism. This figure highlights the difficulties in separating interacting effects in studying acetylated wood.Snapshot : FPL researchers join international effort to investigate fungal decay resistance of acetylated wood.

Principal Investigators(s) :
Kirker, Grant T.Bishell, Amy B.
Glass, Samuel V.Zelinka, Samuel L.
Research Location : Forest Products Laboratory, Madison, WI.
Research Station : Forest Products Laboratory (FPL)
Year : 2020
Highlight ID : 1673

Summary

Acetylated wood is the most common form of modified wood in the world and is gradually gaining acceptance in the US as a form of wood protection. Acetylated wood is less prone to dimensional shrinkage and also exhibits increased resistance to fungal attack. The exact mechanisms of fungal resistance are not fully understood but has been a focus of the bio-deterioration research community for several decades. However, moisture exclusion has been studied extensively as a potential mechanism. Past research has indicated linear relationships between level of acetylation (expressed as weight %gain or WPG), wood moisture content, and mass loss due to fungal decay. In a recent special issue of the journal MDPI Forests, an FPL laboratory study aimed at investigating the effects of moisture on brown rot fungal resistance of wood acetylated to various levels was presented. The goals of this study were to investigate if the observed reduction in decay of acetylated wood was solely due to the reduction in moisture content or if there are additional anti-fungal effects due to the modification. An important finding of this study was the determination that fungi actively confound laboratory measurements of mass loss in acetylated wood because they accumulated biomass during the process and also produce water as part of their metabolic process. These observations will be used to inform and direct future studies aimed at identifying durability mechanisms of acetylated wood.

Forest Service Partners

External Partners

  • None
  • Accsys Technologies