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Factors which influence the performance of alkylammonium compounds as wood preservatives

University of British Columbia

There has been an ongoing debate into the reasons behind the unexpected failure of alkylammonium compound (AAC) treated wood in field trials. The main objectives of this thesis were to investigate wood and fungal interactions with AAC wood preservatives, in order to help answer the question regarding lack of performance. Fixation studies found that ion exchange plays a minor role in the adsorption of AACs in the outer regions of the wood. Both fixation and cell wall distribution studies indicated that AACs preferentially bind onto the lignin. Cellular distribution studies using SEM-EDX showed that several factors influenced the retention and distribution of AACs. These included cell type, wood species, sample size, solution pH and treating concentration. The above work suggests that AAC distribution in the wood has a single weakness. AACs in the earlywood tracheids are prone to leaching and decline rapidly from the outer surface. These characteristics would result in areas without protection against invading organisms. Mobility studies indicated that DDAC depletion in a flooded soil bed study was a combination of both physical leaching and biological effects. Bioassay analysis indicated that standard deteriorating fungi were sensitive to AACs. Field isolations yielded DDAC tolerant Verticillium spp., an Acremonium sp. and Gliocladium roseum. Further studies found that these tolerant organisms could degrade AACs in a wood matrix. This highlights an area of concern where the presence of non-decay fungi, could colonize the AAC-treated wood and may degrade the AACs in the wood to levels inadequate to control wood decay fungi.

Thesis/Dissertation

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2009-06-05

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http://hdl.handle.net/2429/8837

Forestry

University of British Columbia

UBCV

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