Wood Preservatives: New Report Explores Directions and Possibilities

A new report has just been published: Wood Protection Research Council, Research Priorities 2013

In this report, authors Carol A. Clausen, Frederick Green III, Grant T. Kirker, and Stan T. Lebow report on findings and recommendations from the Wood Protection Research Council.

Why wouldn’t a homeowner want to build with wood? Sometimes homeowners do not select wood as a building material because of its vulnerability to biodeterioration by fungi and insects under certain conditions of storage and use. These limitations are also a prime cause of user dissatisfaction. Therefore, efforts to protect wood from biological degradation are among the earliest research at the Forest Products Laboratory. This research has successfully reduced the demand for lumber from our National Forests by reducing the need to repeatedly replace existing wood products.

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The cycle of wood harvest, research, and use protects our natural resources.

Wood protection has undergone dynamic changes since the industry voluntarily withdrew chromated copper arsenate (CCA) from most residential uses and new products were introduced to the marketplace. According to the Environmental Protection Agency (EPA), “CCA is a chemical wood preservative containing chromium, copper and arsenic. CCA is used in pressure treated wood to protect wood from rotting due to insects and microbial agents. EPA has classified CCA as a restricted use product, for use only by certified pesticide applicators.”

Obviously, alternatives for wood protection are needed. However, to bring a new preservative to the marketplace, a considerable amount of performance data needs to be obtained. Current laboratory methodologies to determine the durability of test specimens are insufficient, and long-term field testing is required to ensure that a treatment is effective.

Improved accelerated test methods to predict performance would reduce the time needed for the development and acceptance of new preservatives. Potential improvements for accelerated testing may include selection of test fungi, techniques to detect incipient stages of fungal decay, methods to properly assess durability of wood plastic composites use of rapid laboratory bioassays for screening, and field tests that could measure loss in mechanical properties and statistical analysis.

Possibilities and research opportunities abound. For instance, protection systems could be targeted to specific problems. With nanotechnology at the forefront, novel advances in wood protection could replace the broad spectrum biocides traditionally used to inhibit decay fungi. The most logical approach to develop targeted biocides is to take advantage of unique physiological attributes of decay fungi, such as their ability to sequester metals through production of oxalic acid or natural tolerance to preservatives. Discerning and describing these mechanisms may enable us to design specific, targeted inhibitors to control decay and circumvent preservative tolerances that are common in brown-rot basidiomycetes.

This report summarizes presentations and comments from the inaugural Wood Protection Research Council meeting. Research needs for the wood protection industry were iden­tified and prioritized. Methods for successfully addressing research needs were discussed by industry, academia, and association representatives.