Technical Note: Effect of Soil on the pH of Treated Wood in Ground Contact


  • Tor P. Schultz
  • Darrel D. Nicholas


The pH of treated wood in ground contact will influence the type and activity of decay and nondecay microorganisms present as well as the solubility and leaching of metallic biocides. To determine the soil effect on the pH of treated wood in ground contact, southern pine sapwood samples commercially treated with five copper-based preservatives along with untreated pine were placed in pots filled with five different soils. The pH of the wood samples after a 12-wk exposure to basic soils increased, as anticipated. However, the pH of wood in acidic soils was more complex than expected with the treated wood pH always greater than soil pH. Two possible chemical mechanisms to explain the nonintuitive results for treated wood in acidic soils are given.


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Research Contributions