The Wisconsin Department of Transportation (WisDOT) uses wooden posts to support many types of signs along state highways. WisDOT currently uses red pine or Southern Pine posts treated with chromated copper arsenate (CCA) and has generally experienced satisfactory performance and service life. However, there are some areas of concern, as well as potential opportunities for diversifying the wood species and preservatives used. Warp is sometimes a problem with the current pine posts, and increased use of locally sourced wood species for the sign posts could decrease transportation costs and potentially benefit Wisconsin industries. Although CCA is a highly effective preservative, it may not be the optimum treatment for alternative wood species. This study reviewed the characteristics of alternative wood species and wood preservatives and evaluated their potential for use in Wisconsin highway sign posts.
Lebow, Stan T.; Ross, Robert J.; Zelinka, Samuel L. 2014. Evaluation of Wood Species and Preservatives for Use in Wisconsin Highway Sign Posts. USDA Forest Service, Forest Products Laboratory, General Technical Report, FPL-GTR-231, 2014; 51 p.