Throwback Thursday: Colorful Solution Saves Time and Money

Red oak and white oak logs can be difficult to tell apart, but only one group is susceptible to the devastating fungus that causes oak wilt.

In the 1980s, to prevent importation of oak wilt-prone red oak wood into the European market area, all oak logs had to be fumigated before shipment, since it was difficult to distinguish between the two groups. Fumigation was a costly, time-consuming process.

Enter Forest Products Laboratory (FPL) researchers, who developed a quick, simple commercial test that used a chemical solution to separate white oak from red oak.

Researchers found that spraying a 10 percent solution of sodium nitrite on the ends of oak logs differentiates red from white oak by the color that results after applying the solution.

Sodium nitrite test: dark purple to black indicates white oak, orange indicates red oak.

Sodium nitrite test: dark purple to black indicates white oak, orange indicates red oak.

To verify the accuracy of the method, 10,000 oak logs among 17 white oak and 18 red oak species at 30 sawmills throughout the eastern United States were tested. FPL research passed the test with flying (purple and orange) colors!

The tests fulfilled the importation requirements by the European Economic Community Commission, saving time and money.

This and hundreds more interesting historic tales of FPL research can be found in Forest Products Laboratory 1910-2010: Celebrating a Century of Accomplishments.