A Story Around Every Corner

In a place as old and interesting as the Forest Products Laboratory, there are unusual stories lurking around every corner. Literally.

Today’s find: a curious collection of boards hanging on a wall in what used to be FPL’s wood preservation plant.soak1

According to several people in the Durability and Wood Protection unit (who all attested this research happened WAY before their time), the story behind the boards goes something like this: Years ago, farmers wanted treated wood for fence posts but often didn’t have access to (or couldn’t afford) commercially available pressure-treated wood. Instead, they simply soaked wood in barrels of preservatives and hoped for the best.

Presumably in response to this common practice, a study was conducted at FPL to compare different wood species and determine how well they retained preservatives through soaking.

soak2Twenty-seven boards make up the display, each adorned with a warped, stained paper label announcing their scores. Yellow buckeye was the champ, with a retention of 13 pounds per square foot (lb/ft²). A board labeled “arsenic-killed jack pine” comes in second at 11.2 lb/ft².  Arsenic-killed refers to the once-common practice of girdling trees and applying arsenic to the cut, making them much easier to debark.

Balsam fir was the loser of the group, retaining only .2 lb/ft² of preservative. Englemann spruce, green jack pine, and tamarack weren’t much better, all measuring below 1 lb/ft².

Sycamore, longleaf pine, cottonwood, and incised aspen (meaning slits were cut in the wood to increase absorption) rounded out the middle, each soaking up 6.5 lb/ft² of preservative.

Pressure-treated lumber, now relatively common and easy to find, not to mention highly regulated, has replaced these DIY approaches to wood preservation. This research, however, shows that FPL scientists have maintained a tradition of testing common practices to provide scientific evaluation and practical feedback.