Robert Ross & Shayne Martin – USDA Forest Service Forest Products Laboratory
A year ago, the Forest Products Laboratory staff received a unique request.
That request came through a relationship built on cooperative research between the Department of Defense and the U.S. Department of Agriculture Forest Service, Forest Products Laboratory (FPL). This connection resulted in an amazing story of a 3,000-lb stack of legacy mahogany and other vintage lumber of incalculable value being used in the restoration of many historical wood objects at the U.S. Capitol building.
While our country reflects on the attack of January 6, 2021, which resulted in the damage or destruction of many treasured historical artifacts, we also reflect on the story of the wood used to repair what was thought to be irreplaceable. That story shone as a bright light and sign of hope in an otherwise dark situation.
This stack of vintage materials waited for more than 100 years in a quiet, forgotten corner of FPL’s storage facility. But that day, the nearly forgotten stack was called to service. FPL researchers and collaborators mobilized and purposefully bundled and shipped this incalculably valuable legacy lumber to be used in the repair of the U.S. Capitol building. But there is more to this story.
When a tree gets harvested, its ultimate destiny is unknown. It may be used in a wealth of applications—from paper to building materials to the finest furniture.
The species of wood harvested might offer a clue to its eventual destination, but ultimately its final use is up to the lottery of supply chain, human need, and a sprinkling of fate.
In March 1918, during the WWI war effort, the U.S. War Department tasked FPL with an important aircraft research project—the equipping and operation of an experimental propeller plant. The aircraft flown at the time were made entirely of wood—the framing for the fuselages and wings of Sitka spruce from the West Coast, and propellers of hardwoods from the Midwest.
WWI saw U.S. domestic hardwood shortages in high-value, high-quality lumber, the kind needed for reliable propeller operation and performance. Humidity—capricious, variable, and intangible—was one of the problems WWI aircraft designers faced. Propeller performance was critical. Blade instability from warping, twisting, and unbalancing was the hurdle to overcome.
Moisture was set to potentially ground a vital tool in the WWI war effort.
To solve this two-fold problem, raw material shortage and identifying available wood species that exhibited a relatively stable response to moisture movement, FPL researchers broadened their search globally. And under closely controlled conditions, FPL manufactured, stored, and finished experimental propellers from seven species of wood, primarily mahogany, including those found in South America, Africa, and Southeast Asia.
FPL provided research results to the national effort in four areas– kiln-drying, packaging, chemistry, and aircraft. Exact strength requirements were developed for wood airplane parts, and the suitability of different wood species were examined with the goal to maintain or increase strength while minimizing weight. At the time, mahogany was identified as an imported wood that could reliably meet the intense demands of aircraft propellers. FPL established a special laboratory to investigate the problem. Experimental propellers were produced at a rate of 10 a week, a schedule that called for work on a three-shifts-per-day basis. The information discovered was used in the design of propellers.
Lumber that was not used in the research was stored for future work—and dust collected. The stack waited. Time passed. Human lives swirled by. The stack waited—
The stack waited for more than 100 years. Then January 6, 2021 erupted and FPL researchers and collaborators stepped-up in service of the American public and shepherded this priceless stack of legacy lumber to the Capitol.
FPL’s vintage lumber had a long journey through time to reach its final purpose. And although much of the work done by the Architect of the Capitol (AOC)’s skilled carpenters has been closely guarded, we do know that a number of doors have now been completed—waiting to be installed as the doors to our democratic future.
And that’s a legacy FPL takes pride in.
Do you want to know more about the history of FPL’s legacy mahogany? Check back with us in the coming months, a more in-depth report covering the history and research of this project will be published soon.
Valued for its aesthetic and used for millwork, cabinets, molding, flooring, and furniture, many species of Philippine mahogany are now listed by the International Union for Conservation of Nature (IUCN) as endangered or critically endangered due to logging and habitat loss. To find out more about the different species of true mahogany and Philippine mahogany, check out FPL’s 2021 edition of the Wood Handbook.
Curious about the extraordinary contributions our researchers are making to the world of wood science? Please visit the Forest Products Laboratory at https://www.fpl.fs.fed.us/
Contact us about this story or any of our other incredible projects at https://www.fpl.fs.fed.us/news/mediacontacts/index.php