An imbalance of mature white oaks growing in US forests poses a long-term threat to the bourbon industry, which uses them to age the spirit in barrels. And brands like Makers Mark are taking action before it's too late. Modern Farmer explains the issue, which boils down to the 90 years it takes an oak tree to mature. With 75% of the 100 million acres of white oaks at prime maturity (along with high demand for their wood in carpentry), regeneration of the slow-growing trees will see rapid decline if business continues as usual. White oaks are hardy trees that generally fare well in drought and forest fires, but a laissez faire approach to forestation, with less controlled burning, has left them vulnerable to faster growing trees that block out sunlight.
"White oak is a very slow growing species, and we are cutting at least 1 million of these trees every year just for Kentucky bourbon barrels," says environmental activist Dave Cooper in a Lexington Herald-Leader op-ed. He notes that one white oak tree makes up to two barrels, which by industry standards can only be used one time. Most bourbon (95%) is made in Kentucky, where 2.6 million barrels were filled in 2021 alone. If you're wondering why oak is so important to the spirit, one of the strict rules in bourbon making (i.e. it can only be distilled in the US) is that it's aged in a new oak barrel. Otherwise, it's not bourbon.
Now that the bourbon industry has been put on notice, brands are stepping in. The University of Kentucky partnered with Makers Mark in 2021 to create America's largest repository of white oaks. Since then, they've planted thousands of trees at the brand's Star Hill Farm in Kentucky. But mass isn't their sole mission. The groups are looking to find a kind of super tree in the hundreds of varieties they've planted by labeling them, then sourcing acorns from the top growers. They're also mapping the genome of the "mother tree," a white oak between 300 to 500 years old that will help researchers understand longevity and disease resistance. Other whiskey companies, including Sazerac and Brown-Forman, have conservation projects underway as well to ensure the future of their barrels.
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Forestry professor Calvin Norman tells Bloomberg on the New Lots podcast (via Whiskey Raiders) that bourbon barrels can only be made by the highest quality trees that grow completely straight—and knots or splits will create leaks. He says conserving them creates forests with more biodiversity since white oaks do not create a light-blocking tree canopy, allowing other species to thrive. "There's a higher diversity of [butterflies] that use oak for their larval stages," he says. "There's a lot of caterpillars; that means there's a lot of birds and bats that clean those caterpillars off of the oak foliage." (In the beer vs. whiskey debate, spirits have pulled ahead.)
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