This story appeared in the May 2020 issue. Subscribe to Discover magazine for more stories like this.
Today, tree-planting campaigns green urban areas and promote healthy spaces. Nonprofit groups work with local governments from coast to coast to raise the profile of city forests, hoping to restore canopy cover and reduce urban heat islands. But imagine if greening campaigns had the urgency of national security: Planting trees is your patriotic duty.
It actually did happen. Valuable natural resources like oil or iron o en get government support, but during World War II, trees also fit the bill — specifically, cork oak trees.
Cork had enjoyed commercial value for centuries, of course, in wine bottles and fishing equipment, among other uses. But during the first half of the 20th century, the spongy material from the bark of the cork oak (Quercus suber) gained much wider use as an industrial sealant and ...
