Long before the matsutake mushroom, madrona-bark cream, and nettle-seed dish made it onto Cafe Barjot’s menu in early September, it had been taking shape within chef Nick Coffey’s mind for weeks.

After wildfires ripped through Napa Valley last year, Stu Smith of Smith-Madrone Vineyards was thanking his lucky stars for the trees that somehow dodged damage. But now, a new threat has come.

Many believe the most beautiful of all the native evergreen trees in the Pacific Northwest is the Arbutus menziesii, more commonly called madrona. It has broad, shiny leaves and smooth, red bark, ...