The staggering scale of this year’s western wildfire season has driven home in dramatic fashion the consequences of misguided policies informed by a zero-tolerance attitude toward fire. More than a century of fire suppression, combined with drought driven by climate change, has created forests chock-full of volatile fuels and primed for megafires. The result, this summer and fall, has been an onslaught of record-breaking blazes that have devastated communities from California to Colorado. Though it hasn’t made as many headlines, another outcome of our fire-avoidance mentality is devastating ecosystems farther east: Trees are marching across the Great Plains, proliferating in the absence of the frequent fires that once kept them at bay. Despite their many benefits in different settings, eastern redcedar, mesquite, and other woody invaders of the prairie are sucking up precious water, reducing forage for wildlife and livestock, and degrading habitat for fast-declining...