Emerald ash borer (EAB), a beetle from Asia that feeds on ash trees, was discovered in North America over a decade ago. Land managers estimate EAB has killed hundreds of millions of ash trees in 27 states. To manage EAB, the U.S. Department of Agriculture is using biocontrol, a sustainable management approach that involves introducing specialized insect natural enemies from a pest’s native range. The Forest Service’s Northern Research Station, Agricultural Research Service, and university researchers are studying the impacts of EAB and biocontrol on ash survival, growth, and regeneration at long-term study sites in Michigan. Although most mature ash trees soon died from extensive EAB damage at these sites, the researchers confirmed establishment, spread, and suppression of EAB populations by the introduced natural enemies. More recently, they found that young ash trees are regenerating rapidly from seedlings, stump sprouts, and saplings in Michigan forests recovering from EAB outbreak. They also found one of the introduced natural enemies prefers attacking EAB in these young ash trees, thereby reducing EAB damage. Less EAB damage allows young ash trees to remain healthier and better able to counteract subsequent EAB damage through plant resistance. These findings indicate that biocontrol will improve ash tree regeneration in North American forests.