MICHIGAN—The demise of chestnut trees beginning in the early 1900s from chestnut blight, the disappearance of elms from the 1930s to the 1970s due to Dutch elm disease, and the recent catastrophic impacts of the emerald ash borer on ash species tell the sad story of how native trees, with few defenses against non-native insects and pathogens, fare in our ever-changing environment.  

In “Backcross,” the most recent season of Forestcast—a podcast produced by the Northern Research Station—host Jon Yales interviews a cadre of Northern Research Station scientists and collaborators who are working on a solution to devastating impacts of pest insects and diseases. But unlike the entomologists featured in season 1, who use chemicals and biological controls to push back against the insects and diseases, the scientists of season 2 are working from the inside out to develop resistant trees that are used in the forest restoration efforts of today.

Developing resistant trees is a complex and lengthy endeavor that often begins by looking for trees that have survived an invasion or disease, and in the case of emerald ash borer, it began by finding the lingering ash trees whose genetic make-up somehow enabled them to survive their initial infestation.  Then begins the time-consuming job of testing for resistance, proactive and collaborative tree breeding, and repeating over and over. Ultimately, through resistance breeding and restoration ecology we can make hardier trees that can better resist pests and pathogens and ultimately provide the planting stock for restoring forests and tree species.  

"Tree species restoration—especially with species that are threatened with extinction—isn't even on the table unless you have resistant planting stock,” said Yales. “That's why, this season, we’ll be crossing back and forth between two types of research—resistance breeding and restoration ecology—to see how resistance research breeds restoration research, and how all of it leads to better forests. Each of these trees (chestnut, elm and ash) have individual breeding and restoration stories, but by telling their stories together, we start to uncover a roadmap to follow for when the next invasive comes along.”

The first episode of “Backcross” released March 1. Each Tuesday, a new episode will release. You can listen and subscribe wherever you get your podcasts or on the station's website.