Surviving Butternut Trees Benefit From Better Sites Rather than Disease Resistance
Groves of butternut trees were once a common feature along streams and in woodlots of the eastern United States. Native Americans, settlers, and farmers, as well as wildlife, have enjoyed butternuts, and butternut bark was used for medicine and as a dye. Healthy butternut trees are now rare because of a lethal new fungal disease called butternut canker. Geneticists with the Forest Service’s Northern Research Station Hardwood Tree Improvement and Regeneration Center at Purdue University have studied the rare healthy butternut trees growing among groups of trees dying from butternut canker. Their goal is to understand if the resistant butternut trees contain genes useful for breeding resistant butternut varieties. They focused on a stand of trees in southern Wisconsin, where a large group of butternut trees has been monitored for over 15 years. Using DNA from each tree and an extensive dataset related to tree health, they found that differences in survival among infected butternuts were not a matter of genetics but a matter of environment. The study revealed thatButternut survival is prolonged significantly when trees grow on drier sites. This finding suggests that butternut restoration work should now shift focus to finding genetic disease resistance in butternut relatives and proper site selection for reforestation.
Forest Service Partners