Historically in North America, American (or white) elm trees grew majestically along many of the streets of its cities and towns, up until the introduction of Dutch elm disease (DED) in the 1930s which ravaged and decimated over 95% of the population of this species. In recent years, researchers at the University of Guelph have discovered a mature, uninfected American elm tree on their campus, seemingly resistant to the fungal infection. With the goal to conserve the species from complete extinction, cloning the ‘survivor’ tree has become an important focus for researchers at the University of Guelph.
The American elm tree, Ulmus americana, is a deciduous tree native to North America, with a characteristic umbrella-shaped canopy and alternate and doubly-serrated leaves. DED, believed to originate from Asia and accidentally introduced to North America and Europe, is caused by a fungus from the Ascomycota family (scientific name Ophiostoma ulmi) and is spread by three species of bark beetles. Bark beetles enter and dig galleries underneath the bark, allowing the fungus to spread. DED affects elm trees through the sap-conducting tissues (phloem), cutting off the supply of sap to the tree and causing vascular wilt, most noticeable by the loss of green foliage in the canopy of trees (Natural Resources Canada, 2015). Though fungicide treatments have been developed, they can be costly and require repeated application that may only increase a tree’s lifespan by 5-10 years thus selection programs, such as at the University of Guelph, are important for distributing resistant trees (Tree Canada, n.d.).
Dr. Philip Gosling, one of the founding members of the Bruce Trail Conservancy (BTC) and an avid naturalist, and his wife, Susan Gosling, created the Gosling Research Institute for Plant Preservation (GRIPP) in 2012 with an emphasis on protecting and preserving American elm trees. Researchers developed a reliable plant cloning technique to clone 900 American elm trees using the ‘survivor’ tree. One of the scientists working on this project also mentioned that it may serve as a model to propagate other endangered plant species around the world (University of Guelph, 2012). To date, 100 trees have been donated to the BTC, most of which have been planted up in the Bruce Peninsula area.
On November 4th, 2021, the Biodiversity Team at BTC planted 10 of those cloned American elm trees on BTC property. The conservation of this endangered species is an important endeavor to maintain the biodiversity of flora and fauna in Ontario. American elm trees also produce fruit and flowers that are used as a food source by many bird species and squirrels as well as habitat for songbirds to nest, such as Baltimore orioles.
For more information on research by GRIPP, check out their website: https://gripp.ca/
by Shan Shukla, Vanessa Nhan, Monique Dosanjh (Recent Graduates from the Master of Forest Conservation program at the University of Toronto