The historic sugar maple (Acer saccharum) in the Italianate Garden has become structurally unsafe due to the presence of a destructive wood-decay fungus.
Local tree experts confirmed the presence of Kretzschmaria deusta, commonly known as brittle cinder fungus. Hartney Greymont first identified signs of the fungus in December 2025, prompting further evaluation. A site-wide tree survey conducted by Bartlett Tree Experts in June 2026 found the tree to be at high risk of failure and recommended for emergency removal. The surrounding area has been fenced off and will remain closed until the work is complete.
How a Healthy-Looking Tree Can Become Unsafe
Kretzschmaria deusta commonly affects the roots and lower trunks of mature hardwood trees, including sugar maples. It breaks down the structural components of wood, causing infected tissue to lose strength and become brittle.
One of the challenges of the disease is that a tree’s crown and exterior may continue to appear relatively healthy even after significant internal decay has occurred. Its fungal fruiting bodies can also be small, dark and difficult to distinguish from the surrounding bark. As a result, the disease may not become evident until the tree’s structural integrity has already been seriously compromised.
There is no treatment that can eradicate the fungus once it has become established within a tree’s roots and heartwood. Professional inspection, diagnostic testing and careful risk assessment are therefore essential, particularly for mature trees growing in heavily used public spaces.
You can learn more about the disease through Bartlett Tree Expert's research on brittle cinder fungus.
What's Next?
MHS is working with professional arborists to plan the tree’s safe removal and thoughtfully consider the future of the site it has occupied for generations. Additional details will be shared within the next two to three weeks on this page.
The loss is a poignant reminder that the Garden’s mature and historic trees are living landmarks, requiring sustained expertise and investment to care for them, preserve them wherever possible, and establish a legacy for generations to come.
Photo credit: Angelina Rose Photography
