The National Capital Commission has begun to take down more than two dozen diseased trees near Confederation Boulevard.
Dutch elm disease has claimed 14 trees.
10 other trees including four Maples are dying from 'urban and environmental stress'.
Maintenance crews started chopping trees down today on a number of streets including Elgin, Laurier Avenue and Sussex Drive.
It will take crews most of October to complete the tree removal.
The tree cutting is necessary for the safety of pedestrians and motorists.