With the cool, wet weather we've been having this Spring, tree diseases have been showing up more than usual this year. Pathogens like Anthracnose fungus thrive in this type of weather and tend to peter out when it gets warmer and drier, so their window to cause damage is a lot longer than usual.
For instance, Anthracnose might usually harm only a small portion of this London Plane tree, but this year it is almost entirely leafless, with small, stunted growth where there are leaves. You can also see witch's brooming, where the tree is pushing out new twigs around spots that were killed by the fungus.
- Ken Almstead, Arborist in Westchester and Riverdale