Maple tree: does it have canker?
I have an established Japanese Maple in my back garden and I noticed the main leader has either a fungus or possibly canker. I looked for photos of Japanese Maples with canker on the internet and it seems to resemble Nectria Canker for which there is no treatment. I was hoping to uplight the tree but since it seems diseased I wanted an expert's opinion as to whether or not the tree is salvageable? The diseased portion is about half way up the main leader and is about 10 in. length by 6 in. across. There is also another infected section on a smaller branch. Aside from this diseased area, the tree appears normal. It is located in a shady section with a canopy of Canadian Hemlocks and a large Tulip Poplar. The area under the tree is covered in a mix of English Ivy, Pachysandra and Vinca. Thank you for any assistance you can offer.
This is not a disease or a fungus.
It is damage from a boring beetle, which feeds on the cambium layer under the bark, disrupting the vascular system of the tree. There might be some woodpecker damage as well, as they can 'hear' and hunt the insects within.
There is no treatment, unfortunately. We'd recommend eventual removal.
Here is our page that helps homeowners decide when to remove a tree: