Hello, We have 4 maples. Western Howard, on 3 acres in a residential area off main road. No construction, good drainage, clayish soil. I don't use fertilizer or pesticides. Trees are 20 years old. One tree is very stressed. It has been for 5-10 years. Its in the back yard, sunny southern open are. Last 2-3 years we noticed bore holes. Other 3 trees are in front yard, along drive, still sunny area. These have been healthy but this year we noticed bore holes. Appreciate any help you can provide. First two pictures are of first tree, 3rd photo is roots of one of the healthy trees.
The large holes in the first and second photos appear to be sapsucker feeding holes. The holes in a row are especially typical of the probings of this bird. http://extension.umd.edu/hgic/woodpeckers-and-sapsuckers It does not harm the tree, so the tree must be declining from other problems.
The third photo shows a major problem with girdling roots. Girdling roots eventually create a tourniquet around the tree and choke it to death. Here is info on his problem: http://extension.umd.edu/hgic/girdling-roots-trees-and-shrubs
Some maples are particularly prone to girdling roots, such as the Norway maple. Unfortunately, a severe situation cannot be remedied.