The bark on a neighbor's maple turned black and several branches of the tree died (Leaves were dry). I investigated because I have a maple tree about 15 feet from the distressed tree. The bark at the bottom of the distressed tree just fell off in my hands, and there were loads of earwigs. About half the bark around the tree's diameter from ground level to about 2 feet up is very loose and easily pulled off. There is a material like sawdust down on the ground, and underneath the loose bark the tree is very dry. Is it the mold or the earwigs causing the problem? And how do I prevent that problem from spreading to my nearby Maple?

The earwigs did not have anything to do with what you discovered other than under the bark with the humidity was a great place to be/hide. The saw dust is an indicator of boring insects. Boring insects typically show up as a secondary invader after something else has damaged the tree trunk. The loose bark being disconnected from the tree will be dry and would have fallen away eventually. The wood behind the bark is what we make lumber out of. Just from what you shared, unless you have similar damage to the trunks in your yard, this is not a disease that would spread.

I have the same problem with my 35 year old silver maple. I found earwigs under the bark. The tree is dying back in the limbs What iis my problem? I don’t want to lose this tree.