My tree has what appears to look like sawdust coming out of the base of the trunk. There is no other problem with the tree. It's about 20 ft tall and trimmed often.
Certified GKH Gardening Expert
My research show that your tree could be infested by the Giant Wood Moth.
A visible sign of this infestation is sawdust at the base of the tree.
Here is a link with more information.