Fortunately, the dropped branches are few in number and small in diameter. In examining the breaks, they are suspicious looking. Certainly there was a weakness at the point of separation that caused them to break. Each fallen branch has a small cavity in the center and seemingly an exit hole on the side, as one might expect if an insect egg had been laid inside and hatched. It’s just a theory and I have not researched it, but it seems like a reasonable idea.
Besides, there’s nothing I can do about — except pick up the branches.