what are these? are they beneficial or not?
We can't be sure from your photos, but we think the first one may be Pawlonia tree, which is a somewhat invasive alien with purple spring flowers with age. It has weak wood that dies back often. We'd suspect you have others nearby.
Your second photo we'd like to see in bloom.
The third one looks like it could be native sumac. If so, it would have brilliant fall color. The photo is not clear enough to know for sure.