Something Cut Off My Plants?

We planted a forsythia and a weeping willow this spring. 3 days ago the forsythia looked like someone had cut it. Today the willow, which was a small, 3-4ft, start and only 1/4in diameter, also looks cut off. The cuts were 45 degree angles and really look like somebody did this, but I hate to think my neighbors would do this. The cuttings were left behind and don't appear to be chewed. Any ideas?