Laws of this type do not accomplish what they were intended to do.  The intent as I understand it is to create an area that will be free of firearms and therefore safe.  But for people who don’t obey these laws will do as they please.  For them, you have created is an environment that is easy picking.  If they wanted to do something wrong, what is there that can stop them?  Do we rely on the police?  By that time the mayhem is over.   All the police will be able to do is to write the crime report.  By allowing concealed carry, you have modified the environment increasing the unknown.  Now you don’t know who will be able to defend themselves.  And for the person who wants to do bodily harm and doesn’t care if they die, no law is going to stop them.   Hopefully their level of destruction may be reduced.  The only way a law like this can work is that you setup walls in which there are metal detectors at all of the entrances. 
With that said, I am in favor of concealed carry in Va state forests.