There are few rules in foraging, but I’ve gathered a few from years experience and other foragers.
1. Know what you gather. If you do not have a mentor/teacher, get a good trail guide to wild edibles. The wrong plant can make you very ill and some can kill you.
2. Never gather endangered species.
3. Do not break laws to gather/forage. This is, do not trespass on private property and do not gather in protected areas.
4. Don’t be greedy. Gather only what you need and leave a little for next time.