As the article mentions but doesn't emphasise the problem is not so much individuals picking mushrooms to eat themselves but "commercial fungi foraging" by people picking them to sell to shops and restaurants. So, another example of the "tragedy of the commons under capitalism".Incidentally, the regulations for Richmond Park say you can't pick mushrooms (or flowers) without the permission of the Secretary of State, so I wrote asking for permission but, in a letter dated 1 April, was refused.