This is a link to a short piece (four minutes) from Radio 4's 'Today' program, which reports that...
"Nervous parents are making the countryside "out of bounds" for their children, a survey has suggested. Reporter Sanchia Berg visits one primary school to speak to children about their experience of the countryside. Tom Hodgkinson, editor of magazine The Idler, discusses if the idea of play is being taken out of childhood."
One child wouldn't want to climb trees "in case he was poisoned".