I was just up in shropshire doing some coppicing and took down some 15y old sycamore trees. I got about 3/4 of a mug full of sap out of each tree (from the felled tree rather that the root, the sap was already up) We all had a swig and no ill effects. Does anyone have any printed reference to this as to chemical composition or palletability? Is this a reliable thing to do with punters, and kids?