I've cut down (dead) trees. This is a job that could be done by one experienced person but I wouldn't tackle it on my own - it's an isolated area and if something goes wrong you are fucked. Trees are fuckin heavy and if one falls on you, you'll know about it. I don't know where the 16 year old would have got the experience to tackle this, the cuts look reasonably competent. It would also have taken a fairly long blade chainsaw, though it's hard to judge the thickness of the stump. Also, what a wanker.