You buy a ferocious-looking guard dog - a cross between a rottweiler, a dobermann, a pit bull, and an alsation - and tie it to the tree to stop the boys getting near the apples. One night you hear sounds in the garden and wonder why the dog hasn't started barking. You go out, and see that the boys are there again, stealing your apples, and the dog is just looking on, wagging its tail. It makes no attempt to stop them at all.
The boys run off when they see you. You go to the dog and start shouting at it for being so useless, but then the dog turns nasty and begins growling and snarling at you. You back off, and the dog leaps for your throat. Your grisly death is only prevented by the rope tying the dog to the tree, which keeps you just out of the range of the dog's wicked-looking teeth.
The dog will not let you near it, so you have to call the vet to come and take it away. Your plan has failed dismally, and you have to try something else. Do you
Fit a burglar alarm to the tree