I like the idea of trail cameras, until you mentioned them I hadn't heard of them but googled them and they look good. We'll definitely go for that. We did resort to something similar with a couple of the persistent yachtsmen who thought it fun to anchor 200 ft off our jetty, get out their big binoculars and wolf whistle. I don't think they were looking at the Rhododendrons. We photographed them with a telephoto lens and put up a 'rogues gallery' on our notice board on the road, with a message 'Is this your pervy husband?'. We also sent it to the Yacht club and had a letter of apology.
As we don't really need logs for fuel, is there another safer way to process old wood without a chainsaw, where you chuck trees in and it minces them- I've seen tree surgeons with them but don't know what they are called or what they cost. Maybe there's one which will fit on a tractor? If it chopped them that would be even better.