A lot of the time what happens is someone (friend, relative, nosy neighbor) notices flagging and surveying taking place and informs the landowner, but usually at that point cash has already been forked over and the perp is long gone. The initial timber cruise is usually hard to detect. A conscientious tree-hugging thief might even inform the timber buyer after the fact so the bogus lease will never be executed, knowing that if they're generally responsible human beings they only need to do their deed 3-4 times a decade anyway. Buyers likely have bonds/insurance coverage as well (odds of this increase if you hire a forester), so timber thieves can almost write it off as a victimless crime in their heads.
I've heard of some timber thieves leasing out plots of public land, but that doesn't sound like the best idea unless they're selling to a stupid craigslist hack for 1/10 of what they'd get elsewhere. A quick check of a property map and they'd be fucked.
I'm not sure what your area is like but taking scrap copper is a good way to make some extra cash. Depending on prices an old boiler can fetch £100 here of course you need to find abandoned buildings or at least make sure no one is home.
Where I live it is common to go get copper cable and burn off the rubber in a fire but theres loads of other metal. Just make sure the electric is off in the house, bring a hammer and start chasing the wires behind the walls. If you can get a few close mates you can knock a few houses over in a night.
I live in the middle of nowhere among farms, coal mines, and gas leases. There really aren't many abandoned buildings outside of the nearest town which has like 10% unemployment and has basically already been ransacked.
Potentially informative side note: Why am I not talking about leasing mineral rights as well?
1. More deed/courthouse work involved. More cameras.
2. Gas companies typically track down property owners, not visa versa.
