This is how my lovely bride helps me weed the garden. Can you say propane torch? Propane Torch ( photo / image / picture from eclecticgarden's Garden )
I have a much smaller version of that but with our drought I haven't been able to use it but once in the last 4-5 years.
I would worry about starting a fire where I wasn't suppose too. My father when he was alive, had a burning barrel and somehow he ended up burning the field next door. He was fined by the town and I am not sure if he had to pay for the firemen that came. I am just glad it didn't burn any houses in the neighborhood.
Hmmm... that reminds me ...I once knew an engineer who modified a lawnmower. Using only the deck(he removed everything else), he installed heating elements(as in a toaster) where the blades use to be. Powered by a long cord he would slowly move across his lawn setting the thatch on fire. The burn area was small, only under the smoking lawnmower deck but it was enough to rid the lawn of thatch. The result was a nice green lawn. Jerry