We have a large wood lot so when I through the same though process. As others have posted wood gasification is probably a better option. It was widely use in Europe in WWII.
Personally I have not pursued it. I'm waiting for someone to market a Stirling engine powered generator.
There is a pretty interesting book: "The Pegasus Unit - the lost art of driving without gasoline" by Niels A. Skov and Mark Papworth circa 1974