You'll need a license to cut trees down and insurance. Once you have that, you have to find the trees to cut down. Thats the hard part. Best place to start is with excavation contractors to see if they can contract you to clear building lots. You could poach it but if you get caught, you'll most likely lose your license. My neighbor has a huge tree in his back yard he wants taken down in the next year or so. I'm going to see if a friend will cut it down for the wood. It's about 6-8 cords maybe more.