Steve's Carts tree farm. Most expensive item: 5 diamonds.
You'll need as components for the cart:
- Standard Hull
- Coal Engine
- Woodcutter
- Side Chests
Then build a Cart Assembler. Put the components mentioned up to into the left, click on assemble on the bottom right, add a stack of charcoal and 15 minutes later or so you'll have a shiny new cart.
Meanwhile build a bunch of tracks, one Advanced Detector Rail and one Cargo Manager.
Set the tracks up in the shape of an E: (the red wool is only for your counting convinience, don't place it on live)
View attachment 1777
Place the Cargo Manager on the long side of the E (like in the picture above) directly next to the ADRail. Remember the color of the side, that touches your Advanced Detector Rail. Open the Cargo Manager and configure it like in the following picture (I had red as my track facing side):
View attachment 1778
When the cart is ready, place it, fill it with saplings and a stack of logs and watch the cart work. It will refuel itself via the logs it produces. For greater efficiency you can add some external ways to autocraft some logs into charcoal and let your cart run on that.
Wiki for Steve's Carts:
http://stevescarts2.wikispaces.com/