redwood

function needFuel()
  if turtle.getFuelLevel() <= 230 then
    turtle.select(2)
    turtle.refuel(1)
  end
end

function digTop()
  while turtle.detect() do
    turtle.digUp()
    turtle.dig()
    turtle.up()
    needFuel()
  end
  while not turtle.detectDown() do
    turtle.down()
  end
  turtle.forward()
end

function nextLeft()
  turtle.forward()
  turtle.forward()
  turtle.turnLeft()
  turtle.dig()
  turtle.forward()
  turtle.turnLeft()
  turtle.forward()
  turtle.forward()
  turtle.forward()
  end

function nextRight()
  turtle.forward()
  turtle.forward()
  turtle.turnRight()
  turtle.dig()
  turtle.forward()
  turtle.turnRight()
  turtle.forward()
  turtle.forward()
  turtle.forward()
end

function mailHome()
  if turtle.getItemCount(3) ~= 0 then
  turtle.dig()
  turtle.select(1)
  turtle.place()
  end
  for i = 3,16 do
    turtle.select(i)
    turtle.drop()
  end
  turtle.select(1)
  turtle.dig()
end

function upBack()
  while turtle.detect() do
    digTop()
  end
  mailHome()
  nextLeft()
  while turtle.detect() do
    digTop()
  end
  mailHome()
  nextRight()
end

local tree = ""
  print("Lets cut down some trees!")
  print("Slot 1 - Ender Chest")
  print("Slot 2 - Fuel")

  write("Tree width? ")
  tree = read()
  loops = (tree+1)/2
  print("Okay, tree width is"..tree)
  print("Times I will loop: "..loops)
  print("This tree is coming down, you may want to back up...")
    for i2 = 1,loops do
        upBack()
    end