Woodcutting turtle

local refuel = 0
term.clear()
term.setCursorPos(1,1)
print("I had to refuel "..refuel.." times!")
turtle.select(1)
turtle.dig()
turtle.forward()
function CheckFuel()
  if turtle.getFuelLevel() <= 5 then
    turtle.select(16)
    refuel = refuel + 1
    term.clear()
    term.setCursorPos(1,1)
    print("I had to refuel "..refuel.."times!")
    turtle.refuel(1)
    turtle.select(1)
  end
end


while turtle.compareUp() do
  CheckFuel()
  turtle.digUp()
  turtle.up()
end

while turtle.detectDown() == false do
  CheckFuel()
  turtle.down()
end