Turtle Chopper

--pastebin get 02QNcL4m tree
--pastebin run 02QNcL4m

term.clear()
term.setCursorPos(1,1)
print("Hurde's Tree Program")
print("modded by LJack2k")
print("")
print("Press ENTER to stop")
print("")
print("First slot: The sapling")
print("Second slot: bonemeal")
print("Fourth slot: The wood type you want")
print("Fifth till sixteen: fuel")

function plant()
    turtle.select(1)
    if not turtle.compare() then
        turtle.place()
    end
end

function grow()
    turtle.select(4)
    if not turtle.compare() then
        turtle.select(2)
        turtle.place()
    end
end

function hak()
    while turtle.detectUp() do
        turtle.digUp()
        turtle.up()
    end
    while not turtle.detectDown() do
        turtle.down()
    end
    turtle.back()
end

function fuel()
  if turtle.getFuelLevel() < 100 then
   for i = 5, 16 do -- loop through the slots
    turtle.select(i) -- change to the slot
     if turtle.refuel(0) then -- if it's valid fuel
       local halfStack = math.ceil(turtle.getItemCount(i)/2) -- work out half of the amount of fuel in the slot
       turtle.refuel(halfStack) -- consume half the stack as fuel
     end
   end
  end
end

function program()
  while true do
    fuel()
    plant()
    turtle.select(4)
    if turtle.compare() then
     turtle.dig()
     turtle.forward()
     hak()
    else
     grow()
    end
    sleep(0.5)
  end
end

function exitProgram()
  repeat
    local ev, key = os.pullEvent('key')
  until key == keys.enter
end

parallel.waitForAny(program, exitProgram)