turtle autotreefarm w/ startup

-- Setup at http://imgur.com/a/dTqGO
--once setup this tree farm will refuel itself
--and reorient itself on startup without need of interaction.
--based off of itsmartin's treefarm program http://youtu.be/nJYxL_sg96U


function goHome()
    turtle.select(13)
    if not turtle.compareDown() then
        turtle.select(14)
            while not turtle.compareUp() do
                turtle.digUp()
                turtle.up()
            end
            while not turtle.detectDown() do
                turtle.down()
            end
            fuel()
            moveFarmDeposit()
        else

    end
end

function fuel()
    while turtle.getFuelLevel() <= 30 do
        if turtle.getItemCount(1) == 0 then
            print("Help, I'm out of fuel")
            turtle.turnLeft()
            turtle.turnLeft()
            turtle.turnLeft()
            turtle.turnLeft()
            os.sleep(.5)
            else
            turtle.select(1)
            turtle.refuel(1)
            end
    end
end

function plantSapling()
    turtle.select(16)
    turtle.place()
end

function waitForSaplings()
    turtle.select(16)
    while turtle.getItemCount(16) < 2 do
        os.sleep(.5)
        turtle.suckDown()
    end
end

function waitForTree()
    turtle.select(15)
    while not turtle.compare() do
        os.sleep(.5)
    end
end

function cutTree()
    turtle.select(1)
    turtle.dig()
    turtle.forward()
    os.sleep(.5)
    local count = 1
    while turtle.compareUp() do
        turtle.digUp()
        turtle.up()
        count = count + 1
    end
    for i=1,count do
        turtle.down()
    end
end

function moveFarmDeposit()
    for x=1,12 do
        turtle.select(x)
        turtle.drop()
        end
    turtle.back()
end

goHome()

if turtle.getItemCount(13) == 0 or turtle.getItemCount(14) == 0 or turtle.getItemCount(15) == 0 then
print("place 1 wood in slot 1")
print("place 1 chest in slot 13")
print("place 1 cobblestone in slot 14")
print("place 1 piece of wood from the tree you're growing in slot 15")
print("place your saplings in slot 16")
return
end

while true do
    waitForSaplings()
    plantSapling()
    waitForTree()
    cutTree()
    fuel()
    moveFarmDeposit()
end