function turnAround()
	turtle.turnLeft()
	turtle.turnLeft()
end

function tryEatTreeInFront()
	turtle.select(3)
	if turtle.compare() then
		turtle.dig()
		turtle.forward()

		while turtle.detectUp() do
			turtle.digUp()
			turtle.up()
		end

		turtle.select(4)
		while not turtle.detectDown() do
			turtle.digDown()
			turtle.down()
		end
		return true
	else
		return false
	end
end

function plantTreeBelow()
	turtle.select(2)
	turtle.placeDown()
end

x = 3
y = 2

while true do
	--fuel turtle
	if turtle.getFuelLevel() == 0 then
		turtle.refuel(1)
	end

	--check sapling stock
	if turtle.getItemCount(2) == 0 then
		turtle.select(2)
		turnAround()
		turtle.suck(64)
		turnAround()
	end
	--get into position
	turtle.turnLeft()
	turtle.forward()
	turtle.turnRight()
	turtle.up()

	flag = true

	for i = 1, x do
		for j = 1, y + 1 do
			if tryEatTreeInFront() then
				turtle.up()
			else
				turtle.forward()
			end
			plantTreeBelow()
		end
		if flag then
			turtle.turnRight()
			turtle.forward()
			turtle.turnRight()
		else
			turtle.turnLeft()
			turtle.forward()
			turtle.turnLeft()
		end
		flag = not flag
	end

	turtle.forward()
	turtle.forward()
	turtle.forward()
	turtle.turnRight()
	turtle.forward()
	turtle.forward()
	turtle.turnRight()
	turtle.down()
	sleep(15)
end