Turtle Tree Farm

-- 2x2 Tree Farm By: ZakyyyHD
-- Save as "Fell." Capital "F" is required.
-- Protected under the Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported (http://creativecommons.org/licenses/by-nc-nd/3.0/)
--   Sapling chest to the LEFT of starting position.
--   Dump chest BEHIND starting position.
--   Bonemeal chest to the RIGHT of starting position.


-- Functions

-- Turn Around
function tAr()
 for t = 1, 2 do
  turtle.turnRight(t)
 end
end

-- Fell Vertically Up
function flUp()
 while turtle.detectUp() == true do
  cFuel()
  turtle.dig()
  turtle.digUp()
  turtle.up()
  height = height + 1
 end
end

-- Fell Vertically Down
function flDown()
 for x = 1, height do
  cFuel()
  turtle.digDown()
  turtle.down()
  turtle.dig()
 end
end

-- Refuel
function cFuel()
 if turtle.getFuelLevel() < 15 then
  turtle.select(1)
  turtle.refuel(2)
 end
end

-- Drop Items
function dropI()
 tAr()
  for i = 4, 16 do
   turtle.select(i)
   turtle.drop()
  end
 tAr()
end

-- Check Sapling
function cSapling()
 if turtle.getItemCount(2) < 16 then
  turtle.turnLeft()
  turtle.select(2)
  turtle.suck()
  turtle.select(1)
  turtle.turnRight()
 end
end

-- Grow Tree
function grow()
 turtle.select(3)
 turtle.place()
 turtle.select(1)
end

-- Check Bonemeal
function cBonemeal()
 if turtle.getItemCount(3) < 1 then
  turtle.turnRight()
  turtle.select(3)
  turtle.suck()
  turtle.select(1)
  turtle.turnLeft()
 end
end

-- Place Saplings
function replant()
 turtle.select(2)
 turtle.forward()
 turtle.forward()
 turtle.turnRight()
 sleep(.5)
 turtle.place()
 sleep(.5)
 turtle.turnLeft()
 turtle.back()
 sleep(.5)
 turtle.place()
 sleep(.5)
 turtle.turnRight()
 sleep(.5)
 turtle.place()
 sleep(.5)
 turtle.turnLeft()
 turtle.back()
 sleep(.5)
 turtle.place()
 sleep(.5)
end

-- Main loop
 while true do
  height = 0
  cFuel()
  cSapling()
  cBonemeal()
  replant()
  grow()
  turtle.dig()
  turtle.forward()
  flUp()
  turtle.dig()
  turtle.turnRight()
  turtle.dig()
  turtle.forward()
  turtle.turnLeft()
  turtle.dig()
  flDown()
  turtle.turnLeft()
  turtle.forward()
  turtle.turnRight()
  turtle.back()
  dropI()
 end

shell.run("Fell")