Farm

function failsafe()
  turtle.select(1)
  if not turtle.compareTo(14) then
    print("No more Saplings")
    print("Press any button to shutdown computer...")
    os.pullEvent("key")
    stop()
  end
  turtle.select(2)
  if not turtle.compareTo(15) then
    print("No more Bone Meal")
    print("Press any button to shutdown computer...")
    os.pullEvent("key")
    stop()
  end
  turtle.select(3)
  if not turtle.compareTo(16) then
    print("No more fuel")
    print("Press any button to shutdown computer...")
    os.pullEvent("key")
    stop()
  end
end
function stop()
  os.shutdown()
end
function chop() --Creates the function chop() for the wood chopping algorithm.
  turtle.dig()
  turtle.digUp()
  turtle.up()
end
Bonemealcount = 20 --Sets the number of times it will place bonemeal on the sapling. I don't recommend changing this as this ensures the trees will grow and don't worry, it won't use bonemeal when the tree is already grown.

while true do
  failsafe()
  while turtle.getFuelLevel() <= 20 do --Checks if a refuel is needed and if it is needed it will refuel.
    turtle.select(3)
    turtle.refuel(1)
  end
  turtle.select(1) --Selects and places sapling.
  turtle.place()
  turtle.select(2) --Selects bonemeal.
  for i = 1, Bonemealcount do --Places bonemeal on sapling.
    turtle.place()
  end
  while turtle.detect() do --Wood chopping algorithm.
    chop()
  end
  while not turtle.detectDown() do --Goes down until it reaches the ground.
    turtle.down()
  end
end