Fixed Advanced Felling Turtle

-- Advanced 2x2 Tree Felling Program
-- Written by ianJustice
-- Inspired by SethBling
-- Tree detection fixed by ArbitraryHubris

-- Place in front of left side of 2x2 tree

fuel = 1
saplings = 2
bonemeal = 3
logs = 4

-- Place fuel in indicated slot

local function checkFuel()
  if turtle.getFuelLevel() < 1 then
    turtle.select(fuel)
    turtle.refuel(1)
  end
end

local function digAndMove()
  turtle.dig()
  turtle.attack()
  checkFuel()
  turtle.forward()
end

local function digAndMoveUp()
  turtle.digUp()
  checkFuel()
  turtle.up()
end

local function turnAround()
  turtle.turnRight()
  turtle.turnRight()
end

local function chopUp()
  digAndMove()
  while turtle.digUp() do
    turtle.dig()
    checkFuel()
    turtle.up()
  end

  turtle.dig()
  checkFuel()

  while turtle.down() do
    checkFuel()
  end
end

local function fell()
  chopUp()
  turnAround()
  digAndMove()
  turtle.turnLeft()
  digAndMove()
  turtle.turnLeft()
  chopUp()
  turtle.turnLeft()
  digAndMove()
  turtle.turnLeft()
  digAndMove()
  turnAround()
end

local function plant()
  digAndMove()
  digAndMove()
  turtle.turnRight()
  turtle.select(saplings)
  turtle.place()
  turtle.turnRight()
  digAndMove()
  turtle.turnLeft()
  turtle.place()
  turtle.turnLeft()
  turtle.place()
  turnAround()
  digAndMove()
  turnAround()
  turtle.place()
  turtle.select(bonemeal)
  turtle.place()
  turtle.select(saplings)
  seconds = 0
  while turtle.compare() do
    if seconds == 300 then
      turtle.select(bonemeal)
      turtle.place()
      turtle.select(saplings)
      seconds = 0
    end
    seconds = seconds + 1
    os.sleep(1.0)
  end
end

local function dropLogs()
  print("Depositing Lumber")
  for i = 5, 16 do
    turtle.select(i)
    if turtle.compareTo(logs) == true then
      turtle.drop()
    end
  end
end

local function getCoal()
  if turtle.getItemCount(fuel) < 4 then
    print("Resupplying Coal")
    turtle.select(fuel)
    turtle.suck(16)
  end
end

local function getSaplings()
  if turtle.getItemCount(saplings) < 4 then
    print("Resupplying Saplings")
    turtle.select(saplings)
    turtle.suckDown(16)
  end
end

local function getBonemeal()
  if turtle.getItemCount(bonemeal) < 4 then
    print("Resupplying Bonemeal")
    turtle.select(bonemeal)
    turtle.suckUp(16)
  end
end

while true do
  plant()
  print("Tree successfully planted")
  fell()
  print("Tree successfully felled")
  turtle.turnLeft()
  getCoal()
  turtle.turnLeft()
  dropLogs()
  turnAround()
  getSaplings()
  getBonemeal()
end