Fir Wood Tree Farm (Troy Cheek)

-- Tree Farm Tending Turtle
-- Cuts down and replants fir trees
-- Variables
turtle.select(1)
local tArgs = { ... }
local togo = tonumber(tArgs[1])
togo = togo or 1
local sapling = 0
term.clear()
term.setCursorPos(1,1)
print(os.getComputerLabel() .. " at your service!")
print()
print("Please place blocks as follows:")
print("Slot 1 - Fuel (coal, lava, wood)")
print("Slot 2 - Saplings (Fir is best)")
print()
print("Place turtle over chest at edge of farm.")
print()
print("Press [ENTER] when ready.")
read(input)

-- Starting Out
if turtle.getItemCount(1) < 1 then
  print("No fuel! Abort!")
  os.quit()
end
sapling = 0
if turtle.getItemCount(2) > 0 then
  sapling = 1
end

-- Functions
local function tfuel(amount)
 if turtle.getFuelLevel() < 16 then
  turtle.select(1)
  turtle.refuel(amount)
 end
end

local function tforward(steps) -- turtle takes x steps forward
  if steps==nil or steps==0 then steps=1 end
  tfuel(1)
  for i=1,steps do
    while not turtle.forward() do
      turtle.dig()
      turtle.attack()
    end
  end
end

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

local function discard() -- drop off extra stuff into water
  if turtle.getItemCount(3)<1 then
    return
  end
  while not turtle.down() do
    turtle.digDown()
  end
  for i = 3,16 do
    if turtle.getItemCount(i)>0 then
      turtle.select(i)
      turtle.dropDown()
    end
  end
  while not turtle.up() do
    turtle.digUp()
  end
  turtle.select(1)
end

local function climb()
  if turtle.detect() then
    turtle.dig()
    tforward()
    local cnt=0
    repeat
      cnt = cnt + 1
      turtle.dig()
      sleep(0.5)
      turtle.digUp()
      tfuel(1)
      turtle.up()
    until not turtle.detect()
    turtle.turnRight()
    tforward()
    turtle.turnLeft()
    for i = 1,cnt do
      turtle.digDown()
      sleep(0.5)
      tfuel(1)
      turtle.down()
      turtle.dig()
    end
    turtle.digDown()
    turtle.select(2)
    turtle.placeDown()
    tforward()
    turtle.digDown()
    turtle.select(2)
    turtle.placeDown()
    turtle.turnLeft()
    tforward()
    turtle.digDown()
    turtle.select(2)
    turtle.placeDown()
    turtle.turnLeft()
    tforward()
    turtle.digDown()
    turtle.select(2)
    turtle.placeDown()
    turnaround()
    tforward(2)
  else
    tforward(3)
  end
  discard()
end

-- Main Loop
tforward(2)  -- move into first position
for r = 1,4 do
  for i = 1,4 do
    climb() -- climb and cut tree
    if i<4 then
      tforward(2)
    end
  end
  if r<4 then
    if r%2>0 then
      turtle.turnRight()
    else
      turtle.turnLeft()
    end
    tforward(4+2*(r%2))
    if r%2>0 then
      turtle.turnRight()
    else
      turtle.turnLeft()
    end
  end
end
turtle.turnRight()
tforward(16)  -- move back to base
turtle.turnLeft()
tforward(2)
turnaround()
turtle.select(2)  -- reload saplings
turtle.suckDown()
turtle.select(3)
turtle.dropDown()
turtle.select(1)