Large Tree Farm

--[[
TreeFarmer

by Severino

Version 4.1.1

  This program will plant a grove of trees, fertilizing as it goes, then will return to each tree and harvest it if it has grown and collect the saplings. The saplings and anything else dropped by the harvested trees will be collected. The saplings collected will be used to replant and extra will placed in the chest containing the sapling. Everything else that is collected will be placed in an inventory chest.

  If the turtle runs into something not expected, it will report that it was blocked then destroy it. If the supply of fuel in the turtle drops to 1 then it reports that it is out of fuel and wait to be refueled. If the supply of saplings drops to 1 it will contintreeue to harvest trees and collect more saplings. It will never use the last sapling so it has something to compare with.

  You can start the tree farm with two or more saplings or a single sapling and an existing tree. It will harvest the trees that it finds and collect saplings, and then continue to use those saplings to populate the tree farm.

  At the end of each transit through the tree farm the excess saplings will be placed in the sapling chest.  If the sapling chest becomes full, it will report that problem and wait for the chest to be emptied.  It will also deposit any wood and other items collected from harvesting and place them in the inventory chest.  If this chest becomes full it will report the problem and wait for it to be emptied.  If it runs out of bonemeal it will continue to plant and harvest but the trees will not be harvested until they have grown.

  Added the ability to automatically restart even stopped in the middle of harvesting.  This is accomplished by placing a railing around the logging area, and placing a chest and railing in the turtle to he can determine the borders and the starting position.

  Added furnaces so that if the turtle runs out of fuel, or if the inventory chest becomes full, the he can make charcoal, until the fuel chest becomes full.

  Now doesn't use a set number of rows and column.  Trees will be planted in all space available between the fences.

Materials Required:
  1 mining or felling turtle
  4 chests
  a sapling for each tree location (numberOfRows * treesPerRow)
  1 log same type as the sapling
  fuel (suggest coal or coalcoke)
  1 railing (used to identify borders of grove on startup.)
  1 chest (used to identify starting position and orientation.)
  bone meal (optional)

Setup:
  Diagram:
      +-F-F-F----------------------------...-------------------------------------+
      |                                                                          |
      :                                                                          :
      |                                                                          |
      |s                                                                         |
      |a                                                                         |
      |p                                                                         |
  [inv]X                                                                         |
      |b                                                                         |
      |o                                                                         |
      |n                                                                         |
      |                                                                          |
      :                                                                          :
      |                                                                          |
      +------------------------------------...-----------------------------------+
  [inv] = Inventory Chest
   sap  = Sapling Chest
   bon  = Bone meal Chest
    X   = Fuel Chest below turtle will charcoal
  + - | = Fencing or Gates around area for grove of trees, any size.
    F   = Furnace (0 or more, above the fence with 1 empty space between the fence and the furnace, and 1 empty space between each furnace)

  There are variables in the beginning of the program that set the number of trees that will be in each row and the number of rows to plant, as well as the space between the trees. These should be modified to suit your preferences.

  Place turtle over a chest in a level dirt field facing away. Place a chest to the left, right and behind the turtle. These can be single or double chests.

  Place fuel in the chest under the turtle. Place saplings in the chest to the left. Place bone meal in the chest to the right. The chest behind the turtle starts out empty and will be filled with the wood that is harvested and anything else dropped by the harvested trees.

  Put a fence around the level area that will contain the trees with the sapling and bone meal chest inside of the fence one block.

  Put fuel in slot 1, fertilizer in slot 2, a chest in slot 3, a fence in slot 4, a gate in slot 5, saplings in slot 6, and a block of wood of the same type that is to be harvested in slot 7.


Setup
  Slot 1 = Fuel (charcoal)
  Slot 2 = Fertilizer
  Slot 3 = Chest
  Slot 4 = Fence
  Slot 5 = Gate
  Slot 6 = Saplings
  Slot 7 = Wood same type as sapling
]]--

version = "4.1.1"
treesPerRow = 6
numberOfRows = 4
spaceBetweenTrees = 4
plantTrees = true -- Set to false to clear tree grove.
harvestWide = false -- True means to harvest everything on each level of a tree, including leaves
slotFuel = 1
slotBonemeal = 2
slotChest = 3
slotFence = 4
slotGate = 5
slotSapling = 6
-- You can use the wood it harvests as fuel if you want.  If so then use slotWood = slotFuel
slotWood = 7
logfile = nil

abortCircuit = false
minerID = os.getComputerID()
consoleID = 0
furnaceCount = nil

function checkSetup()
  updateStatus("Checking Setup")
  if turtle.getItemCount(slotFuel) < 2 then
    updateStatus("2+ Fuel needed in slot "..slotFuel)
    while turtle.getItemCount(slotFuel) < 2 do
      sleep(2)
    end
  else
    updateStatus(turtle.getItemCount(slotFuel).." fueld present in slot "..slotFuel)
  end
  if turtle.getItemCount(slotBonemeal) < 1 then
    updateStatus("Fertilizer recommended in slot "..slotBonemeal)
  else
    updateStatus("Fertilizer present in slot "..slotBonemeal)
  end
  if turtle.getItemCount(slotChest) < 1 then
    updateStatus("Chest needed in slot "..slotChest)
    while turtle.getItemCount(slotChest) < 1 do
      sleep(2)
    end
  else
    updateStatus("Chest present in slot "..slotChest)
  end
  if turtle.getItemCount(slotFence) < 1 then
    updateStatus("Fence needed in slot "..slotFence)
    while turtle.getItemCount(slotFence) < 1 do
      sleep(2)
    end
  else
    updateStatus("Fence present in slot "..slotFence)
  end
  if turtle.getItemCount(slotGate) < 1 then
    updateStatus("Gate may be needed in slot "..slotGate)
  else
    updateStatus("Gate present in slot "..slotGate)
  end
  if turtle.getItemCount(slotSapling) < 1 then
    updateStatus("Saplings needed in slot "..slotSapling)
    while turtle.getItemCount(slotSapling) < treesPerRow * numberOfRows do
      sleep(2)
    end
  else
    updateStatus(turtle.getItemCount(slotSapling) .. " Saplings present in slot "..slotSapling)
  end
  if turtle.getItemCount(slotWood) < 1 then
    updateStatus("Wood needed in slot "..slotWood)
    while turtle.getItemCount(slotWood) < 1 do
      sleep(2)
    end
  else
    updateStatus("Wood present in slot "..slotWood)
  end
end
function updateStatus(msg, silent)
  if not rednet.isOpen("right") then rednet.open("right") end
  if rednet.isOpen("right") then
    networkmsg = "Miner ".. minerID..": "..msg
    if consoleID == 0 then
      rednet.broadcast(networkmsg)
    else
      rednet.send(consoleID,networkmsg)
    end
  end
  if not silent then print(msg) end
  updateLog(msg)
end
function getConsoleID()
  local fname = "ConsoleID"
  if fs.exists(fname) then
    file = fs.open(fname, "r")
    consoleID = tonumber(file.readAll())
    file.close()
    print("Monitor Console ID: "..consoleID)
  else
    updateStatus("Waiting for Console ID...",true)
    term.write("Monitor Console ID: ")
    consoleID = io.read()
    file = fs.open(fname, "w")
    file.write(consoleID)
    file.close()
    consoleID = tonumber(consoleID)
  end
end
function updateLog(msg)
  local fname = 'log'
  if fs.exists(fname) then
    logfile = fs.open(fname, "a")
  else
    logfile = fs.open(fname, "w")
  end
  updateTime = textutils.formatTime(os.time())
  logfile.write(updateTime.." "..msg.."\n")
  logfile.close()
end
function selectSapling()
  -- Look at all of the slots and if a slot other than the default sapling slot contains saplings, then return this slot.
  local slot = 0
  for slot=1,16 do
    if slot ~= slotSapling then
      if turtle.getItemCount(slot) > 1 then
        turtle.select(slot)
        if turtle.compareTo(slotSapling) then return true end
      end
    end
  end
  if turtle.getItemCount(slotSapling) > 1 then
    turtle.select(slotSapling)
    return true
  end
  return false
end
function selectWood()
  local slot = 0
  for slot = slotWood + 1,16 do
    turtle.select(slot)
    if turtle.compareTo(slotWood) then return true end
  end
  return false
end
function selectBonemeal()
  -- Look at all of the slots and if a slot other than the default bone meal slot contains bone meal, then move them into the default bone meal slot.
  local slot = 0
  for slot=1,16 do
    if slot ~= slotBonemeal then
      if turtle.getItemCount(slot) > 1 then
        turtle.select(slot)
        if turtle.compareTo(slotBonemeal) then return true end
      end
    end
  end
  if turtle.getItemCount(slotBonemeal) > 1 then
    turtle.select(slotBonemeal)
    return true
  end
  return false
end
function plantSapling()
  -- Plant a sapling report if there is a problem.
  if plantTrees then
    if selectSapling() then
      if turtle.place() then
        return true
      else
        updateStatus("Unable to plant sapling.")
        return false
      end
    else
      updateStatus("Out of saplings.")
      return false
    end
  else
    return false
  end
end
function applyBonemeal()
  -- Apply fertilizer and report if there is a problem.
  if selectBonemeal() then
    local cnt = 0
    local applied = false
    while isSapling() and cnt < 10 do
      if selectBonemeal() then
        if turtle.place() then applied = true end
        cnt = cnt + 1
      end
    end
    if applied then
      return true
    else
      updateStatus("Unable to fertilize.")
      return false
    end
  else
    updateStatus("Out of fertilizer.")
    return false
  end
end
function refuel()
  -- Refuel from the slot specified if needed
  turtle.select(slotFuel)
  -- Check to see if any other slot has the same material
  local s = 0
  for s=1,16,1 do
    if s ~= slotFuel and s ~= slotWood then
      if turtle.compareTo(s) then
        turtle.select(s)
        turtle.transferTo(slotFuel)
      end
    end
  end
  -- Make sure there is enough fuel to harvest every tree and the distance between
  while turtle.getFuelLevel() <= (treesPerRow * numberOfRows) * 10 * 2
      + (treesPerRow * numberOfRows * spaceBetweenTrees)
      + (spaceBetweenTrees * 2) do
    turtle.select(slotFuel)
    if turtle.getItemCount(slotFuel) <= 1 then
      updateStatus("Out of fuel.")
      return false
    end
    local q = turtle.getItemCount(slotFuel) - 1
    if q > 5 then q = 5 else updateStatus("Low on fuel.") end
    turtle.refuel(q)
    updateStatus("Refueled to level: "..turtle.getFuelLevel())
  end
  turtle.select(slotWood)
  if turtle.getFuelLevel() < treesPerRow * numberOfRows * spaceBetweenTrees then
    abortCircuit = true
    return false
  else
    return true
  end

end
function moveForward()
  turtle.suck()
  if not turtle.forward() then
    updateStatus("Path blocked.")
    if turtle.detect() then
      -- Something is there so try destroy it!!!
      turtle.dig()
    end
    while not turtle.forward() do
      sleep(2)
    end
  end
end
function moveBack()
  turtle.suck()
  if not turtle.back() then
    updateStatus("Path blocked.")
    while not turtle.back() do
      sleep(2)
    end
  end
end
function goForward()
  turtle.suck()
  return turtle.forward()
end
function gatherSaplings()
  -- Should be facing sapling or where tree was.  Move around the tree collecting anything that has dropped.
  turtle.select(slotWood)
  refuel()
  turtle.suck()
  turtle.turnLeft()
  moveForward()
  turtle.suck()
  turtle.turnRight()
  moveForward()
  turtle.suck()
  turtle.turnLeft()
  turtle.suck()
  turtle.turnRight()
  moveForward()
  turtle.suck()
  turtle.turnLeft()
  turtle.suck()
  turtle.turnRight()
  turtle.turnRight()
  moveForward()
  turtle.suck()
  turtle.turnLeft()
  turtle.suck()
  turtle.turnRight()
  moveForward()
  turtle.suck()
  turtle.turnLeft()
  turtle.suck()
  turtle.turnRight()
  turtle.turnRight()
  moveForward()
  turtle.suck()
  turtle.turnLeft()
  turtle.suck()
  turtle.turnRight()
  moveForward()
  turtle.suck()
  turtle.turnRight()
  turtle.suck()
  turtle.turnRight()
  turtle.suck()
end
function isWood()
  turtle.select(slotWood)
  local woodFound = turtle.compare()
  return woodFound
end
function isWoodUp()
  turtle.select(slotWood)
  local woodFound = turtle.compareUp()
  return woodFound
end
function isSapling()
  local saplingFound = false
  turtle.select(slotSapling)
  saplingFound = turtle.compare()
  if not saplingFound then print("Not a sapling.") end
  return saplingFound
end
function harvestLevel()
  -- Don't go too far so limit expansion to half the distance between the trees.
  local found = false
  for d=1,4 do
    if not refuel() then return false end
    local c = 0
    while turtle.detect() and c < spaceBetweenTrees-2 do
      c = c + 1
      found = true
      turtle.dig()
      turtle.forward()
      turtle.turnLeft()
      if turtle.detect() then
        turtle.dig()
        turtle.forward()
        turtle.dig()
        turtle.turnLeft()
        turtle.dig()
        turtle.turnLeft()
        turtle.turnLeft()
        turtle.dig()
        turtle.turnLeft()
        turtle.back()
      end
      turtle.turnLeft()
      turtle.turnLeft()
      if turtle.detect() then
        turtle.dig()
        turtle.forward()
        turtle.dig()
        turtle.turnLeft()
        turtle.dig()
        turtle.turnLeft()
        turtle.turnLeft()
        turtle.dig()
        turtle.turnLeft()
        turtle.back()
      end
      turtle.turnLeft()
    end
    for a=1,c do turtle.back() end
    turtle.turnLeft()
  end
  return found
end
function harvestWood()
  if isWood() then
    turtle.dig()
    return true
  else
    return false
  end
end
function harvestTrunk()
  -- Go up the trunk and clear each level spreading out up to half the distance between the trees.
  turtle.select(slotWood)
  if turtle.detect() then
    turtle.dig()
    turtle.forward()
    turtle.suck()
    local h = 0
    if harvestWide then
      while harvestLevel() or isWoodUp() do
        turtle.digUp()
        if turtle.up() then h = h + 1 end
      end
    else
      while isWoodUp() do
        turtle.digUp()
        if turtle.up() then h = h + 1 else break end
      end
    end
    local d  = 1
    refuel()
    while d <= h do
      if turtle.detectDown() then
        turtle.digDown()
      end
      if turtle.down() then
        d = d + 1
      end
    end
    turtle.suck()
    turtle.back()
  end
end
function saplingsAvailable()
  local saplingCount = 0
  for slot=1,16 do
    if slot == slotSapling then
      saplingCount = saplingCount + turtle.getItemCount(slot)
    else
      turtle.select(slot)
      if turtle.compareTo(slotSapling) then
        saplingCount = saplingCount + turtle.getItemCount(slot)
      end
    end
  end
  return saplingCount
end
function facingAChest()
  turtle.select(slotChest)
  return turtle.compare()
end
function aboveAChest()
  turtle.select(slotChest)
  return turtle.compareDown()
end
function facingAFence()
  turtle.select(slotFence)
  if turtle.compare() then return true end
  turtle.select(slotGate)
  return turtle.compare()
end
function aboveAFence()
  turtle.select(slotFence)
  if turtle.compareDown() then return true end
  turtle.select(slotGate)
  return turtle.compareDown()
end
function serviceFurnaces()
  -- Load up on wood first.
  turtle.turnRight()
  turtle.turnRight()
  turtle.select(slotWood+1)
  while turtle.suck() do
    -- Keep taking wood until full.
  end
  -- Now unload the top 2 slots to get fuel
  for slot=15,16 do
    turtle.select(slot)
    if turtle.compareTo(slotWood) then turtle.drop() end
  end
  turtle.turnRight()
  turtle.turnRight()
  updateStatus("Checking furnaces")
  local distanceToFence = 0
  moveForward()
  turtle.turnLeft()
  while not facingAFence() do
    moveForward()
    distanceToFence = distanceToFence + 1
  end
  turtle.up()
  moveForward()
  -- Should now be above the fence below the furnace.
  if furnaceCount == nil then
    if turtle.detectUp() then furnaceCount = 1 else furnaceCount = 0 end
  end
  furnaceIdx = 1
  anotherFurnace = true
  while turtle.detectUp() and anotherFurnace do
    updateStatus("Loading furnace "..furnaceIdx)
    while selectWood() and turtle.dropUp() do
      -- Keep adding wood to furnace as fuel until out of wood or furnace is full.
    end
    -- Now move to the top to add material to smelt
    if turtle.back() then
      if turtle.up() then
        if turtle.up() then
          if turtle.forward() then
            if turtle.detectDown() then
              while selectWood() and turtle.dropDown() do
                -- Keep adding wood to furnace to smelt until out of wood or furnace is full.
              end
              -- Now move to the right of the furnace to remove fuel
              turtle.turnLeft()
              if turtle.back() then
                if turtle.down() then
                  updateStatus("Unloading furnace "..furnaceIdx)
                  turtle.select(slotFuel)
                  while turtle.suck() do
                    -- Remove all fuel in furnace
                  end
                  turtle.turnRight()
                  turtle.turnRight()
                  if not turtle.detect() then anotherFurnace = false end
                  turtle.turnLeft()
                  turtle.turnLeft()
                  turtle.up()
                end
                turtle.forward()
              end
              turtle.turnRight()
            end
            moveBack()
          end
          turtle.down()
        end
        turtle.down()
      end
      turtle.forward()
    end
    -- Now go to the next furnace if there is wood available
    if selectWood() and anotherFurnace then
      turtle.turnRight()
      if turtle.forward() then
        if turtle.forward() then
          furnaceIdx = furnaceIdx + 1
          if turtle.detectUp() then furnaceCount = furnaceCount + 1 end
        end
      end
      turtle.turnLeft()
    end
  end
  -- Now return the first furnace
  if furnaceIdx > 1 then
    turtle.turnLeft()
    for bi = 1,furnaceIdx-1 do
      turtle.forward()
      turtle.forward()
    end
    turtle.turnRight()
  end
  -- Now return to start and unload extra wood and fuel
  updateStatus("Returning to start.")
  turtle.turnLeft()
  turtle.turnLeft()
  moveForward()
  if not turtle.down() then
    turtle.digDown()
    while not turtle.down() do
      updateStatus("Down blocked.")
      sleep(10)
    end
  end
  for di = 1,distanceToFence do moveForward() end
  turtle.turnRight()
  moveForward()
  -- Should be back at the start. - make sure.
  turtle.select(slotChest)
  if not turtle.compareDown() then
    -- Lost so find home.
    updateStatus("Lost. Returning to start.")
    locateStartingPosition()
    turtle.turnRight()
    turtle.turnRight()
  end
  -- Unload extra fuel.
  for s = slotWood+1,16 do
    turtle.select(s)
    if turtle.getItemCount(s) > 0 then
      if not turtle.dropDown() then
        updateStatus("Fuel chest full. Waiting...")
        while not turtle.dropDown() do sleep(30) end
      end
    end
  end
  -- Unload extra wood
  for s = slotWood+1,16 do
    turtle.select(s)
    if turtle.compareTo(slotWood) then
      if not turtle.drop() then
        updateStatus("Inventory chest full. Waiting...")
        while not turtle.drop() do sleep(30) end
      end
    end
  end
  turtle.select(slotWood)
  turtle.drop(turtle.getItemCount(slotWood)-1)
  turtle.turnLeft()
  turtle.turnLeft()
  updateStatus("Finished servicing furnaces.")
end
function locateStartingPosition()
  -- Move down and forward until a chest or fence is located.
  local atHome = false
  -- In case stopped while servicing furnaces.
  if turtle.detectUp() or turtle.detectDown() then
    if not turtle.back() then
      turtle.turnRight()
      turtle.back()
    end
  end
  -- Now get down to the ground.
  while not turtle.detectDown() do turtle.down() end
  if aboveAChest() then
    print("Above a chest")
    while facingAChest() do
      turtle.turnRight()
    end
    print("At home")
    atHome = true
  end
  while not atHome do
    updateStatus("Looking for a chest")
    while not facingAChest() do
      refuel()
      while facingAFence() do
        turtle.turnRight()
        updateStatus("Found a fence")
      end
      if not goForward() then
        print("Can't go fwd")
        if isWood() then
          turtle.turnRight()
        elseif turtle.up() then
          if goForward() then
            if aboveAFence() then
              updateStatus("Found a fence")
              turtle.back()
              turtle.turnRight()
            end
          else
            turtle.turnRight()
          end
        else
          turtle.turnLeft()
        end
      end
      if aboveAFence() then
        updateStatus("Found a fence")
        turtle.back()
        turtle.turnRight()
      end
      while not turtle.detectDown() do turtle.down() end
    end
    updateStatus("Found a chest")
    -- Now we should be facing a Chest.
    if aboveAChest() then
      atHome = true
    else
      turtle.turnLeft()
      if facingAFence() then
        turtle.turnRight()
        break
      else
        turtle.turnRight()
        turtle.turnRight()
        if facingAFence() then
          turtle.turnLeft()
          break
        end
      end
    end
  end
  local overChests = true
  if not atHome then
    turtle.up()
    turtle.forward()
    sleep(.3)
    if not aboveAChest() then overChests = false end
    turtle.forward()
    sleep(.3)
    if not aboveAChest() then overChests = false end
    turtle.forward()
    turtle.down()
    sleep(.3)
    if not aboveAChest() then overChests = false end
  end
  if overChests then atHome = true else updateStatus("Lost a chest") end
  if atHome then
    -- Should now be in the home position.
    -- Now determine the correct orientation.
    local foundOpening = false
    for d=1,4 do
      if not facingAChest() then
        foundOpening = true
        updateStatus("In start position.")
        break
      end
      turtle.turnLeft()
    end
    if not foundOpening then
      while true do
        updateStatus("I'm lost and need help...")
        sleep(60)
      end
    end
  else
    while true do
      updateStatus("I'm lost and need help...")
      sleep(60)
    end
  end
end
function suckItUp(n)
  local d
  for d=1,4 do
    if n%2 == 0 then turtle.turnLeft() else turtle.turnRight() end
    turtle.suck()
  end
end

-- Program begins
updateStatus("Starting")
term.clear()
term.setCursorPos(1,1)
print("Velander's Tree Farmer "..version)
print("Turtle ID: "..minerID)
getConsoleID()
checkSetup()
local col = 0
local row = 0
local slot = 0
local leftShift = 0
fuelChestEmpty = false
locateStartingPosition()
abortCircuit = false

while true do
  -- Before we start planting make sure the turtle is properly equiped
  print("Checking fuel")
  if turtle.getItemCount(slotFuel) < 64 then
    -- Load up on fuel.
    print("Getting fuel "..64-turtle.getItemCount(slotFuel))
    turtle.select(slotFuel)
    if not turtle.suckDown(64-turtle.getItemCount(slotFuel)) then fuelChestEmpty = true end
  end
  -- Put back any extra fuel
  for d=1,16 do
    turtle.select(d)
    if d ~= slotFuel and turtle.compareTo(slotFuel) then turtle.dropDown() end
  end
  if fuelChestEmpty then serviceFurnaces() end
  if not refuel() then
    updateStatus("Out of fuel. Waiting.")
    while not refuel() do sleep(30) end
  end
  print("Checking bone meal")
  if turtle.getItemCount(slotBonemeal) < (treesPerRow * numberOfRows) then
    -- Load up on bonemeal if available.
    turtle.turnRight()
    -- Get enough bonemeal to fertilize all trees if necessary
    turtle.select(slotBonemeal)
    turtle.suck((treesPerRow * numberOfRows)-turtle.getItemCount(slotBonemeal)+1)
    turtle.turnLeft()
  end
  print("Checking saplings")
  local saplingCount = saplingsAvailable()
  if saplingCount <= (treesPerRow * numberOfRows) then
    turtle.turnLeft()
    turtle.select(slotSapling)
    while turtle.suck((treesPerRow * numberOfRows)-saplingCount+1) do
      saplingCount = saplingsAvailable()
      if saplingCount > (treesPerRow * numberOfRows) then break end
      turtle.select(slotSapling)
    end
    turtle.turnRight()
  end
  if saplingsAvailable() <= 1 then
    -- Out of saplings so restock from chest
    updateStatus("Out of saplings.")
  end
  local reachedEndOfCol = false
  local reachedEndOfRows = false
  local rowLength = 0
  local row = 1
  while not reachedEndOfRows do
    -- Move to beginning of grove.
    if row == 1 then
      moveForward()
      turtle.turnLeft()
      while not facingAFence() do
        moveForward()
        leftShift = leftShift + 1
      end
      moveBack()
      leftShift = leftShift - 1
      moveBack()
      leftShift = leftShift - 1
      turtle.turnRight()
    else
      turtle.turnRight()
      updateStatus("Moving to row "..row)
      for p=1,spaceBetweenTrees do
        if facingAFence() then
          reachedEndOfRows = true
          for l=1,p-1 do moveBack() end
          row = row - 1
          break
        else
          moveForward()
          suckItUp(p)
        end
      end
      if not reachedEndOfRows then
        moveBack()
        moveBack()
      end
      turtle.turnLeft()
    end
    if not reachedEndOfRows then
      updateStatus("Starting row "..row)
      reachedEndOfCol = false
      treesPerRow = 0
      rowLength = 0
      while not reachedEndOfCol do
        refuel()
        if abortCircuit then break end
        -- Move between trees sucking as you go.
        for p=1,spaceBetweenTrees do
          if facingAFence() then
            updateStatus("Found a fence in row "..row)
            reachedEndOfCol = true
          else
            moveForward()
            suckItUp(p)
            rowLength = rowLength + 1
          end
        end
        if facingAFence() then
          reachedEndOfCol = true
          moveBack()
          suckItUp(row)
          rowLength = rowLength - 1
        end
        if not reachedEndOfCol then
          treesPerRow = treesPerRow + 1
          turtle.turnRight()
          local found = false
          if turtle.detect() then
            -- Check to see if it is the wood we are harvesting
            if isWood() then
              updateStatus("Harvesting at "..row..","..treesPerRow)
              if refuel() then harvestTrunk() else abortCircuit = true end
            elseif facingAChest() then
              abortCircuit = true
            elseif facingAFence() then
              abortCircuit = true
            elseif turtle.detect() then
              updateStatus("Sapling at "..row..","..treesPerRow)
              found = true
              applyBonemeal()
              if isWood() then
                updateStatus("Harvesting at "..row..","..treesPerRow)
                if refuel() then harvestTrunk() else abortCircuit = true end
              end
            end
          end
          if not abortCircuit then
            if not isWood() and not isSapling() then
              if plantSapling() then
                updateStatus("Sapling planted at "..row..","..treesPerRow)
              end
            end
          end
          turtle.turnLeft()
        end
      end
      if abortCircuit then
        updateStatus("Aborting circuit.")
        turtle.turnLeft()
        turtle.turnLeft()
        locateStartingPosition()
        turtle.turnLeft()
        turtle.turnLeft()
        break
      else
        updateStatus("Reached end of row "..row)
        moveForward()
        suckItUp(row)
        rowLength = rowLength + 1
        turtle.turnRight()
        turtle.turnRight()
        -- returing to bottom of grove.
        for p=1,rowLength do
          suckItUp(p)
          moveForward()
        end
        turtle.turnLeft()
        moveForward()
        moveForward()
        turtle.turnLeft()
      end
      row = row + 1
    end
  end
  if not abortCircuit then
    numberOfRows = row
    -- Should be back to the begging of the grove at the last column of trees.
    turtle.turnLeft()
    -- Return to start
    updateStatus("Returning to start.")
    local sr = (spaceBetweenTrees * (numberOfRows-1))+2 - leftShift
    for p=1,sr do
      turtle.suck()
      if facingAChest() or facingAFence() then
        updateStatus("Lost. Returning to start.")
        locateStartingPosition()
        abortCircuit = true
        turtle.turnLeft()
        turtle.turnLeft()
      else
        moveForward()
      end
    end
    -- Should be back in the start position.
    if not abortCircuit then
      turtle.turnLeft()
      turtle.forward()
    end
  end
  abortCircuit = false
  if not facingAChest() or not aboveAChest() then
    locateStartingPosition()
    turtle.turnLeft()
    turtle.turnLeft()
  end
  -- Now facing inventory chest.
  updateStatus("Storing wood.")
  for slot=slotWood+1,16 do
    turtle.select(slot)
    local dropped = true
    if turtle.compareTo(slotSapling) then
      -- Leave for now
    elseif turtle.getItemCount(slot) > 1 then
      if not turtle.drop() then dropped = false end
    end
    if dropped and turtle.getItemCount(slotWood) > 1 then
      turtle.select(slotWood)
      if not turtle.drop(turtle.getItemCount(slotWood)-1) then dropped = false end
    end
    if not dropped and (furnaceCount == nil or furnaceCount > 0) then
      -- Inventory must be full.  Make sure that the furnaces are busy.
      updateStatus("Servicing furnaces...")
      turtle.turnRight()
      turtle.turnRight()
      refuel()
      serviceFurnaces()
      turtle.turnRight()
      turtle.turnRight()
      break
    end
  end
  turtle.turnRight()
  -- Now facing chest with saplings.  Unload extra saplings
  updateStatus("Storing saplings.")
  for slot=1,16 do
    turtle.select(slot)
    -- Check to see if it is a sapling
    if slot ~= slotSapling and turtle.compareTo(slotSapling) then
      if not turtle.drop() then
        updateStatus("Sapling chest full.")
        turtle.up()
        turtle.drop()
        turtle.down()
      end
    end
  end
  turtle.turnRight()
  -- Back in start position.
  updateStatus("Pausing before next circuit...")
  sleep(30)
end