flog2

local offset = 0

local function fellTree()
  turtle.dig()
  turtle.forward()
  local height = 0
  while ( turtle.detectUp() ) do
    turtle.dig()
    turtle.digUp()
    turtle.up()
    height = height + 1
  end

  turtle.turnRight()
  turtle.dig()
  turtle.forward()
  turtle.turnLeft()

  for i=1,height do
    turtle.dig()
    turtle.digDown()
    turtle.down()
  end
  turtle.dig()

  turtle.turnLeft()
  turtle.forward()
  turtle.turnLeft()
  turtle.forward()
  turtle.turnLeft()
  turtle.turnLeft()
end

local function plant()
  turtle.up()
  turtle.forward()
  turtle.turnRight()
  turtle.select(2)
  for i=1,4 do
    turtle.suckDown()
    turtle.placeDown()
    turtle.forward()
    turtle.turnLeft()
  end
  turtle.turnRight()
  turtle.forward()
  turtle.turnRight()
  turtle.turnRight()
  turtle.down()
end

local function moveToSuck()
  turtle.turnLeft()
  turtle.forward()
  turtle.turnLeft()
  turtle.forward()
  turtle.forward()
  turtle.turnLeft()
  turtle.down()
end

local function moveFromSuck()
  turtle.turnLeft()
  turtle.forward()
end

local function suckWalk(dist)
  for i=1,dist do
    turtle.suck()
    turtle.turnRight()
    turtle.suck()
    turtle.turnLeft()
    turtle.turnLeft()
    turtle.suck()
    turtle.turnRight()
    turtle.forward()
  end
end

local function suckRound()
  for i=1,4 do
    suckWalk(3)
    turtle.turnLeft()
    suckWalk(2)
  end
end

local function findNextTree()
  turtle.up()
  turtle.select(1)
  turtle.turnRight()
  for i=1,10 do
    if (turtle.forward()) then
      offset = offset + 1
    else
      turtle.down()
      return false
    end
    turtle.turnLeft()
    if turtle.detect() then
      turtle.down()
      return true
    else
      turtle.turnRight()
    end
  end
  turtle.down()
  return false
end

local function returnToStart()
  turtle.turnLeft()
  turtle.turnLeft()
  while (offset > 0) do
    turtle.forward()
    offset = offset - 1
    turtle.suckDown()
  end
  turtle.turnRight()
end

local function unload()
  for i=3,16 do
    turtle.select(i)
    turtle.dropDown()
  end
end

local function refuel()
  turtle.select(1)
  while ((turtle.getFuelLevel() < 200) and (turtle.getItemCount(1) > 1)) do
    turtle.refuel(1)
  end
end

local function fellRow()
  refuel()
  while (findNextTree()) do
    fellTree()
    plant()
  end
  returnToStart()
  unload()
end

while (true) do
  fellRow()
  sleep(60)
end