chopTree

function fuelUp()
  if turtle.getFuelLevel() == 0 then
    turtle.select(1)
    turtle.refuel(1)
    print("Refueling...")
    print("Current fuel level: " .. turtle.getFuelLevel())
  end

  if turtle.getFuelLevel() == 0 then
    print("No fuel in slot 1.")
    chopping = false
   end
end

active = true
chopping = true
counter = 0

turtle.dig()
fuelUp()
turtle.forward()

while active do
  fuelUp()

  if turtle.detectUp() then
    turtle.digUp()
    turtle.up()
    counter = counter + 1
  else
    chopping = false
    print("Done chopping.")
  end

  if chopping == false then
    while turtle.detectDown() == false do
      fuelUp()
      turtle.down()
    end
    active = false
    print("")
    print("Job's done.")
    print("Chopped " .. counter .. " items.")
    print("Fuel remaining: " .. turtle.getFuelLevel())
  end
end