local log = 1

turtle.select(log)
 -- if the tree has grown
    if turtle.compare() then
      turtle.dig()
      turtle.forward()
      -- harvest the tree
      while turtle.detectUp() do
      turtle.digUp()
      turtle.up()
      end
      -- return to the ground
      while not turtle.detectDown() do
        turtle.down()
      end
		turtle.back()
    end