Michael Perelman is right that the math valuation formula for which we
remember Faustmann leaves out ecology. Remember, though, that he was
debating with other forest economists who were doing the same thing to
simplify their subject. I do not know to what extent he or others considered
other forest services and products in other writings. One should research
that question separately, though, before judging Faustmann to have been a
monomaniacal mathematician. He was a better mathematician than his rivals,
that is clear; but he may also have loved "to hear the little brook
a-gurgling, and listen to the merry village chime."

Mason Gaffney