Canada, the most affluent of countries, operates on a depletion economy which leaves destruction in its wake. Your people are driven by a terrible sense of deficiency. When the last tree is cut, the last fish is caught, and the last river is polluted; when to breathe the air is sickening, you will realize, too late, that wealth is not in bank accounts and that you can’t eat money.

As quoted in "Conversations with North American Indians" by Ted Poole in Who is the Chairman of This Meeting? : A Collection of Essays (1972) edited by Ralph Osborne, p. 43. In the article "When the Last Tree Is Cut Down, the Last Fish Eaten, and the Last Stream Poisoned, You Will Realize That You Cannot Eat Money", "Quote Investigator" states that Greenpeace placed a paraphrased approximation on a banner in 1981, which has been widely propagated as a "Cree prophesy" or "Cree saying" and alternately attributed directly to Obomsawin, as in "A Thought for the Day" at Wordsmith (8 October 2014)

When the last tree is cut, the last river poisoned, and the last fish dead, we will discover that we can’t eat money. | The article of the Quote Investigator states similar expressions had also been used by others around 1972, and the earliest incident found of somewhat similar expressions of the importance of conserving natural resources occurred in the "Biennial Report of the State Fish and Game Commissioner to the Governor of North Dakota from March 17, 1893 to December 1, 1894", By North Dakota's Superintendent of the Department of Irrigation and Forestry, William W. Barrett, to the Governor of the same state | Present needs and present gains was the rule of action — which seems to be a sort of transmitted quality which we in our now enlightened time have not wholly outgrown, for even now a few men can be found who seem willing to destroy the last tree, the last fish and the last game bird and animal, and leave nothing for posterity, if thereby some money can be made.