The origin of the saying might well be an 1894 report by the State Fish and Game Commissioner of North Dakota:

In 1894 the importance of conserving natural resources was recognized and expressed in a report by the State Fish and Game Commissioner of North Dakota. The report cautioned that short-term thinking and narrow monetary motivations might lead to the destruction of the “last tree” and the “last fish”. The following passage shows thematic similarities to the quotation under investigation:

"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."

Quote Investigator

LFF