Pehr Kalm born 1716 (d. 1779) was born in Sweden by Finish parents. He was a trained scientist, botanist, naturalist as well as agricultural economist and one of Carl von Linné (Linnaeus) followers. 1747 Pehr Kalm was payed by Royal Swedish Academy of Science to register information as well as bringing back plants and seeds to Sweden.
In 1750 Peter Kalm visited the area around todays Quebec. He edited 3 volumes, one nr 4 was edited after his death from notes he made. Some of the information he presents in his work where he notes what he saw in 1750. An English translation was made in 1966. Title: The America of 1750 : Peter Kalm’s travels in North America.
* During his trip in 1750 found Peter Kalm 180-190 years old white pines in Bay St. Paul (near Quebec)
as seen in the image below, the pine is not naturally occurring in NA.
source: Pinus Sylvestris, Linneaus Flora
180-190 years is still borderline because they could be planted by Cartier in 1534
* But when Kalm tells that he in 1750 saw 230 years old the red pines dated from counting of tree rings, those pines that aren’t native in NA can’t possibly be linked to any known European explorer.
That tree must have been planted at least 4 years before Verrazzanos made his exploration journey form Florida up to Nova Scotia in 1524. And Verrazzanos never made in inlands nor did he follow for example Hudson River north.
* But the real smoking gun was a Oak tree planted 251 years before Kalm’s voyage in 1750. Oak never was native in NA and that tree was planted latest 1499.