Canada’s jack pine tree holds secrets in Branches
By Randy Boswell, Postmedia News December 28, 2010
It’s arguably Canada’s most recognizable artwork, a classic Tom Thomson landscape showing a lonely tree with drooping branches, toughing out its fragile existence on a rocky, northern lakeshore.
But The Jack Pine, a priceless public treasure that’s been on permanent display in the National Gallery of Canada for almost a century, depicts a species with long-held secrets that a team of Canadian scientists has just now unravelled.
After a comprehensive study of the boreal forest’s most iconic tree, three Quebec botanists who travelled thousands of kilometres across Eastern Canada collecting jack pine seeds have determined that the trees found in Nova Scotia, Ontario and Saskatchewan each represent genetically distinct families with separate histories shaped by glaciers from the last Ice Age.
That means the jack pines in Western Canada and the Maritimes evolved independently over the past 10 millenniums or so from the Ontario specimen that Thomson immortalized in his 1917 masterpiece from the shore of Algonquin Park’s Grand Lake.
The vast ice sheets that covered North America during the last continental freeze-up forced a general southward retreat of jack pine forests, fragmented their populations and “profoundly influenced their present-day distribution and genetic diversity,” the researchers, led by Universite de Laval scientist Julie Godbout, conclude in a summary of the study, published in the American Journal of Botany.
Godbout and her colleagues, Natural Resources Canada scientist Jean Beaulieu and fellow Laval researcher Jean Bousquet, probed the divergent jack pine lineages after collecting samples from more than 1,200 trees from conifer stands throughout eastern North America, including parts of New York, Vermont and Maine.
The jack pine’s “three-pronged ancestry,” they determined, indicates that an isolated pocket of trees in a “cryptic refugium” located somewhere along the Atlantic coast survived the last glacial invasion and gave rise to today’s genetically distinct form of the species – although the differences are not evident to the eye.
A similar separation of jack pine populations west of Ontario produced another genetically divergent branch of the family in that part of the boreal forest.
Godbout noted that the revelations about the jack pine may point to other plant species that experienced similar glacial separations and evolved multiple lineages.
She told Postmedia News that her years of scientific work on the tree captured in Thomson’s signature painting has given her a deep appreciation of the hardy species.
“Even if it looks like an old bonsai, jack pine is a real tough,” she said.
“It regenerates through fire – so each ‘baby’ tree is an orphan – it’s a real fast grower, and it can grow on rock and sand in difficult conditions,” qualities that are evident “when we look at the Thomson’s jack pine.”
She added: “I sometimes joke when we hike with my friends about an ’emotional’ way to differentiate the three pine species we have inEastern Canada. If it feels like a snob, it’s a white pine, if it looks rather nasty it’s a red pine – because of the long spines – and if you feel pity, it’s jack pine.”
At first glance, she observed, “it feels lonely and sad,” but the tree is really more like “an old sage that knows a lot about life and death.”
And it’s because of this “toughness,” she said, “that it was plausible to propose that jack pine may have survived in a cryptic refugium along the Atlantic coast.”
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