Ladies and gentlemen, please welcome – the Yukon pine!
About three years ago, Environment Yukon biologist Bruce Bennett told Wayne Strong about some odd, smooth-barked lodgepole pines he'd noticed on Mount McIntyre, near Whitehorse. Strong, a Yukon-based forest ecologist, was busy with other research at the time, but he filed the comment away in his memory.
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The double trunk and the large, low branches mark this tree as a Yukon pine.
(photo: Wayne Strong)
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Last October, with his field season winding down, he went looking for the trees. And he found them, along the Fish Lake Road and on the western side of Mount McIntyre.
"The first place I happened to stop, I found one," Strong says. The tree was clearly a lodgepole pine, but it looked odd.
Interior lodgepole pine, the pine commonly found in the Yukon, has a single long, straight trunk covered with rough, coarse-scaled bark, and branches that start relatively high above the ground. Those long, branch-free trunks make the trees valuable sources of lumber for forestry companies in British Columbia and Alberta.
The trees Strong found on Mount McIntyre were different. They branched close to the ground, the branches were often long and substantial, and some trees even had two trunks.
Stranger still to the ecologist's eye, the trunks were covered with smooth, weakly-scaled bark. Strong searched the scientific literature, but couldn't find any reference to lodgepole pine with smooth bark. The difference in the bark is easy to spot, he says.
"It's like very coarse sandpaper compared to very fine sandpaper."
The trees had other peculiarities too. The needles of inland lodgepole pine normally come in bundles, or fascicles, of two. On the Yukon pines, three-needle fascicles were also common. And the trees were often shorter than expected for their age, although their trunks were thicker.
With winter coming on fast, Strong spent two chilly weeks hiking up and down slopes in the Whitehorse area in search of more specimens. And he found them – scattered singly over the subalpine slopes, at elevations above 1000 metres, on the west side of Mount McIntyre, near the Sumanik fire tower, and on Grey Mountain. In fact, he found enough of the trees to be convinced that they were something special: a variety of lodgepole pine new to science. That, for a scientist, is exciting.
"It's sort of a once-in-a-lifetime thing, especially when it comes to trees. You don't find many new types of trees," Strong says. "It's been 130 years since someone identified a new type of lodgepole pine."
Identifying and naming a new variety of plant is a formal and complicated procedure.
The first step, of course, is to find the tree. Then you give it a name. Strong chose a name to suit the new tree's location: the Yukon pine. In formal scientific terms, that's Pinus contorta Douglas ex Loudon var. yukonensis W.L. Strong.
After that comes the business of convincing the rest of the scientific world to accept the discovery. Strong wrote a scientific description of the new tree and collected specimens for deposit in an accredited herbarium. Those specimens will be the standard that future scientists use when studying the Yukon pine. Strong also had to get his scientific description translated into Latin, still the formal language accepted internationally for the naming of new plants.
Next came what is often the most difficult step. Strong had to write a scientific article describing the Yukon pine and laying out reasons why the scientific world should recognize it as a new variety of tree, and then get the article accepted by a recognized scientific journal.
Well, he's done it. Strong's article introducing the Yukon pine will appear in the Nordic Journal of Botany this fall. After that, he sits back and waits for his peers in the scientific world to pass judgement.
If the Yukon pine is accepted, it will bring the number of recognized varieties of lodgepole pine in North America to four. Lodgepole pine extends from Baja California in the south to the central Yukon in the north. In the east, the trees are found in the eastern foothills of the Rocky Mountains, and in the west, all the way to the Pacific Ocean.
Most lodgepole pine belong to the inland variety, but there are different varieties at the southern extreme of the tree's range and along the Pacific shore, where wind and salt create harsh conditions. It makes sense, Strong says, to find another variant at the northern edge of the tree's range, where high latitude and high elevation produce colder conditions than most lodgepole pine have to deal with.
In fact, he thinks the Yukon pine might be a native Yukon species. During the last ice age, lodgepole pines survived in unglaciated places like modern-day Wyoming, southern Montana, and Washington State. Strong thinks some might have weathered the glaciers in ice-free Beringia too. During thousands of years of isolation, they developed enough differences from their southern relatives to be a distinctive variant within the lodgepole pine population.
