pollen records raise questions about pristine

Erling Friis-Baastad We tend to throw around the words "pristine" and "wilderness" readily in the Yukon.

Erling Friis-Baastad

We tend to throw around the words “pristine” and “wilderness” readily in the Yukon. For most of us, the terms conjure visions of boreal forest untouched by human activity, a landscape that appears much as it did a couple million years ago – minus the camels and mammoths.

However the hypothesis approached by a paper recently published by Quaternary Science Reviews suggests that our territory might not be as pristine as we like to believe and that what constitutes human impact could stand some serious reimagining.

Anthropologist Charles Schweger, professor emeritus with the University of Alberta, Edmonton, is a co-author, along with three other earth scientists, of “Pre-glacial and interglacial pollen records of the last 3 Ma from northwest Canada: Why do Holocene forests differ from those of previous interglacials?” While the paper was released only last year, the research behind it has been underway much longer, says Schweger, who began looking at Quaternary biology in the North in Alaska in the 1960s and in the Yukon in the 1970s.

The Quaternary Period, which began roughly two and a half million years ago, and contains the Pleistocene and the Holocene epochs, has been a time of repeated glaciations, ice ages, and interglacials, or warmer periods. In fact, our own “scene,” the Holocene – the last 10,000 years – is an interglacial.

Schweger and his colleagues collected data over four to five decades. Science usually arrives at its “eureka” moments only after the bits and pieces are gathered over time and by a number of scientists, he says. “You collect a little bit of data and you don’t quite know what it means so it you set aside, and a couple years later you’ve got more data, and … you set it aide.” Then one day, you look at all those little pieces and patterns begin to emerge, “relationships you couldn’t have foreseen.”

While we tend to think of the Quaternary in terms of its ice ages – mammoths trumpeting across frozen steppes – the period was punctured repeatedly by interglacials and not much work has yet been done on these. “The warm periods are almost easier to work with because they are easier to find in the field,” says Schweger. “You can easily recognize them when you’re doing geology because you’ll find buried peat deposits, evidence of trees … and that sort of thing. This indicates the climate was much warmer.”

The scientists who had turned their attention to the interglacials stumbled into a timely piece of research, an analogue for what the North might come to look like under climate change: “The kind of thing we might anticipate with global warming as northern latitudes warm up with the high CO2 concentrations in the atmosphere,” says Schweger.

“They want to know what the impact would be on vegetation, its composition and distribution, etc.” It’s a “predictive application,” with which scientists can try to link the past and present with the future, he says.

As with so many other Quaternary science projects, Schweger’s research took him into the Klondike gold fields, where miners had unearthed ancient sediments while digging for gold, and down to river valleys where moving water had cut away layers of earth. The exposed sediments contain fossilized pollens, among other treasures. With a microscope researchers can identify the species of vegetation that launched the pollens.

“For almost 3 million years we had forests that were dominated by spruce and fir and we know that the fir was so much, much more widespread in the Yukon and extended well up into the Old Crow Basin,” says Schweger. In our own time, however, fir has appeared over a much more limited range: the subalpine zones of mountains (such as Mt. Sima) to the south and central Yukon. The last 10,000 years have tended to exclude fir while favouring pine.

What happened? Well, one factor would have been the elimination of some ice age fauna, the extinction of the mammoths and other hungry beasts. These creatures grazed and browsed, ate some plants, trampled or tore down some plants, and fertilized others with nutrient-rich manure. “When the animals became extinct, the vegetation should have responded in some way.” But there was a glitch in this otherwise comfortable theory. “The problem,” says Schweger, “is we began to see pine appearing in the Yukon several thousand years after those animals became extinct.”

However, another creature was proliferating across the landscape, one who had mastered fire, and used it for cooking and preserving food, preparing hides, keeping warm, protection, signalling, bending wood for snowshoes and many other tasks, including, possibly, changing vegetation cover to favour moose, a major food source.

Fir is not a fire-adapted species. Pine is. In fact, it thrives in fire-cleared landscapes. By 2,000 to 1,500 years ago, pine had begun extending further north after the fir retreated. Schweger warns that the conclusion is actually a hypothesis, that more work remains to be done, especially on remnant charcoal, but it appears likely that human use of fire may have greatly changed the landscape.

Europeans showed up and suppressed wildfires, not understanding their importance in rejuvenating forests … a reason why we have so much “senile” old tree cover, prey to spruce beetles and then the massive forest fires of today, says Schweger.

“When we talk about vegetation across the North, it is so easy to say we have true wilderness,” he says. It’s easy to declare, “‘If you go to the Yukon, you will experience true wilderness. A landscape that’s been untouched by humans over a large area….’”

But the current research suggests that such preconceptions are wrong. People have been part of the Yukon landscape for thousands of years and have been capable of altering vegetation. “And it really makes us have to rethink this whole idea of what constitutes wildness and wilderness,” says the scientist.

This column is co-ordinated by the Northern Research Institute at Yukon College with major financial support from Environment Yukon and Yukon College/ The articles are archived at www.taiga.net/yourYukon.

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Crystal Schick/Yukon News
Calvin Delwisch poses for a photo inside his DIY sauna at Marsh Lake on Feb. 18.
Yukoners turning up the heat with unique DIY sauna builds

Do-it-yourselfers say a sauna built with salvaged materials is a great winter project

Wyatt’s World

Wyatt’s World for March 5, 2021.

Yukonomist: School competition ramps up in the Yukon

It’s common to see an upstart automaker trying to grab share from… Continue reading

The Yukon government responded to a petition calling the SCAN Act “draconian” on Feb. 19. (Yukon News file)
Yukon government accuses SCAN petitioner of mischaracterizing her eviction

A response to the Jan. 7 petition was filed to court on Feb. 19

City councillor Samson Hartland in Whitehorse on Dec. 3, 2018. Hartland has announced his plans to run for mayor in the Oct. 21 municipal election. (Crystal Schick/Yukon News file)
Councillor sets sights on mayor’s chair

Hartland declares election plans

Chief Medical Officer of Health Dr. Brendan Hanley receives his first dose of the COVID-19 vaccine from Public Health Nurse Angie Bartelen at the Yukon Convention Centre Clinic in Whitehorse on March 3. (Crystal Schick/Yukon News)
State of emergency extended for another 90 days

“Now we’re in a situation where we see the finish line.”

The Yukon government says it is working towards finding a solution for Dawson area miners who may be impacted by City of Dawson plans and regulations. (Joel Krahn/Yukon News file)
Miner expresses frustration over town plan

Designation of claims changed to future planning

Team Yukon athletes wave flags at the 2012 Arctic Winter Games opening ceremony in Whitehorse. The 2022 event in Wood Buffalo, Alta., has been postponed indefinitely. (Justin Kennedy/Yukon News file)
2022 Arctic Winter Games postponed indefinitely

Wood Buffalo, Alta., Host Society committed to rescheduling at a later date

Housing construction continues in the Whistle Bend subdivision in Whitehorse on Oct. 29, 2020. (Crystal Schick/Yukon News file)
Yukon Bureau of Statistics reports rising rents for Yukoners, falling revenues for businesses

The bureau has published several reports on the rental market and businesses affected by COVID-19

Council of Yukon First Nations grand chief Peter Johnston at the Yukon Forum in Whitehorse on Feb. 14, 2019. Johnston and Highways and Public Works Minister Richard Mostyn announced changes to the implementation of the Yukon First Nations Procurement Policy on March 3. (Crystal Schick/Yukon News file)
Third phase added to procurement policy implementation

Additional time added to prep for two provisions

Crews work to clear the South Klondike Highway after an avalanche earlier this week. (Submitted)
South Klondike Highway remains closed due to avalanches

Yukon Avalanche Association recommending backcountry recreators remain vigilant

RCMP Online Crime Reporting website in Whitehorse on March 5. (Haley Ritchie/Yukon News)
Whitehorse RCMP launch online crime reporting

Both a website and Whitehorse RCMP app are now available

A man walks passed the polling place sign at city hall in Whitehorse on Oct. 18, 2018. The City of Whitehorse is preparing for a pandemic-era election this October with a number of measures proposed to address COVID-19 restrictions. (Crystal Schick/Yukon News file)
City gets set for Oct. 21 municipal election

Elections procedures bylaw comes forward

Most Read