Palm trees in Vancouver? Florida's climate in Burnaby? Plant fossils suggest region once had a warmer climate - Action News
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British Columbia

Palm trees in Vancouver? Florida's climate in Burnaby? Plant fossils suggest region once had a warmer climate

Paleobotanists and climatologists have identified the plant fossils unearthed at Simon Fraser University's construction site in the late 1960s, which they say allude to a much hotter climate around the coastal B.C. area around 40 million years ago.

The unearthed fossils, dating back to 40 million years ago, include a fragment from a palm leaf

A close-up of paleobotanist Rolf Mathewes holding a plant fossil, which shows a rock surface with markings of a leaf.
A new paleobotany study has verified the identities of ancient plant fossils first unearthed at Burnaby Mountain in the late 1960s during the construction of Simon Fraser University. The fossils give clues to the region's warmer ancient climate. (Simon Fraser University)

There was a time when Burnaby Mountain, and the areas around it along B.C.'s south coast,was a warmer, less mountainous region where palm trees grew, according to new research that identified plant fossils unearthed at the site more than 50 years ago.

When Simon Fraser University was being built in the late 1960s, paleobotanist Rolf Mathewes was an undergraduate, and he helped gather dozens of plant fossils at a deposit exposed by the construction site. The fossils date back to around 40 million years ago.

SFU then locked the specimens in cabinets, where they remained largely untouched for decades.

Now a professor at the universityand at the twilight of his career, Mathewes set out to revisit the plant fossils he helped collect.

"I thought, before I retire, I should really publish something on these fossils. They've never been published and never really been studied," said Mathewes.

Mathewes and his research teamverified the collectioncontained a mix of subtropical and temperate forest elements, giving clues about Burnaby Mountain's climate in the distant past.

The findings were published in theInternational Journal of Plant Sciences this month, looking into the plant fossils that date back to the late Eocene period. The Eocene lasted from 55.8 to 33.9 million years ago and is known for its warmer climate.

Palm trees once in B.C.?

Mathewes says asignificant fossil in the collection wasa palm leaf fragment. Palm trees can still be planted in B.C., but they can no longer thrive in the region.

"If you wanted to match what kind of climate they're telling us was here, the best match is somewhere around Cape Fear on the East Coast of the United States," said Mathewes.

Pictures of five plant macrofossils are labeled A to E. They are rock surfaces that contain leaf linings of varying shapes.
The research team collected an array of reproductive plant macrofossils from the Simon Fraser University construction site in the 1960s. The specimens remained unstudied until Rolf Mathewes set out to study them more than 50 years later. (Simon Fraser University)

Mathewes says a global cooling period that followed the Eocene era allowed for the palms in the area to be slowly replaced by temperate trees like elms and sweetgum.

"The palms can tolerate it here, but it's not warm and tolerant enough to make it into the forest."

The team also identified a hydrangea flower and a flower of an extinct plant related to the basswood, which is native to Eastern North America.

"Some of the things that turned up were amazingly surprising ... That includes some flowers and seeds of plants that don't grow here and are only found in either Asia or in eastern North America."

Mathewes also notes the Burnaby Mountain regionresembled a floodplain during the Eocene.

"It was a sea-level plain near the ocean with rivers and ponds and marshes on it, and that's where the fossils were produced," he said.

A black and white photo of younger Rolf Mathewes as an undergraduate at the fossil deposit is next to a colour photo of Mathewes at present day.
Paleobotanist Rolf Mathewes helped unearth the plant fossils as an undergraduate student in the late 1960s and returned to the fossil collection decades later as he neared retirement. (Simon Fraser University)

'A glimpse of ... what things might look like'

Kendra Chritz, an earth sciences professor at the University of British Columbiawho was not involved in the study, says finding the palm in the fossil locality gives further evidence of Metro Vancouver'sclimate being warm and humid around that period.

"If you think about places where palms grow naturally now like California, Florida or Mexico, imagine something like that but in British Columbia. It's very warm, very wet anddiverse," Chritz said.

Chritzsays it's important to study periods like the Eocene to help understand today's changing climate. She says the Eocene period had high levels of carbon dioxide, which could informtoday's increasing levels.

"This kind of gives us a glimpse of maybe what things might look like, but we also have to remember that this is well before we existed."

Chritz says human activities put a different context to a warming climate, when animals and plants cannot move around and adapt as easily as they did in the distant past.

Mathewessays he's happy to have revisited the fossils he helped collect decades ago. The study is dedicated tohis late mentor who oversaw the excavation, Robert C. Brooke.

"I'm glad I managed to finally finish analyzing the story with the help of my colleagues," Mathewes said.

"I should have done it years ago, but I was tied up."