Regina researchers use tree rings to explain past, predict future

Dave Sauchyn said trees show a long period of drought could be in the Prairies future.

Dave Sauchyn says trees show a long period of drought could be in the Prairies future

Senior Research Scientist at the Prairie Adaptation Research Collaborative at the UofR Dave Sauchyn. (Dave Sauchyn/Submitted to CBC)

It's hard to predict the weather, but University of Regina researchers are using trees to trace weather patterns from the past and give insight into what Saskatchewan's climate might look like in the future.

Dave Sauchyn, senior research scientist at the Prairie Adaptation Research Collaborative, said prairies trees have plenty of lights, carbon dioxide, good soil, and nutrients. What varies year-to-year is water.

"The amount of tree growth each year depends on how much water was in the soil," he said on CBC's Afternoon Edition.

"There are trees that are hundreds, even thousands of years old," Sauchyn said. "So by measuring the growth every year, we can figure out how much water has been in the soil, the lakes, and the rivers over the past 1,000 years."

A student takes a sample from a tree to study its rings. (Dave Sauchyn/Submitted to CBC)

To get information on Saskatchewan, researchers look to the Rocky Mountains in Alberta because they are older, but also because that's where most of the people in Saskatchewan get their water.

"It's revealed that there are fairly consistent climate cycles. There is a cycle on the order of years and we know that's the result of El Niño and La Niña," he said.

"It's like a double whammy where you have a lack of rainfall for 15 years, but its occurring during a period of warmer summers." - Dave Sauchyn , Senior Research Scientist at the Prairie Adaptation Research Collaborative 

​Sauchyn said the cycle that scientists are only starting to understand is in terms of decades. Typically there are a couple decades of drier weather and a couple of wetter weather, which researchers, using some tree ring data, have recently linked to the circulation of the Pacific Ocean.

A lot of stakeholders are interested in the findings because it will give insight into what a future, serious drought could look like, according to Sauchyn.

"We find droughts that are 10, 15, 20 years long in the tree rings and there is no reason they can't reoccur," he said.

"To understand why they occur we collaborate with other scientists who have models and measurements of the climate system. If they tie together the long perspective of the climate with the study of the present climate, we can begin to tease out what causes these natural cycles to occur, and how are they changing in a period of global warming."

The most threatening scenario that could play out, according to the tree ring findings, would be a long-term drought in a warmer global climate.

"It's like a double whammy where you have a lack of rainfall for 15 years, but its occurring during a period of warmer summers. So it's like global warming is sort of compounding the problem," he said.

According to their website, the Prairie Adaptation Research Collaborative is a partnership of the governments of Canada, Alberta, Saskatchewan, and Manitoba with a mandate to pursue climate change impacts and adaptation research in the Prairies.


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