Forest fire smoke invades Manitoba skies

Thick smoke from neighbouring forest fires has been lingering over Manitoba 
but experts say it’s unlikely to impact plant growth

Thick smoke moved through Manitoba last week, creating air quality concerns and reduced visibility to two kilometres in some areas.

Manitoba has been blanketed in smoke for more than a week as forest fires continued to spread across Western Canada.

Drought-like conditions across the Canadian Prairies culminated to cause 395 active fires in Alberta, Saskatchewan, Manitoba and the Northwest Territories by Monday morning.

Air quality warnings have been issued almost daily and some producers may have been slowed by the reduced visibility caused by smoke and dense fog in some areas.

But although lingering smoke clouds may be a nuisance and a safety hazard, experts suggest they likely have little effect on crops.

University of Manitoba professor of cropping systems and natural systems agriculture, Martin Entz, said that while the haze may hinder photosynthetic rates, it won’t have much of an impact on plant growth.

“Of the few studies available on the subject, it appears that smoke from forest fires can indeed reduce photosynthetic rates in plants,” said Entz. “In one study, photosynthesis was reduced by 50 per cent, but growth rates were not affected. I suspect that the general high light intensity and long days in Manitoba result in very little negative effect of smoke on plant growth and eventual yield.”

An image captured by NASA shows the thick smoke stream moving into Manitoba from Saskatchewan.
An image captured by NASA shows the thick smoke stream moving into Manitoba from Saskatchewan. photo: NASA

Different biochemistry

Entz notes that the haze would act similar to a heavy cloud cover, although the biochemistry is different.

“Cloudy places like southern England and northern Europe produce the highest wheat yields in the world. This implies that lower light intensity may not be such a large factor in areas where day length is so great,” said Entz.

Weather specialists have also stated that the smoke may in fact benefit dry areas of the province as layers of haze keep the temperatures low while still providing solar light and elevating humidity levels.

The majority of the smoke is streaming from 114 active fires burning in Saskatchewan, 51 of which cover an area greater than 100 hectares each.

The largest fire is burning in central Saskatchewan near Prince Albert National Park, burning an area equivalent of 9,000 football fields.

As of July 6, 7,900 Saskatchewan residents have been ordered to evacuate their homes and the Canadian Armed Forces had been called in to assist firefighters in the area.

Manage vegetation

According to Manitoba Conservation Wildfire Program, there have been 289 fires reported in Manitoba to date that have affected 26,409 hectares. Manitoba averages 544 wildfires every year.

Farmers who own property near forest fire risk areas are encouraged to manage vegetation along fencelines and ditches, store bales in a few different locations to minimize loss and livestock owners should prepare an evacuation plan as a precaution.

For more information on how to prepare your acreage as well as a home and site hazard assessment, view this downloadable pdf courtesy of the Manitoba government.

About the author


Jennifer Paige

Jennifer Paige is a reporter centred in southwestern Manitoba. She previously wrote for the agriculture-based magazine publisher, Issues Ink and was the sole-reporter at the Minnedosa Tribune for two years prior to joining the Manitoba Co-operator.



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