Ontario Forest © Christopher Meder - Fotolia

Ontario Forests Will Be Net Carbon Source Until 2040

The “State of Ontario’s Forests” report stresses the need to understand the impacts of climate change on Crown forests – and their role in mitigating it.

Ontario’s Crown forests are expected to remain a net source of carbon emissions for the next three decades, according to the latest forestry report from the Ministry of Natural Resources.

Ontario’s Crown forests are expected to remain a net source of carbon emissions for the next three decades, according to the latest forestry report from the Ministry of Natural Resources.

The latest State of Ontario’s Forests report released January 3 – the third issued by the government, this one covering the fiscal years 2004 to 2008 – found that Ontario’s Crown forests will remain a carbon source until at least 2040 largely because of deforestation and decomposition of deceased and aging trees.

After 2040, changes to forest structure will see them become carbon sinks until 2100.

Ontario’s parks and forest areas cover approximately 10 per cent of the province’s entire landmass, storing more than six billion tonnes of carbon as of 2010.

Average temperatures in the province have increased by 1.4°C since 1948. And while the report states that extreme weather instances between 2004 and 2008 were rare, increasing temperatures, “combined with increased extreme weather events forecast to occur as a result of climate change, are expected to affect the composition, structure, and function of Ontario’s ecosystems.”

The dangerous effects of a warming climate on Canadian forests have been seen nowhere more clearly than in western Canada where the mountain pine beetle outbreak spread to over 14 million hectares by 2008, killing roughly 50 per cent of British Columbia’s mature lodgepole pine. By 2015, that percentage is expected to grow to 70 per cent.

Capable of crossing mountain ranges and lacking its most potent nemesis – a thorough and extended cold spell during winter months – the destructive insect has ravaged entire forests and expanded its palette from lodgepole to jack pine.

“If the mountain pine beetle reaches Ontario it could have major implications on Ontario’s forests,” the report warns.

Deforestation is another indicator of forest carbon emissions. Between 2001 and 2007, deforestation in southern Ontario alone denuded 8,856 hectares, outstripping afforestation efforts that added only 5,422 hectares over an eight year period from 2001 to 2009.

(Realizing that more trees planted would increase the volume of carbon sequestered, in May 2008 the government embarked upon the 50 Million Trees program, an effort to plant 50 million trees on private land in southern Ontario by 2025. The aim is to improve forest cover and remove an estimated 6.6 megatonnes of carbon dioxide from the atmosphere by 2050. To date, 15.8 million trees have been planted.)

Yet the MNR cannot speak with authority on how Ontario’s Crown forests will affect and be impacted by a warming climate, given that the ministry is still assessing both the vulnerability of Ontario’s forests to climate change and their potential to mitigate greenhouse gas emissions via their ability to act as a carbon sink.

On the vulnerability of the province’s Crown forests: “Understanding the adaptive capacity of our forests and examining the need for our assistance in helping species adapt will be crucial to ensuring the future health and resilience of our forests,” the report states.

In terms of carbon storage, the government remains hopeful that carbon will remain stored in wood products made from harvested trees, though “further research and analysis are required to determine the mitigation potential of these activities at the landscape and stand level,” they write.

While there are no formal public consultations on the forest update scheduled, the report states that the ministry welcomes public comments and questions on the study. You can email the Ministry of Natural Resources at sof.mnr@ontario.ca.


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Andrew is a freelance environmental writer and reporter based in Toronto with a Masters in Geography from the University of Toronto. When he’s not writing he’s usually cycling around town, thinking about what to write next. Andrew’s posts appear weekly on Thursdays. You can read more of Andrew’s stuff at his own blog, The Reeves Report, or follow him on Twitter.

Andrew Reeves is the Editor-in-Chief of Alternatives Journal. Overrun, his book about Asian carp in North America, will be published in Spring 2019 by ECW Press. His work has also appeared in the Globe & MailSpacing and Corporate Knights. Follow him on Twitter.