More Frequent Fires Could Dramatically Alter Boreal Forests And Emit More Carbon

More Frequent Fires Could Dramatically Alter Boreal Forests And Emit More Carbon A wildfire moves towards the town of Anzac from Fort McMurray, Alta. in May 2016. Jason Franson/The Canadian Press via AP

These days, smoke-filled summer skies and dusky red sunsets are a common occurrence across Canada and the United States. Much of that smoke is coming from large northern wildfires.

We have been working on the consequences of increasing boreal wildfires since 2004, when a huge swath (2.6 million hectares) of boreal forest burned in Alaska and the Yukon. It seemed, at the time, like an unusually large fire year. Since then, we have seen record breaking fire activity occur repeatedly across northern North America.

Increasing fire activity in the boreal forest is consistent with projected responses to climate change. This means that individual forests are likely to burn more frequently then they have in the past hundreds, even thousands, of years. Our research on forest responses to large fires shows that an increasing frequency of fire leads to a cascading set of changes that may substantially alter the boreal forest as we know it.

Impacts of more frequent fire

Boreal forests have acted as carbon sinks — they remove carbon dioxide from the atmosphere and store it in biological materials — for millennia. But our recent study of the 2014 fires in the Northwest Territories shows that some parts of the boreal forest are becoming sources of atmospheric carbon, potentially contributing to the greenhouse effect.

Recent estimates suggest that boreal forests store more carbon than is currently in the atmosphere, with most of that carbon found in soils. These pools of old soil carbon are contained in deeper soil layers and tend to stay wet. Historically, this has kept them safe from burning.

However, our work in the Northwest Territories shows that when young forests (less than 60 years old) burn, this old carbon — stored in previous fire cycles — is closer to the surface, making it about five times more likely to burn. Increasing fire frequency thus makes boreal forests more likely to release stored legacy carbon back to the atmosphere.

More Frequent Fires Could Dramatically Alter Boreal Forests And Emit More Carbon Boreal forest soils slowly build up stores of legacy carbon across multiple fire cycles, which can be released when fires burn in young forest stands. Victor O. Leshyk, Center for Ecosystem Science and Society, Northern Arizona University

Frequent burning also affects tree regeneration after fire, changing the tree species that dominate the forest canopy and potentially shifting some forest stands to tundra or open woodlands. Our work on forest recovery after the large fire years of 2004-05 in Alaska and Yukon shows that black spruce, the most abundant tree in North America’s boreal forest, quickly loses its home court advantage when fires become too frequent.

Black spruce is the quintessential slow-growing northern tree. It doesn’t produce its first seed crop until it is about 25 years old and it needs 50-80 years to reach full reproductive maturity.

Normally these spruce trees regenerate well after fire. They have the ability to “bank” seeds for the future by sealing them in cones. These cones open with fire and disperse many hundreds of seeds onto the landscape.

However, when black spruce forests burn at an early age, a safe bank of cones has not yet developed and the absence of seeds reduces spruce regeneration success. In the far North, repeat fires in black spruce forests can cause a shift from forest to tundra. In warmer parts of the boreal forest, spruce forests are replaced with deciduous trees like birch and aspen.

More Frequent Fires Could Dramatically Alter Boreal Forests And Emit More Carbon Young-burned black spruce forest regenerating to non-forested tundra. Carissa Brown

Losing legacies

When legacy carbon burns and black spruce regeneration fails, one of the boreal forest’s most important ecosystem services, the long-term storage of atmospheric carbon, is jeopardized.

In addition to storing carbon, the boreal forest provides critical habitat for wildlife species such as caribou that feed on lichens in mature conifer stands. Large herds of barren ground caribou that overwinter in the boreal forest have been a traditional food source for northern peoples for millenia.

Increases in fire that disrupt conifer forests and their lichen understory will likely have negative impacts on caribou populations and the people that depend on them. And once shifts from black spruce forests to aspen or tundra occur, these forests are slow to return to historic conditions, as the ingredients necessary to regenerate the original forests are now missing: legacy carbon seedbeds and a source of black spruce seed.

The impacts caused by a changing fire frequency can happen fast — loss of legacy carbon and shifts in tree species are triggered by single fire events — and will likely dwarf other impacts of climate change on boreal forests, like drought stress or stimulation of plant growth with a warmer, carbon-rich atmosphere.

Changes to boreal forests and their ecosystem services will impact the lifestyles and livelihoods of local people, as well as influence the future climate trajectory of our planet. As climate change intensifies and fire frequency continues to increase we are likely to see a greater area of boreal forests shifting from carbon sinks to carbon sources and large declines in old growth conifers by the end of the 21st century.

About The Author

Jill Johnstone, Adjunct Professor of Biology, University of Saskatchewan; Carissa Brown, Associate professor, Memorial University of Newfoundland, and Xanthe Walker, Postdoctoral Research Scientist, Northern Arizona University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Related Books

Life After Carbon: The Next Global Transformation of Cities

by Peter Plastrik , John Cleveland
1610918495The future of our cities is not what it used to be. The modern-city model that took hold globally in the twentieth century has outlived its usefulness. It cannot solve the problems it helped to create—especially global warming. Fortunately, a new model for urban development is emerging in cities to aggressively tackle the realities of climate change. It transforms the way cities design and use physical space, generate economic wealth, consume and dispose of resources, exploit and sustain the natural ecosystems, and prepare for the future. Available On Amazon

The Sixth Extinction: An Unnatural History

by Elizabeth Kolbert
1250062187Over the last half-billion years, there have been Five mass extinctions, when the diversity of life on earth suddenly and dramatically contracted. Scientists around the world are currently monitoring the sixth extinction, predicted to be the most devastating extinction event since the asteroid impact that wiped out the dinosaurs. This time around, the cataclysm is us. In prose that is at once frank, entertaining, and deeply informed, New Yorker writer Elizabeth Kolbert tells us why and how human beings have altered life on the planet in a way no species has before. Interweaving research in half a dozen disciplines, descriptions of the fascinating species that have already been lost, and the history of extinction as a concept, Kolbert provides a moving and comprehensive account of the disappearances occurring before our very eyes. She shows that the sixth extinction is likely to be mankind's most lasting legacy, compelling us to rethink the fundamental question of what it means to be human. Available On Amazon

Climate Wars: The Fight for Survival as the World Overheats

by Gwynne Dyer
1851687181Waves of climate refugees. Dozens of failed states. All-out war. From one of the world’s great geopolitical analysts comes a terrifying glimpse of the strategic realities of the near future, when climate change drives the world’s powers towards the cut-throat politics of survival. Prescient and unflinching, Climate Wars will be one of the most important books of the coming years. Read it and find out what we’re heading for. Available On Amazon

From The Publisher:
Purchases on Amazon go to defray the cost of bringing you InnerSelf.comelf.com, MightyNatural.com, and ClimateImpactNews.com at no cost and without advertisers that track your browsing habits. Even if you click on a link but don't buy these selected products, anything else you buy in that same visit on Amazon pays us a small commission. There is no additional cost to you, so please contribute to the effort. You can also use this link to use to Amazon at any time so you can help support our efforts.

 

enafarzh-CNzh-TWdanltlfifrdeiwhihuiditjakomsnofaplptruesswsvthtrukurvi

follow InnerSelf on

facebook icontwitter iconyoutube iconinstagram iconpintrest iconrss icon

 Get The Latest By Email

Weekly Magazine Daily Inspiration

LATEST VIDEOS

The Great Climate Migration Has Begun
The Great Climate Migration Has Begun
by Super User
The climate crisis is forcing thousands around the world to flee as their homes become increasingly uninhabitable.
The Last Ice Age Tells Us Why We Need To Care About A 2℃ Change In Temperature
The Last Ice Age Tells Us Why We Need To Care About A 2℃ Change In Temperature
by Alan N Williams, et al
The latest report from the Intergovernmental Panel on Climate Change (IPCC) states that without a substantial decrease…
Earth Has Stayed Habitable For Billions Of Years – Exactly How Lucky Did We Get?
Earth Has Stayed Habitable For Billions Of Years – Exactly How Lucky Did We Get?
by Toby Tyrrell
It took evolution 3 or 4 billion years to produce Homo sapiens. If the climate had completely failed just once in that…
How Mapping The Weather 12,000 Years Ago Can Help Predict Future Climate Change
How Mapping The Weather 12,000 Years Ago Can Help Predict Future Climate Change
by Brice Rea
The end of the last ice age, around 12,000 years ago, was characterised by a final cold phase called the Younger Dryas.…
The Caspian Sea Is Set To Fall By 9 Metres Or More This Century
The Caspian Sea Is Set To Fall By 9 Metres Or More This Century
by Frank Wesselingh and Matteo Lattuada
Imagine you are on the coast, looking out to sea. In front of you lies 100 metres of barren sand that looks like a…
Venus Was Once More Earth-like, But Climate Change Made It Uninhabitable
Venus Was Once More Earth-like, But Climate Change Made It Uninhabitable
by Richard Ernst
We can learn a lot about climate change from Venus, our sister planet. Venus currently has a surface temperature of…
Five Climate Disbeliefs: A Crash Course In Climate Misinformation
The Five Climate Disbeliefs: A Crash Course In Climate Misinformation
by John Cook
This video is a crash course in climate misinformation, summarizing the key arguments used to cast doubt on the reality…
The Arctic Hasn't Been This Warm For 3 Million Years and That Means Big Changes For The Planet
The Arctic Hasn't Been This Warm For 3 Million Years and That Means Big Changes For The Planet
by Julie Brigham-Grette and Steve Petsch
Every year, sea ice cover in the Arctic Ocean shrinks to a low point in mid-September. This year it measures just 1.44…

LATEST ARTICLES

green energy2 3
Four Green Hydrogen Opportunities for the Midwest
by Christian Tae
To avert a climate crisis, the Midwest, like the rest of the country, will need to fully decarbonize its economy by…
ug83qrfw
Major Barrier to Demand Response Needs to End
by John Moore, On Earth
If federal regulators do the right thing, electricity customers across the Midwest may soon be able to earn money while…
trees to plant for climate2
Plant These Trees To Improve City Life
by Mike Williams-Rice
A new study establishes live oaks and American sycamores as champions among 17 “super trees” that will help make cities…
north sea sea bed
Why We Must Understand Seabed Geology To Harness The Winds
by Natasha Barlow, Associate Professor of Quaternary Environmental Change, University of Leeds
For any country blessed with easy access to the shallow and windy North Sea, offshore wind will be key to meeting net…
3 wildfire lessons for forest towns as Dixie Fire destroys historic Greenville, California
3 wildfire lessons for forest towns as Dixie Fire destroys historic Greenville, California
by Bart Johnson, Professor of Landscape Architecture, University of Oregon
A wildfire burning in hot, dry mountain forest swept through the Gold Rush town of Greenville, California, on Aug. 4,…
China Can Meet Energy and Climate Goals Capping Coal Power
China Can Meet Energy and Climate Goals Capping Coal Power
by Alvin Lin
At the Leader’s Climate Summit in April, Xi Jinping pledged that China will “strictly control coal-fired power…
Blue water surrounded by dead white grass
Map tracks 30 years of extreme snowmelt across US
by Mikayla Mace-Arizona
A new map of extreme snowmelt events over the last 30 years clarifies the processes that drive rapid melting.
A plane drops red fire retardant on to a forest fire as firefighters parked along a road look up into the orange sky
Model predicts 10-year burst of wildfire, then gradual decline
by Hannah Hickey-U. Washington
A look at the long-term future of wildfires predicts an initial roughly decade-long burst of wildfire activity,…

 Get The Latest By Email

Weekly Magazine Daily Inspiration

New Attitudes - New Possibilities

InnerSelf.comClimateImpactNews.com | InnerPower.net
MightyNatural.com | WholisticPolitics.com | InnerSelf Market
Copyright ©1985 - 2021 InnerSelf Publications. All Rights Reserved.