Controlled burning of natural environments could help offset our carbon emissions

[Renaud de RICHTER]

Controlled burning of natural environments could help offset our carbon emissions

phys.org/news/2021-12-natural-environments-offset-carbon-emissions.html

December 23, 2021

by University of Cambridge

Planting trees and suppressing wildfires do not necessarily maximize the carbon storage of natural ecosystems. A new study has found that prescribed burning can actually lock in or increase carbon in the soils of temperate forests, savannahs and grasslands.

The finding points to a new method of manipulating the world's natural capacity for carbon capture and storage, which can also help to maintain natural ecosystem processes. The results are published today in the journal Nature Geoscience.

"Using controlled burns in forests to mitigate future wildfire severity is a relatively well-known process. But we've found that in ecosystems including temperate forests, savannahs and grasslands, fire can stabilize or even increase soil carbon," said Dr. Adam Pellegrini in the University of Cambridge's Department of Plant Sciences, first author of the report.

He added: "Most of the fires in natural ecosystems around the globe are controlled burns, so we should see this as an opportunity. Humans are manipulating a process, so we may as well figure out how to manipulate it to maximize carbon storage in the soil."

Fire burns plant matter and organic layers within the soil, and in severe wildfires this leads to erosion and leaching of carbon. It can take years or even decades for lost soil carbon to re-accumulate. But the researchers say that fires can also cause other transformations within soils that can offset these immediate carbon losses, and may stabilize ecosystem carbon.

Fire stabilizes carbon within the soil in several ways. It creates charcoal, which is very resistant to decomposition, and forms 'aggregates' – physical clumps of soil that can protect carbon-rich organic matter at the center. Fire can also increase the amount of carbon bound tightly to minerals in the soil.

"Ecosystems can store huge amounts of carbon when the frequency and intensity of fires is just right. It's all about the balance of carbon going into soils from dead plant biomass, and carbon going out of soils from decomposition, erosion, and leaching," said Pellegrini.

When fires are too frequent or intense—as is often the case in densely planted forests—they burn all the dead plant material that would otherwise decompose and release carbon into the soil. High-intensity fires can also destabilize the soil, breaking off carbon-based organic matter from minerals and killing soil bacteria and fungi.

Without fire, soil carbon is recycled—organic matter from plants is consumed by microbes and released as carbon dioxide or methane. But infrequent, cooler fires can increase the retention of soil carbon through the formation of charcoal and soil aggregates that protect from decomposition.

The scientists say that ecosystems can also be managed to increase the amount of carbon stored in their soils. Much of the carbon in grasslands is stored below-ground, in the roots of the plants. Controlled burning, which helps encourage grass growth, can increase root biomass and therefore increase the amount of carbon stored.

"In considering how ecosystems should be managed to capture and store carbon from the atmosphere, fire is often seen as a bad thing. We hope this new study will show that when managed properly, fire can also be good—both for maintaining biodiversity and for carbon storage," said Pellegrini.

The study focused on carbon stored in topsoils, defined as those less than 30cm deep. More carbon is stored in the world's soil than in the global vegetation and the atmosphere combined. Natural fires occur in most ecosystems worldwide, making fire an important process in global carbon cycling.

More information: Adam Pellegrini, Fire effects on the persistence of soil organic matter and long-term carbon storage, Nature Geoscience (2021). DOI: 10.1038/s41561-021-00867-1. www.nature.com/articles/s41561-021-00867-1

[Tom Goreau]

In a forest fire most carbon goes off as CO2 or sits on the ground as char. The quality of the char depends on the starting materials and physical conditions of the burn, but a small (about a percent) but highly variable fraction turns into high grade biochar or black carbon, and that lasts essentially forever in the soil. In every place where forests were cleared for agriculture and pastures, fire-produced biochar makes up a major part of soil carbon, often around half. These char-rich dark colored soils have been traditionally sought by shifting Indigenous farmers in Africa, Asia, and South America for thousands of years, so it’s really a confirmation of ancient knowledge.

 

Thomas J. F. Goreau, PhD
President, Global Coral Reef Alliance

Chief Scientist, Blue Regeneration SL
President, Biorock Technology Inc.

Technical Advisor, Blue Guardians Programme, SIDS DOCK

37 Pleasant Street, Cambridge, MA 02139

gor...@globalcoral.org
www.globalcoral.org
Skype: tomgoreau
Tel: (1) 617-864-4226 (leave message)

 

Books:

Geotherapy: Innovative Methods of Soil Fertility Restoration, Carbon Sequestration, and Reversing CO2 Increase

http://www.crcpress.com/product/isbn/9781466595392

 

Innovative Methods of Marine Ecosystem Restoration

http://www.crcpress.com/product/isbn/9781466557734

 

No one can change the past, everybody can change the future

 

Those with their heads in the sand will see the light when global warming and sea level rise wash the beach away

 

Geotherapy: Regenerating ecosystem services to reverse climate change

 

 

 

From: <carbondiox...@googlegroups.com> on behalf of Renaud de RICHTER <renaud.d...@gmail.com>
Date: Friday, December 24, 2021 at 5:11 AM
To: Carbon Dioxide Removal <carbondiox...@googlegroups.com>
Subject: [CDR] Controlled burning of natural environments could help offset our carbon emissions

 

Controlled burning of natural environments could help offset our carbon emissions

phys.org/news/2021-12-natural-environments-offset-carbon-emissions.html

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[Tom Goreau]

While burning increases long lived carbon in soil, it also runs down nitrogen and sulfur, lost as gases, so the soil becomes steadily more limited in these essential elements in each burning cycle.

 

With modern biochar kilns about half the biomass carbon can be converted into long lived biochar, as opposed to around 1% in an uncontrolled forest fire, and the volatiles and energy captured too. This speeds up soil carbon storage about 50 times! And if there are suitable rock powder, biomass storage will be greatly stimulated too!

 

This could be done wherever invasive weeds have ruined the landscape, there is an incredible amount of abandoned land in many places.

[Ronal Larson]

List,  Renaud and Tom 

This is a multiple response to especially Renaud de Richter.  First, one new name (Kelpie Wilson), then my comments in responding to private-public messages from Tom Goreau and Renaud, Lastly, a repeat of the two original message on controlled burns from Renaud and Tom

My main thought is that Dr.  Pellegrini has done a fine job talking about an important subject that supports biochar.  But I wish that paper had also compared controlled burns with biochar.  Biochar seems to me to be much the superior option. 

 I could not find that Dr.  Pellegrini has written on biochar.  He previously was with Robert Jackson at Stanford, also an expert in this field and last author of this particular paper recommended by Renaud.  Unfortunately not much either from Professor Jackson on biochar - especially as an option to controlled burns

1.   Main new point.  

a.  There is one biochar person who has been concentrating on this topic - Kelpie Wilson.

Her site

 https://wilsonbiochar.com/

is full of information on how and why to make biochar (implicitly - instead of conservation burns).

b.   Kelpie is putting on a webinar in about 5 weeks on this topic.  

 I’ve signed up ($54+ cost) -  because she will be talking about the global economics of this approach to biochar as well as the several ways to do this.  

Free extras if you live near her in Oregon

        c.   There are others doing this of course.  Some are co-authors with Kelpie of a chapter in a free recent well done lengthy report, with Principal Author Dr. Jim Amonette,

See chapters 4 and 5  at:

https://csanr.wsu.edu/biomass2biochar/

d.  This has been a popular topic on the USBI website

 www.biochar-US.org

- especially reporting on USFS - sponsorship with USBI help of commercial demonstrations of several types. of mobile biochar production equipment topic introduced by Renaud below)

e.  This use of biochar to replace conservation burns work is going on in other countries - especially Australia.

f.    We’ll see whether Kelpie compares biochar to controlled burns directly and especially re economics.  My guess is she will

g.  One other authority on the comparisons of the two is Dr. Thea Whitman - one of my favorite biochar authors.  Nice story on controlled burns at 

https://grow.cals.wisc.edu/departments/features/controlled-burn

-  AND  turning to several more recent comments in or almost in this “Pellegrini” thread.

2.  From Tom G. - privately with Renaud (message #3) - but I think intended for full CDR list.    RWL agrees with Tom G.

 

On Dec 24, 2021, at 7:07 AM, Tom Goreau <gor...@globalcoral.org> wrote (responding to Renaud and myself):

YES! We need cost-effective mobile units for small local applications and minimal transport from source to sink.

 

<snip - for clarity>

3.   From Renaud - also only to Tom and myself - But I am sure also intended for this list

Ron,

I wonder if "mobile" hovens to make biochar in-situ could be cost effective (less than $30-40/ton) instead of open fires whose yield will be much lower? Of course it will always be more expensive than "controlled burning", but also less risky in case of the "control" of the fire fails

RWL3:  Yes - all correct.  Costs of course generally higher, but in developing countries - can be less.   I am also responding to Renaud in first paragraphs.

4.  Just a few opening lines of the first in this series - so as to see why the name Pellegrini is prominent.  No need for new comments by me here.

Le ven. 24 déc. 2021 à 15:04, Tom Goreau <gor...@globalcoral.org> a écrit :

While burning increases long lived carbon in soil, it also runs down nitrogen and sulfur, lost as gases, so the soil becomes steadily more limited in these essential elements in each burning cycle.

 

<snip>

From: Tom Goreau <gor...@globalcoral.org>
Date: Friday, December 24, 2021 at 8:55 AM

In a forest fire most carbon goes off as CO2 or sits on the ground as char. The quality of the char depends on the starting materials and physical conditions of the burn, but a small (about a percent) but highly variable fraction turns into high grade biochar or black carbon, and that lasts essentially forever in the soil. In every place where forests were cleared for agriculture and pastures, fire-produced biochar makes up a major part of soil carbon, often around half. These char-rich dark colored soils have been traditionally sought by shifting Indigenous farmers in Africa, Asia, and South America for thousands of years, so it’s really a confirmation of ancient knowledge.

 

<SNIP>

RWL4.   This last (next) partial message was first in this thread.  All this above so we might be sure the discussion is about both biochar and the topic of this Pellegrini paper. (which is clearly not as carbon negative as is biochar.).  I think Renaud’s intent (see above #3) was to ask for this comparison - which is not yet complete.  Thanks to Renaud for bringing the Pellegrini paper to our attention.

Ron

From: <carbondiox...@googlegroups.com> on behalf of Renaud de RICHTER <renaud.d...@gmail.com>
Date: Friday, December 24, 2021 at 5:11 AM
To: Carbon Dioxide Removal <carbondiox...@googlegroups.com>
Subject: [CDR] Controlled burning of natural environments could help offset our carbon emissions

 

Controlled burning of natural environments could help offset our carbon emissions

Error! Filename not specified.phys.org/news/2021-12-natural-environments-offset-carbon-emissions.html

December 23, 2021

by University of Cambridge

Planting trees and suppressing wildfires do not necessarily maximize the carbon storage of natural ecosystems. A new study has found that prescribed burning can actually lock in or increase carbon in the 

  <big snip>

[Chris Van Arsdale]

(ignoring the biochar discussion for a second)

There's a fundamental issue with burning forests (not so much for savannas/grassland), which is the timescale for net storage. It would have been nice to have that factored into the paper. Forests grow slowly ...  and with changing biospheres, not necessarily with the same level of biomass (the last estimate I saw for the CA Sierras was ~70% regrowth).

If you care about atmospheric CO2 in 2050 (say), the <15% of carbon locked into the soil is likely less than the extra CO2 still residing in the atmosphere. If you only care about 2100, maybe the answer is different, though maybe the extra CO2 and BC from 2Gt-C/y (not a small number!) of wildfires will push us past an inflection point, and the biomass won't come back.

Assuming stability in our biosphere on a 50+ year timescale does not seem like a good basis for policy, there are too many unknowns.

- Chris

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[Tom Goreau]

For tens of thousands of years people have been systematically burning entire landscapes at the end of the dry season, first to manage the wildlife they hunted, later as ash to fertilize the next rainy season grass for cattle.

 

This has turned vast continental seasonally dry areas from high biomass forest to low biomass grassland, maintained by annual burning.

 

Every turn of the annual burning cycle impoverishes the entire ecosystem in volatilized essential elements, especially nitrogen and sulfur.

 

Only about 1% of the carbon becomes soil biochar, but it makes up around half or more of the soil carbon.

 

These soils are rapidly desertified. I’ve seen it myself in parts of northern Senegal that a distant relative of mine first mapped.

 

It would be better to take the useless thornbush scrub left after the cattle have eaten every edible stalk of grass and leaf, turn it all into biochar, add basalt powder and mulch, plant fruit tree seeds and regenerate the site.

 

Then compare to an adjacent plot that is burned down the old fashioned way!

 

This would work to recreate more productive forests even in the Sahel! It is already being done by many groups like Guy Reinaud and Pro Natura: http://www.pronatura.org/en/biochar/

 

It would transform the lives of the Fula herders I worked with, who now herd their cattle, goats, sheep, and camels from desertified thorn bush only to government wells pumping down the fossil groundwater. It can’t last……

 

Full disclosure: I’m a hereditary member of an Arnhemland Aboriginal clan that has been burning the bush for 60,000 years. Those who fail to systematically burn their own lands are regarded as irresponsibly failing to maintain them. It’s a hard, dirty task, but somebody has to do it for the wildlife! Of course, these are light burns because the biomass and soils are so impoverished. It’s difficult now to imagine the tall forests full of giant extinct marsupials that were there before we showed up for dinner and turned all that carbon into CO2!

 

Thomas J. F. Goreau, PhD
President, Global Coral Reef Alliance

Chief Scientist, Blue Regeneration SL
President, Biorock Technology Inc.

Technical Advisor, Blue Guardians Programme, SIDS DOCK

37 Pleasant Street, Cambridge, MA 02139

gor...@globalcoral.org
www.globalcoral.org
Skype: tomgoreau
Tel: (1) 617-864-4226 (leave message)

 

Books:

Geotherapy: Innovative Methods of Soil Fertility Restoration, Carbon Sequestration, and Reversing CO2 Increase

http://www.crcpress.com/product/isbn/9781466595392

 

Innovative Methods of Marine Ecosystem Restoration

http://www.crcpress.com/product/isbn/9781466557734

 

No one can change the past, everybody can change the future

 

It’s much later than we think, especially if we don’t think

 

Those with their heads in the sand will see the light when global warming and sea level rise wash the beach away

 

Geotherapy: Regenerating ecosystem services to reverse climate change

 

[Tom Goreau]

Thanks, Adam!

 

Great paper!

 

Do you have the citation and pdf for the other papers too?

 

I’ll post this to the list, many are interested.

 

Thomas J. F. Goreau, PhD
President, Global Coral Reef Alliance

Chief Scientist, Blue Regeneration SL
President, Biorock Technology Inc.

Technical Advisor, Blue Guardians Programme, SIDS DOCK

37 Pleasant Street, Cambridge, MA 02139

gor...@globalcoral.org
www.globalcoral.org
Skype: tomgoreau
Tel: (1) 617-864-4226 (leave message)

 

Books:

Geotherapy: Innovative Methods of Soil Fertility Restoration, Carbon Sequestration, and Reversing CO2 Increase

http://www.crcpress.com/product/isbn/9781466595392

 

Innovative Methods of Marine Ecosystem Restoration

http://www.crcpress.com/product/isbn/9781466557734

 

No one can change the past, everybody can change the future

 

It’s much later than we think, especially if we don’t think

 

Those with their heads in the sand will see the light when global warming and sea level rise wash the beach away

 

Geotherapy: Regenerating ecosystem services to reverse climate change

 

 

 

From: Adam Pellegrini <ap2...@cam.ac.uk>
Date: Monday, December 27, 2021 at 11:34 AM
To: Tom Goreau <gor...@globalcoral.org>
Subject: Re: [CDR] Controlled burning of natural environments could help offset our carbon emissions

 

Hi Tom—

 

Interesting discussion. Biochar/pyrogenic carbon is such an extensive literature that given the space constraints of nature geoscience, we were restricted to citing some of the core studies/extensive reviews because we wanted to focus on the novel aspects of integrating fire into the persistence framework. Another review appeared in nature geoscience on Dec 3rd that deals specifically with biochar. We have a paper in global change biology that touches on pyrogenic carbon budgets, but these are focused on natural ecosystems without any sort of direct biochar amendments (only indirect amendments as a result of prescribed burns). 

 

Best wishes,

 

Adam

 

Adam Pellegrini

University of Cambridge

---

From: Tom Goreau <gor...@globalcoral.org>
Sent: Monday, December 27, 2021 9:05:29 AM
To: Adam Pellegrini <ap2...@cam.ac.uk>
Subject: FW: [CDR] Controlled burning of natural environments could help offset our carbon emissions

 

Dear Dr. Pellegrini,

 

Could you please send me a pdf of Fire effects on the persistence of soil organic matter and long-term carbon storage?

 

Please see the discussion below:

 

Thanks for your help!

 

Best wishes,

Tom

 

Thomas J. F. Goreau, PhD
President, Global Coral Reef Alliance

Chief Scientist, Blue Regeneration SL
President, Biorock Technology Inc.

Technical Advisor, Blue Guardians Programme, SIDS DOCK

37 Pleasant Street, Cambridge, MA 02139

gor...@globalcoral.org
www.globalcoral.org
Skype: tomgoreau
Tel: (1) 617-864-4226 (leave message)

 

Books:

Geotherapy: Innovative Methods of Soil Fertility Restoration, Carbon Sequestration, and Reversing CO2 Increase

http://www.crcpress.com/product/isbn/9781466595392

 

Innovative Methods of Marine Ecosystem Restoration

http://www.crcpress.com/product/isbn/9781466557734

 

No one can change the past, everybody can change the future

 

It’s much later than we think, especially if we don’t think

 

Those with their heads in the sand will see the light when global warming and sea level rise wash the beach away

 

Geotherapy: Regenerating ecosystem services to reverse climate change

 

[Ronal Larson]

Adam and ccs. (special thanks to Tom G)

1.  For the sake of clarity,  I am skipping a short response from Tom G., and his/my earlier messages as well.  See that message from Tom G received in Mountain time zone at 10:26 AM today.

From: Adam Pellegrini <ap2...@cam.ac.uk>
Date: Monday, December 27, 2021 at 11:34 AM
To: Tom Goreau <gor...@globalcoral.org>
Subject: Re: [CDR] Controlled burning of natural environments could help offset our carbon emissions

 

Hi Tom—

 

Interesting discussion. Biochar/pyrogenic carbon is such an extensive literature that given the space constraints of nature geoscience, we were restricted to citing some of the core studies/extensive reviews

because we wanted to focus on the novel aspects of integrating fire into the persistence framework.

[RWL1:  I thought you did a great job at that.  

Good to hear that our literature is “extensive" (I sometimes still read biochar is not ready). 

 I agree that controlled burns have also been insufficiently used in the past.

Another review appeared in nature geoscience on Dec 3rd that deals specifically with biochar.

[RWL2:   I think I found this - a paper by Johannes Lehmann and 8 more entitled: " Biochar in Climate Change Mitigation."  Google scholar shows a free download at Cornell.

This paper looks very important for this list - as “mitigation” seems to directly equate to CDR.

But I don’t see (yet - I’m just starting to read), a real comparison of biochar and conservation burns.  Could you add a sentence or two on when funders should focus on each approach?  Might biochar’s advances call for it generally replacing conservation burns?   If not yet - what is needed (to get more CDR and forest health)?

Obviously biochar collection will always cost more, but do its soil improvement and CDR advantages yet outweigh the extra costs?

To all:  This Lehmann et al paper looks very well done - many new graphs, I’ve not seen before.

We have a paper in global change biology that touches on pyrogenic carbon budgets, but these are focused on natural ecosystems without any sort of direct biochar amendments (only indirect amendments as a result of prescribed burns). 

[RWL3. Any other wisdom on what biochar activists should be doing now in this (CDR list) issue of improving forest health and minimizing fire damage to forests?  Any other forest soil topics we who are focusing on CDR are missing?

Thanks in advance.

Ron