Forests: Damned if they do, damned if they don't

From the Centre for Ecology & Hydrology

Increased tropical forest growth could release carbon from the soil

This is a view through the undergrowth in tropical forest at the study site in Panama. Credit: Dr. Emma Sayer

A new study shows that as climate change enhances tree growth in tropical forests, the resulting increase in litterfall could stimulate soil micro-organisms leading to a release of stored soil carbon.

The research was led by scientists from the Centre for Ecology & Hydrology and the University of Cambridge, UK. The results are published online today (14 August 2011) in the scientific journal Nature Climate Change.

The researchers used results from a six-year experiment in a rainforest at the Smithsonian Tropical Research Institute in Panama, Central America, to study how increases in litterfall – dead plant material such as leaves, bark and twigs which fall to the ground – might affect carbon storage in the soil. Their results show that extra litterfall triggers an effect called ‘priming’ where fresh carbon from plant litter provides much-needed energy to micro-organisms, which then stimulates the decomposition of carbon stored in the soil.

IMAGE: Measuring CO2 efflux from the soil in subplots where the forest floor has been replaced with litter with a distinct isotopic signature. A wire mesh tent excludes forest litter from…

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Lead author Dr Emma Sayer from the UK’s Centre for Ecology & Hydrology said, “Most estimates of the carbon sequestration capacity of tropical forests are based on measurements of tree growth. Our study demonstrates that interactions between plants and soil can have a massive impact on carbon cycling. Models of climate change must take these feedbacks into account to predict future atmospheric carbon dioxide levels.”

The study concludes that a large proportion of the carbon sequestered by greater tree growth in tropical forests could be lost from the soil. The researchers estimate that a 30% increase in litterfall could release about 0.6 tonnes of carbon per hectare from lowland tropical forest soils each year. This amount of carbon is greater than estimates of the climate-induced increase in forest biomass carbon in Amazonia over recent decades. Given the vast land surface area covered by tropical forests and the large amount of carbon stored in the soil, this could affect the global carbon balance.

IMAGE: This is leaf litter around the buttress roots of a tropical tree at the study site in Panama.

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Tropical forests play an essential role in regulating the global carbon balance. Human activities have caused carbon dioxide levels to rise but it was thought that trees would respond to this by increasing their growth and taking up larger amounts of carbon. However, enhanced tree growth leads to more dead plant matter, especially leaf litter, returning to the forest floor and it is unclear what effect this has on the carbon cycle.

Dr Sayer added, “Soils are thought to be a long-term store for carbon but we have shown that these stores could be diminished if elevated carbon dioxide levels and nitrogen deposition boost plant growth.”

Co-author Dr Edmund Tanner, from the University of Cambridge, said, “This priming effect essentially means that older, relatively stable soil carbon is being replaced by fresh carbon from dead plant matter, which is easily decomposed. We still don’t know what consequences this will have for carbon cycling in the long term.”

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wayne Job

A rather circular argument about nothing with no consequences, are they trying to prove that nature is trying to destroy us!!! WTF CO2 will and has been increasing biomass world wide big time. The world has been running on almost empty for so long and when the world starts to bloom they have a pink fit. What do these greenies really want?

David Schofield

Let me get this straight, the carbon offset I might pay for my flight goes towards growing trees, which releases more carbon? It has taken them 6 years to work out that if you have more/bigger trees you have more leaf litter??? if one of my undergrads had written this I wouldn’t be impressed.
This is turning into a joke.

John Trigge

Models of climate change must take these feedbacks into account to predict future atmospheric carbon dioxide levels.
Maybe the models should take this into account to determine the current carbon dioxide levels that are not attributed to mankind.
“Things are not worse than we thought.”

Andrew Harding

Does common sense go out of the window when any “scientific” research involving carbon dioxide takes place? Or can I be truly cynical and ask if this research is an attempt to prove that planting more forests cannot undo the bad things that mankind has done to the planet, therefore we need to be taxed more to prevent us flying and using our cars?

John Marshall

The Carbon Cycle is a vital recycling process and we are finding out more and more about it. As to this research proving a possible extra climate driver or being a ‘danger’ or whatever alarmist claptrap that will now appear I say ‘So What’.
This process has been in operation for billions of years and recent learning about a small part of it does not change anything. Especially the reality that carbon dioxide does NOT drive climate.
It does drive plant growth and as far as plants are concerned the more the better.

Richard Abbott

The bleeding system has worked for billions of years. Now Johny come lately man briefly enters onto the scene postulating this way, then that way. Give me a break! I will settle for Pythagoras theorem where the “sum of the squares……”

Ian E

The science is settled.
The science is settled.
The science is settled.
What part of that do these researchers not understand?

Richard Abbott

“Dr Sayer added, “Soils are thought to be a long-term store for carbon but we have shown that these stores could be diminished if elevated carbon dioxide levels and nitrogen deposition boost plant growth.””
So – plants remove CO2 from the atmosphere, more plants do not. Is this the vegetation/CO2 tipping point that climate catastrophists have been waiting for?
This kind of statement goes beyond simple error into Monty Python territory. It would be funny if they weren’t spending our money on this astonishing nonsense.

WAM

Once the carbon is released from the soil, what happens next? There is a LOT of green leaves above… Of course, at nights there will be net CO2 release to the atmosphere, but during the daytime? So release of CO2 from the soil is one thing, and what happens next is another thing.
I hope no one advises to cut as much of rain forrest as possible (as a result of this research) 🙂

CodeTech

So, um… chop down the rainforests?
Seems to me this is beneficial to a forest… a natural source of food just wafting up from the ground. Maybe it’s the way they’re supposed to be.
Man, I’m sure glad I’m not one of those people that panics every time I hear about another source, or potential source, of Carbon Dioxide… they’re finding it everywhere these days. Next it will be found outgassing from Coke and Mountain Dew…

That’s just plain funny. They’ve gone and created their own custom-made ‘tipping point’!
1. Climate change causes trees to grow (they don’t reveal how they can tell this).
2. More trees=more leaf litter=more humic acid=more ‘carbon’. (it’s not enough that the poor element is maligned by terminology misuse)
3. More ‘carbon’ gets released, causing more climate change. Brother.
When will it all just shut up and go away?

No such thing as a free lunch. Soils known to be rich in available organic carbon are usually productive. Part of this is because they consume soil carbon much as described and possibly by other cycles. Part is because the carbon helps increase the cation exchange capacity of the soil (its ability to hold nutrients before they are flushed down the creek).
Any competent geochemist will tell you that organic carbon does not accumulate in soils with time. It plateaus out at about 2% by weight, with higher values in the rare terra preta and lower values in desert sands. This is because we are dealing with a dynamic system with a number of competing reactions whose individual rates can vary, in ways that have not been measured and identified so often.
The thought that one can sequester carbon in soils or trees is true only so long as the trees are maintained at or near maximum carbon yield weight per hectare of tree and when other soil nutrients are not severely limiting. You cannot harvest forest and grow new trees in a ‘sustainable’ way because each tree you take from the property has a weight of carbon, phosphorus, potassium, calcium, trace elements and so on. These become depleted unless artificial fertiliser (usually) or mulch (so old fashioned) is applied.
So stay well clear of snake oil salesmen asking you to invest in tree plantations for carbon credits. Such schemes will usually carry the seeds of their destruction, but have the advantage that they are likely to outlast the salesman, who would make a rounded fertilizer by himself. (True – 100 years ago, boatloads of mummified cats were shipped from Egypt to England for fertilizer.)

FergalR

1. Dump leaves under a plastic tent for a couple of years.
2. ???
3. Profit!
Hook a dynamo up to Galileo’s corpse, we’ll have all the energy we need.

Luther Wu

…”it is unclear what effect this has on the carbon cycle.
:…”we have shown that these stores could be diminished if elevated carbon dioxide levels and nitrogen deposition boost plant growth.”
We still don’t know what consequences this will have for carbon cycling in the long term.”
Obviously, more long- term grant money is needed for further study.

Dr. Dave

This is the start of the “more CO2 is bad” even if it doesn’t cause CAGW meme.

Richard111

Gosh! Whatever next? Question: CO2 is a massy molecule. There is not a lot of wind (I am led to believe) inside rain forests. Will this newly released CO2 rise above the canopy to become “well mixed” at levels being measured on the forest floor?

“We still don’t know what consequences this will have for carbon cycling in the long term”
Try “None”, leaves have been falling off trees ever since trees were invented! Nature seems to have managed OK thus far without a six year study.

jason

So, replanting the amazon is a BAD thing.

So, let’s get this straight…. we’re told that the biosphere absorbs about half of the extra co2 we sinning humans have put into the atmosphere from burning fossil fuels. But this is now found to be impossible because although measurement shows biomass has increased 7% in 30 years, the additional leaf litter causes bugs in soil to release more co2 than the additional biomass absorbs?
Doesn’t look like settled science to me.

Curiousgeorge

So this would have some implications for the backyard mulch pile, correct? I’m so confused. Should I burn my annual leaf fall? Maybe I should burn my tree’s to prevent leaf litter, and pave over everything. What to do, what to do.

Alan the Brit

“the resulting increase in litterfall could stimulate soil micro-organisms leading to a release of stored soil carbon.” Or, it could not!
“dead plant material such as leaves, bark and twigs which fall to the ground – might affect carbon storage in the soil.” Or, it might not!
“Our study demonstrates that interactions between plants and soil can have a massive impact on carbon cycling. Models of climate change must take these feedbacks into account to predict future atmospheric carbon dioxide levels.” Or, it can not! Oh & what’s with the “prediction”, Mystic Meg, or should it be Septic Peg??
“Human activities have caused carbon dioxide levels to rise but it was thought that trees would respond to this by increasing their growth and taking up larger amounts of carbon”. Have they? By how much? What percentage of the total atmospheric Carbon Dioxide is attributable to them? Perhaps the original “was thought”, was wrong!
Dr Sayer added, “Soils are thought to be a long-term store for carbon but we have shown that these stores could be diminished if elevated carbon dioxide levels and nitrogen deposition boost plant growth.” Was that “thought” right? Could, if?
“We still don’t know what consequences this will have for carbon cycling in the long term.” You don’t know? Still? After 20 years & billions of dollars & pounds & every other currency known to humanity being flung at it? More improtantly, it is obvious to anyone that this priming malarky has been going on for millions of years in none ice-bound areas & interglacials 🙂
Cambridge is not a million miles from Norwich (UEA), you know (about 56 miles WSW as the proverbial crow flies!) & Norfolk borders Cambridgeshire!!! They’re practically kissin’ cousins, geographically speaking!!!!! Perhaps some of the bizarre thinking going on at UEA has percolated through the ether to Cambridge, who knows?

Ian Forman

“Human activities have caused carbon dioxide levels to rise” is one of those throwaway remarks that might persuade some to believe it is substantial and produces harmful effects; but we here all know different: carbon dioxide is harmless, nay, beneficial, and doesn’t to any real extent cause warming. Unfortunately, until the sceptic side finds someone able to say so in a form that has some force and gets noticed, we shall go on hearing the same old same old for years and years.

David, UK

A small plant or a huge tree – it’s all the same principle: they are simply part of a carbon CYCLE. What drops to the ground from the trees is only what came out of the ground (and the air) in the first place. And don’t even get me started on microbes. Or termites. Or cows. It’s a CYCLE, STUPID!

Gary Mount

The lesser amount of stored carbon in the soil is counterbalanced by the greater amount of carbon stored in the greater number of micro-organisms.
Is it proper to call greater CO2 levels, “climate change”?

Neil Jones

It’s a conspiracy I tell you! This is how the plants are take over the planet
.

@Bromley the Kurd: It will only shut up and go away when the money goes away. In some countries that seems to be happening already, but not in the US.
This graph is an eye-opener. Note that “Republican” Bush raised funding, then “Democrat” Obama raised it again, but the 2009 Cornucopia For Bankers And Corporate Welfare Queens is the biggest chunk of all. A real hockey-stick.
http://ockhamsbungalow.com/blog27/funding-graph.jpg
Graph is clipped from this PDF document:
http://www.cbo.gov/doc.cfm?index=11224&type=1

gas

After careful reflection of the implications of all this and a deep prognostic contemplation I feel that the only reasonable response to this is…………………….HAHAHAHAHAHAHAHHAHAHAHAHAHAHAHAHAHAHAHA………………phew….that’s better…..going for a drive in my beautiful 6litre V8 now…..runs on 85% ethanol so no worries…

Espen

Geoff Sherrington says:
August 15, 2011 at 3:40 am

Any competent geochemist will tell you that organic carbon does not accumulate in soils with time.

I thought this was different in boreal forests – they’ve been slowly accumulating organic soil since the last glaciation and still do.

Louis Hooffstetter

This is classic! Forests obviously take in CO2 as they grow, and then release some of it as dead and discarded plant material decays. The only question is: How much more CO2 is sequestered than released?
Six years of study, and the authors have no clue.
A complete waste of time and research money.
Climate science at its best.

Crito

Are Humans the problem? or is it just the less equal humans who do not understand the threat?

Hmm, the models will need fixing – time to start modelling leaves, soil and decomposition… get the research grants in….
Just goes to prove to me that under a complex system is always more complexity. Keep digging..

Cassandra King

So this is what science has degenerated into? Pseudo science mumbo jumbo, half assed and half baked and half understood with the author of this putrid garbage placing the essential begging request at the end. This I suppose is the end result of two decades of massive funding from centralised funding bodies pouring monies into any group involved with the CAGW fraud and I call it a fraud because that is essentially what it is.

lol, oh my…….so, they would lead us to believe more trees means more CO2…… …. I’m not sure they have the basics of the concept of “carbon based life forms” down just yet.
There’s plenty more to say about this waste of time, space and energy, but I’ll just point out that this too is peer reviewed and written by our experts. —– with doctorates and everything….. 😐

phizzics

Weren’t there a few studies that showed that increased CO2 would stunt the growth of trees?
Apparently the CAGW bunch have decided that there was no way to support that bit of nonsense, so they’ve moved on to calling bigger, healthier trees a threat to the rest of us. The good news is that my chainsaw is now “carbon neutral”.

Crispin in Waterloo

In the heart of the Amazonian jungle, there are nearly no nutrients remaining in the soil compared with, say, healthy grasslands – it is all in the tree trunks and canopy. Trees such as the Jacaranda, which is native to that area, pump huge amounts of water out of the ground pulling up any available nutrients then drop quite a lot of water onto the ground over their roots with what appear to be digesting enzymes and sugars (which feed rock-digesting bacteria, see the work of Dr AD Karve) in them. Don’t park your car under one. This helps the Jacaranda gain more benefit than its neighbour from the available resource.
The paper shows that as the forest grows (in a tropical setting) the carbon gradually shifts above the ground by natural processes. When ‘fully developed’ there is less carbon in the ground than before and a lot more in the living biomass above it.
A similar process will take place when the permafrost melts. There is very little growing above the ground now and lots of carbon below the ground deposited the last time it was warm. The ratio of above:below will evolve.
There is no doubt that in both cases the net effect will be to have more total carbon in the living system, which carbon is pulled from the air.

Andrew Harding

Am I paranoid or does anyone else on WUWT think that there is an orchestration of scientific “research” to promote the concept of AGW and very little, if any research is independent? There are a couple of reasons for my thoughts on this:
1) What warped train of thought would lead a team to pump isotopes of carbon into the ground and measure the amount of CO2 released?
2) There are absolutely no research results stating that AGW is not occurring. Statistically there must be, therefore those results have not been published.
3) All research must be peer reviewed, the peers involved in AGW are more like a clique than peers.
I have said several times that the AGW bandwagon is like the tobacco crusade, once the smoking ban was in place in UK the number of papers published finding more health problems linked to tobacco has dropped substantially. The other similarity is that as time goes on the claims of each crusade get more and more outlandish ( I was told in all seriousness by a health professional, that if I picked my baby son up within in hour of smoking a cigarette, the nicotine in my breath could cause cot death. I am pleased to report that I gave up when he was 12 and he is a healthy 16 year old now).
After tobacco came alcohol, in UK we have endless “experts” telling us that the death toll will reach biblical proportions unless everyone stops drinking.
So my next question is that after we are all reduced to living in feudal economies, with no power when the wind stops blowing and no means of transport, what is the next global calamity heading our way that needs billions spent in research to avert it.

Stacey

It is clear that this study shows that they can’t see the wood for the trees?
Hopefully when the error of their ways is pointed out they will turn over a new leaf:-)

Bruce Cobb

Uh-oh, this could negatively impact the Reducing Emissions from Deforestation and Forest Degradation (REDD) carbon scam program.
Further carbon “studies” will be necessary to correct this. Balancing the needs of both the carbon “scientists” and the countries who might be beneficiaries of “carbon science” can be difficult.

nofreewind

So what this means is that the entire Carbon Cycle “theory” is far from fact!
http://www.nofreewind.com/2009/06/man-made-and-natural-co2-in-atmosphere.html

At least you did not question their beleaf system, Stacey…

Latitude

well…..you can’t argue with it
might, could, can, if…….
and the take home…..
“We still don’t know what consequences this will have for carbon cycling in the long term.”
…..but they met their requirements, and published

“…… it is unclear what effect this has on the carbon cycle”
“Models of climate change must take these feedbacks into account to predict future atmospheric carbon dioxide levels”
So how do the modellers build in these “unclear” effects or feedbacks?

Keith

I could do with a nice break somewhere warm and relaxing I’m thinking of conducting research into the impact of anthroprogenic climate change on the size of sand grains on tropical beaches. Obviously this would take a few months of intensive study at a number of different locations, and would be just as beneficial to the sum of human knowledge and welfare as this nonsense.

Neo

Then obviously, forrests can’t possibly be added to the books as a “carbon sink.”
I wonder if Brazil knows.

crosspatch

Given the vast land surface area covered by tropical forests and the large amount of carbon stored in the soil, this could affect the global carbon balance.

And why, exactly, does anyone really care about “the global carbon balance”? Thousands more dollars flushed down the toilet for no reason.

Foxgoose

To make perfect sense of all this vacuous, vacillating nonsense, just remember that the whole green enterprise is just a vast, worldwide job creation scheme for second-rate scientists .
Just think of your tax contribution to it as charity for the otherwise unemployable.
Does that make you feel better?
No – me neither.

Steve Keohane

So what happens in the forests from say 30° away from the equator. I know here in Colorado, trees that burned to a stump 100-150 years ago are still sitting there, as well as a lot of charcoal, sequestering a lot of CO2. This implies a great deal of forest area has it’s litter simply build up for a long time with minimal decay.

Who knew that Joni Mitchel would prove to be a prophet….
“Pave Paradise — Put up a Parking Lot”…. and so ye shall save the Earth.
Wonderful. Now I should buy shares in logging and paving companies. I am going to get rich while saving the environment. (I plan to buy a home next to Al Gore …with all the prophets… er profits.)
http://jonimitchell.com/music/song.cfm?id=208

Gary Pearse

Wow the desperation because of cooling has a last-chance fervor. They apparently have had no compuction about discarding the 1st law of thermodynamics and now they are taking a run at the law of conservation of mass. Mass balance good doctors, mass balance!

Since CO2 is heavier than nitrogen and oxygen, and the leaf litter and other organic cast offs from the trees are emitting so much CO2, and there is really little air movement in the tropical rainforests to dissipate the CO2, aren’t these “scientists” afraid they may be suffocated by the CO2? You would at least think the smaller ground dwelling insects, reptiles and mammals would be suffocating. (I’m being sarcastic here.)