Global Warming May Affect the Capacity of Trees to Store Carbon, MBL Study Finds
WOODS HOLE, MA—One helpful action anyone can take in response to global warming is to plant trees and preserve forests. Trees and plants capture carbon dioxide during photosynthesis, thereby removing the most abundant greenhouse gas from the atmosphere and storing some of it in their woody tissue.
Yet global warming may affect the capacity of trees to store carbon by altering forest nitrogen cycling, concludes a study led by Jerry Melillo of the Marine Biological Laboratory (MBL), published this week in Proceedings of the National Academy of Sciences.
The paper summarizes the results of a 7-year study at Harvard Forest in central Massachusetts, in which a section of the forest (about one-quarter of an acre) was artificially warmed about 9oF above ambient, to simulate the amount of climate warming that might be observed by the end of the century without aggressive actions to control greenhouse gas emissions from fossil-fuel burning and deforestation.
The study confirmed, as others have, that a warmer climate causes more rapid decomposition of the organic matter in soil, leading to an increase in carbon dioxide being released to the atmosphere.
But the study also showed, for the first time in a field experiment, that warmer temperatures stimulate the gain of carbon stored in trees as woody tissue, partially offsetting the soil carbon loss to the atmosphere. The carbon gains in trees, the scientists found, is due to more nitrogen being made available to the trees with warmer soil.
“Tree growth in many of the forests in the United States is limited by the lack of nitrogen,” Melillo says. “We found that warming causes nitrogen compounds locked up in soil organic matter to be released as inorganic forms of nitrogen such as ammonium, a common form of nitrogen found in garden fertilizer. When trees take up this inorganic nitrogen, they grow faster and store more carbon.”
Melillo says that the biological processes that link soil warming, increased soil organic matter decay, increased nitrogen availability to trees, and increased tree growth will likely operate together in many temperate and boreal forests—forests found in North America, Europe, Eurasia and much of the developed world. Tree growth in tropical forests is often limited by factors other than nitrogen, so lessons from this new study are not widely relevant in the tropics.
While Melillo thinks that the carbon-nitrogen interactions he is studying at Harvard Forest will help us to make predictions of carbon storage in forest over the coming decades, he adds that “the carbon balance of forest ecosystems in a changing climate will also depend on other factors that will change over the century, such as water availability, the effects of increased temperature on both plant photosynthesis and aboveground plant respiration, and the atmospheric concentration of carbon dioxide.”
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The Marine Biological Laboratory (MBL) is dedicated to scientific discovery and improving the human condition through research and education in biology, biomedicine, and environmental science. Founded in 1888 in Woods Hole, Massachusetts, the MBL is an independent, nonprofit corporation.
Citation:
Melillo, J., Butler, S., Johnson, J., Mohan, J., Steudler, P., Lux, H., Burrows, E., Bowles, F., Smith, R., Scott, L., Vario, C., Hill, T., Burton, A., Zhouj, Y, and Tang, J. (2011) Soil warming, carbon–nitrogen interactions, and forest carbon budgets. PNAS: Early Edition May 23, 2011, doi: 10.1073/pnas. 1018189108
If real, this increase in CO2 sequesteration with higher temps should provide a very small mitigation of the coming global cooling. Struggling plants will release some carbon into the atmosphere, somewhat offsetting the absorption of CO2 to the oceans, so that CO2’s small greenhouse effect will be a tiny bit larger than it otherwise would be. Yay.
Carbon dioxide is the most abundant greenhouse gas?
9 deg F (5 deg C) is a big ask in the next 90 years – esp. since the temps seem to have flat-lined.
I thought the reasonable estimates were of the order 2 deg C?
But nice to know my sub-tropical Native Forestry patch in NZ will do its bit though – shame the local Council allowed all my neighbours to raze all theirs to build 2nd houses. Now only me and my next-door neighbour have stands of native timber (one or two trees probably well over 500 years old)
Andy
“You never change just one thing.”
There won’t be any global warming,
but a much greater stimulus to plants
will be higher CO2.
The climate models of plant response to higher CO2
use only experiments with plants that grew up unaugmented
and then were given high CO2.
Recent results are
that generations of plants growing in high CO2
will be selecgted to respond even more strongly than today’s.
The scientifically expected outcome is that uptake of our CO2
will accelerate from the current 2/3rd,
due to the higher ppm, until all our emissions are absorbed
and CO2 leveling out
without us having to do anything at all.
Where could I start a betting pool on when and how high
the CO2 rise stops?
Let’s remember that we’re unlikely to ever get oil production
over 100 Million BPD, nor will coal go substantially higher
before it also plateaus.
The only multiplier-type growth left is in fracking natural gas.
Even so, between the global growth of vegetation cover and ocean cooling from the coming Little Ice Age, I look for a CO2 plateau of 450 ppm in 50 years, falling thereafter, along with sea level (if still around, Obama will of course take credit for that, while saying that all those cold decades will have been due to global warming).
Just about the dumbest thing I have ever heard in my life…did he really say that they ‘took a chunk of forest in the middle of an expanse of forest and ””warmed it”’ by… this 9 degrees F, not 10 or eight but 9…and then studied how the trees reacted?
I would have loved to have seen that!
Wouldn’t that have been something?
They must have enclosed it in some way in order to make this harebrained 9 degrees claim…so what happened with Transpiration as the natural forest breezes were eliminated? Trees don’t like being put in a greenhouse and being heated up…oh and just out of zany curiosity…did they lay this on the poor trees without warning…one year normal, the next Bam! or did they phase it in over a period of years?
The mind boggles at what passes for science these days.
I’ll bet these ‘scientists’ were the kind of kids whose Moms pinned up their ghastly infantile scrawls with pride telling them how wonderful and clever they were…and they believed it.
Who are the people who put up money to pay for such ‘experiments’ can I have their address…? I’ve got an aquaintance who believes that if you stick a feather in the ground it could grow into a hen…do you think he might be up for a reasearch grant?
It’s just so….tsk….I can’t stop myself…this is like shooting fish in a barrel.
So in this ‘controlled environment’ was the atmospheric composition kept the same as the external atmosphere, or were the gases that the earth would naturally release if warmed, captured and retained?
Did they heat the soil?
Was the tree body and canopy enclosed at +9F while it’s root system was still drawing water and nutrients at the natural ambient temp…or did they ””warm”’ the subsoil too…I have been told that the roots of a tree often mirror the tree itself in size and shape…
I could exhaust myself with this one it’s just so…wrong.
But finally…finally…I have to come clean and admit that for a living, I try to control temperatures in spaces…and I promise you, you can easily get three different temperature readings INSIDE YOUR FRIDGE…but I take my hat off to these cats, these dudes…they have stabilized a chunk of forest at +9F.
It’s not April Fools day is it?
” for the first time in a field experiment, that warmer temperatures stimulate the gain of carbon stored in trees as woody tissue, ”
Didn’t dendrochronologists already know this?!
I’m probably being stupid but if tree rings are supposedly wider because of warmth then there must be more carbon sequestered that year in woody tissue. Isn’t there a scientific consensus on that?
I think Roger Knights and I are of a similar opinion…he’s just more concise.
“….thereby removing the most abundant greenhouse gas from the atmosphere…”
In my opinion that would be water wapour.
Can you imagine the off setting carbon sequestration of those trees if they had also simulated the 2 or 3 thousand parts per million of CO2 that supposedly would cause +5C? Over the next….check IPCC eye chart, extrapolate…. 20 centuries? But the really funny part is this:
They’ve just shown that even if AGW were true…its beneficial to life on earth from the microbial to the most majestic trees, and everything in between. (Don’t tell the AGW scientists, it will only prompt them to start studying termites and beavers to show they are more active at warm temperatures and hence will limit the ability of trees to sequester carbon)
There is on average 38 times as much H2O vapor in the atmosphere as there is CO2, assuming RH of 50% globally. What will really put the whammy on agriculture will be the CO2 and H20 locked up by advancing Ice Sheets, should another Ice Age begin taking out arable lands.
A few camping trips should remedy that ! 🙂
Anthony,
The paper released April 12, 2011, titled Soil Warming,
carbon-nitrogen interactions, and forest carbon budgets:
http://www.mbl.edu/news/press_releases/pdf/pnas11_melillo_soilwarm.pdf
goes into superior details on the “warm” test area having an appreciable
tree root growth rate, earlier budding, and an increase in measurable above- and
below ground woody boimass.
– – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – – –
So, is this additional uptake in carbon phenomenon a factor in Ken Briffa’s
difficulties in using recent (post 1960’s) tree rings as a proxy for global temperature
increases ?
Does it confirm or comport with the concerns he expressed in 1999 and were
later almost included in the IPCC’s 2001 report ?.
See:
http://www.artdiamondblog.com/archives/2010/03/_the_group_expr.html
There are no Briffa, et al. studies aren’t among the 51 citations at the end of the paper.
@ur momisugly Peter,
hmm, that seems a very incorrect statement, doesn’t it.
When they raised the temperature of the soil it activated the soil fungi to consume more raw organic matter giving back the nitrogen and phosphorus that had been stored in the un decayed wood/mulch/organic matter on the ground. This is well know and from moving from Kansas to Arizona I see right away the lack of accumulated organic matter in these warmer soils, the same as tropical forest soils where the decay rate from heat and moisture prevents the build up of the humus content that makes mid-latitude soils so fertile.
My question was did they continue the study long enough to find the slope of the drop off of the “increased fertility” as the stored humus was removed faster than it was returned as new fallen leaf litter and small twigs and bird poop, feathers, nest refuse.
My guess that after about 3 to 5 years the plateau of stabilization of input to output at the new soil temperature would be reached at some base level again, just like the atmosphere is doing, going back to close to the average again after a solar activity push, that is over now.
I vaguely recall that with more co2 in the atmosphere vegetation would suffer from nitrogen depletion. Now I’m told a warmer soild would release more nitrogen. You see what happens when you stop playing reduce your Nintendo games and actually perform field experiments.
Is this Gaia at work? Is this one of the reasons why Warmists predictions keep falling flat? Is this one of the reasons why the biosphere, during the warming phase, was greening? I don’t have a clue.
Here is a vegetation study published in 2003.
Nature always has surprises up its sleeve. ;O)
Did they also raise the CO₂ by two doublings to simulate the “cause” of the temperature rise? I calculate 380*2^2, or 1520ppm. If not, their experiment is a massive fail.
cheers,
gary
Plants love CO2 it provides the basic building blocks for cellular growth. Increased atmospheric CO2 also reduces the plant’s requirement of water. Getting more crops using less water is a great bonus.
The theory of GHG’s is not a valid theory!
OK, I read the paper; no CO₂ increase to match the increased temperature. I don’t see much value to the experiment, other than to show that warmer conditions will lengthen the growing season and generally improve plant growth.
Now I wonder who could have written this story. Well, yes… by someone who knows not the least bit about atmospheres to make such a basic mistake. OTOH, we do need to preserve trees and forests, I agree there, but because of other reasons besides CO2. CO2’s our least worry if a worry at all.
Firstly some mush head has converted 5C to 9F – isn’t celcius understood in scientific circles everywhere?
Secondly, they heated the to few cms of soil to ambient+5C (heater wire buried at 10cms)
Thirdly when you have accelerated the conversion of biomass in the soil to “ammonium” ??? don’t you eventually run out of biomass. ( or was leaflitter building year-on-year without the heating.
Fourthly not heating the most important solar converters (leaves) to the same temperature means that this is a weird experiment not mimicing any thing that could be caused by global warming.
Fifthly no CO2 increase as others have said!
It took a research paper to tell the world what anyone can see for themselves?
Trees and plants between the Tropics of Capricorn and Cancer grow naturally at temperatures of 30-40 degrees C which is a bit more than the 9 degrees C more than the temperatures in the temperate zones (tropic of Cancer to Arctic circle and tropic of Capricorn to Antarctic circle). Look at how well they grow! Look at how big they grow! Look at the tropical speciation (species diversity). Look at the forest density (does the word JUNGLE conjure any images?).
The planet is just coming out of the refrigerator and the panic is on to send it back in … sheesh.
So, essentially, they proved why jungles around the equator are better climates for trees to grow in and why we in the northern hemisphere tend to use green houses.
Uhm, why didn’t I think to get funds for that? 0_O
What’s next? To prove that fish will be more abundant without fishermen?
I don’t get why they had to waste all this time and money artificially heating a particular spot. Surely there’s enough natural temperature variability around the world to be able to look at how trees respond across a broad range of temperatures? Did the MBL study really tell us anything that couldn’t have been determined more easily this other way?