Warmer temperatures stimulate the gain of carbon stored in trees

Jerry Melillo

Harvard Forest in Petersham, Massachusetts, a National Science Foundation Long-Term Ecological Research site. Photo by David R. Foster.

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.”

—###—

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
PDF of paper

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79 thoughts on “Warmer temperatures stimulate the gain of carbon stored in trees

  1. 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.

  2. 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

  3. 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).

  4. 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?

  5. ” 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?

  6. I think Roger Knights and I are of a similar opinion…he’s just more concise.

  7. “….thereby removing the most abundant greenhouse gas from the atmosphere…”

    In my opinion that would be water wapour.

  8. 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)

  9. 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.

  10. “Tree growth in many of the forests in the United States is limited by the lack of nitrogen,”

    A few camping trips should remedy that ! :)

  11. 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.

  12. 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.

  13. The carbon gains in trees, the scientists found, is due to more nitrogen being made available to the trees with warmer soil.

    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.

  14. 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.

    Models predict that global warming may increase aridity in water-limited ecosystems by accelerating evapotranspiration. We show that interactions between warming and the dominant biota in a grassland ecosystem produced the reverse effect.

    http://dx.doi.org/10.1073/pnas.1732012100

    Nature always has surprises up its sleeve. ;O)

  15. 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

  16. 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!

  17. 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.

  18. 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.

    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.

  19. 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!

  20. 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.

  21. 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?

  22. 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?

  23. “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.”

    So they heated up the ground, which caused more rapid decay, releasing extra nutrients into the soil, which caused more rapid tree growth… byproduct is needing more CO2 for the extra metabolism. Fertilize the plant… get better growth. Who ever would have guessed?

  24. So plants generally grows faster and fatter in warmer conditions – gee, who wooda thunk it? How much did it cost us to find this out?

  25. sophocles says: It took a research paper to tell the world what anyone can see for themselves?

    Well … they had to write a paper or they wouldn’t have been able to justify the money they spent on themselves.

  26. sophocles says:
    May 28, 2011 at 3:50 am

    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?).

    How well do those trees grow after several months of below freezing temperatures?

    A tropical forest would be an awful choice for a control sample to compare with a temperate forest.

  27. charles nelson says:
    May 28, 2011 at 12:56 am

    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?

    You need to read more, I’ve several dumber things in my life. I don’t see the word “chunk” used anywhere here or in the paper. (My father explained the concent of adiabtic expansion starting with “Take a handful of air” – chunk of forest is much easier to envision.) The 9°F comes from the press release, presumably written for colloquial American news reporters. Obviously they really used the rounder 5°C. The paper refers to “The projected warming of between 1.1 °C and 6.4 °C over the next 100 y (11)” and (11) is “Alley R, et al. (2007) Climate Change 2007: The Physical Scientific Basis, Summary for Policymakers (Cambridge University Press, New York).”

    If I were designing such an experiment, I’d take a value close to the high end of projections du jour to give the strongest signal. Note that the experiment began in May 2003 (and construction in 2001). This was before the PDO switched to a negative mode and global warming began to wane. If they were designing the experiment now they might have gone for a lower temperature delta.

    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 [sic] grant?

    Instead of spreading your joy here, perhaps you should talk to the NSF and DoE, they funded the study.

  28. We learned this in my Forestry classes in the late 70’s. But I guess that was when we were heading for an ice age and research funding was scarce and had to be justified.

  29. It is ironic that current research and the paleo record unequivocally supports the statement that the biosphere expands and is more efficient due to higher atmospheric CO2,as the so called green groups advocate carbon caps and carbon sequestration. The problem appears to be an inability to think independently and the green leaches such as those who profit from “wind farms” and “carbon trading” and “green consulting”.

    Benefits due to Increasing CO2
    The finding that increasing CO2 levels has caused a 50% increase in Aspen growth is not a surprise. Atmospheric CO2 is only 0.03%. Plants are 90% carbon and water. If the planet warms the models and paleoclimatic record show there will be an increase in precipitation. The paleoclimatic record indicates most of the warming is at higher latitudes where growth is stunted due to the short period of frost free days.

    Higher atmospheric CO2 enables plants to reduce the number of stomata on their leaves thereby reduce lose of water. C3 Plants currently lose roughly 50% of the water they absorb. Plants optimize the number of stomata on their leaves as CO2 levels rise up. The optimum level of CO2 for plants is around 1500 ppm to 2000 ppm.

    CO2 levels are currently the lowest in 200 Million years.

    Commercial greenhouses inject CO2 to increase yield and reduce growing times.

    http://www.timesonline.co.uk/tol/news/environment/article6036529.ece

    “There is no doubt that the enrichment of the air with CO2 is increasing plant growth rates in many areas,” said Professor Martin Parry, head of plant science at Rothamsted Research, Britain’s leading crop institute.

    TREES and plants are growing bigger and faster in response to the billions of tons of carbon dioxide released into the atmosphere by humans, scientists have found.
    Researchers in Germany recently discovered that wheat grown in similar conditions would produce up to 16% more grain.

    http://www.sciencedaily.com/videos/2007/0603-can_carbon_dioxide_be_a_good_thing.htm

    http://www.sciencedaily.com/releases/2009/12/091204092445.htm

    Greenhouse Gas Carbon Dioxide Ramps Up Aspen Growth

    The study, by scientists from the University of Wisconsin-Madison and the University of Minnesota at Morris (UMM) and published December 4 in the journal Global Change Biology, shows that elevated levels of atmospheric carbon dioxide during the past 50 years have boosted aspen growth rates by an astonishing 50 percent.

    Previously, scientists have shown that plants and trees in growth chambers respond to levels of carbon dioxide well above levels in the atmosphere. The new study is the first to show that aspen in their native forest environments are already growing at accelerated rates due to rising ambient levels of carbon dioxide in the atmosphere.

    http://www.advancegreenhouses.com/use_of_co2_in_a_greenhouse.htm

    Carbon dioxide is one of the essential ingredients in green plant growth and is a primary environmental factor in greenhouses. CO2 enrichment at 2, 3 or four times natural concentration will cause plants to grow faster and improve plant will quality.

    Carbon dioxide is an odorless gas and a minor constituent in the air we breathe. It comprises only .03% [ 300 parts per million, or PPM] of the atmosphere, but is virtually important to all life on this planet! Plants are made up of about 90% carbon and water with other elements like nitrogen calcium, magnesium, potassium, phosphorus and trace elements making up only a small percentage. Almost all the carbon in plants comes from this minor 300 ppm of carbon dioxide in the air.

    http://www.sciencedaily.com/releases/2003/05/030509084556.htm

    Greenhouse Gas Might Green Up The Desert; Weizmann Institute Study Suggests That Rising Carbon Dioxide Levels Might Cause Forests To Spread Into Dry Environments

    The Weizmann team found, to its surprise, that the Yatir forest is a substantial “sink” (CO2-absorbing site): its absorbing efficiency is similar to that of many of its counterparts in more fertile lands. These results were unexpected since forests in dry regions are considered to develop very slowly, if at all, and thus are not expected to soak up much carbon dioxide (the more rapidly the forest develops the more carbon dioxide it needs, since carbon dioxide drives the production of sugars). However, the Yatir forest is growing at a relatively quick pace, and is even expanding further into the desert.

    Plants need carbon dioxide for photosynthesis, which leads to the production of sugars. But to obtain it, they must open pores in their leaves and consequently lose large quantities of water to evaporation. The plant must decide which it needs more: water or carbon dioxide. Yakir suggests that the 30 percent increase of atmospheric carbon dioxide since the start of the industrial revolution eases the plant’s dilemma. Under such conditions, the plant doesn’t have to fully open the pores for carbon dioxide to seep in – a relatively small opening is sufficient. Consequently, less water escapes the plant’s pores. This efficient water preservation technique keeps moisture in the ground, allowing forests to grow in areas that previously were too dry.

    http://news.nationalgeographic.com/news/2009/07/090731-green-sahara.html

    The green shoots of recovery are showing up on satellite images of regions including the Sahel, a semi-desert zone bordering the Sahara to the south that stretches some 2,400 miles (3,860 kilometers).

    Images taken between 1982 and 2002 revealed extensive regreening throughout the Sahel, according to a new study in the journal Biogeosciences. The study suggests huge increases in vegetation in areas including central Chad and western Sudan. In the eastern Sahara area of southwestern Egypt and northern Sudan, new trees—such as acacias—are flourishing, according to Stefan Kröpelin, a climate scientist at the University of Cologne’s Africa Research Unit in Germany.

    “Shrubs are coming up and growing into big shrubs. This is completely different from having a bit more tiny grass,” said Kröpelin, who has studied the region for two decades

    In 2008 Kröpelin—not involved in the new satellite research—visited Western Sahara, a disputed territory controlled by Morocco. “The nomads there told me there was never as much rainfall as in the past few years,” Kröpelin said. “They have never seen so much grazing land.” “Before, there was not a single scorpion, not a single blade of grass,” he said. “Now you have people grazing their camels in areas which may not have been used for hundreds or even thousands of years. You see birds, ostriches, gazelles coming back, even sorts of amphibians coming back,” he said.

    “The trend has continued for more than 20 years. It is indisputable.”

    http://www.sciencedaily.com/releases/2009/02/090218135031.htm

    Published today in Nature, the 40 year study of African tropical forests–one third of the world’s total tropical forest–shows that for at least the last few decades each hectare of intact African forest has trapped an extra 0.6 tonnes of carbon per year.

    The reason why the trees are getting bigger and mopping up carbon is unclear. A leading suspect is the extra CO2 in the atmosphere itself, which may be acting like a fertilizer. African forests have the highest mammal diversity of any ecosystem, with over 400 species, alongside over 10,000 species of plants and over 1,000 species of birds. According to the FAO deforestation rates are approximately 6 million hectares per year (almost 1% of total forest area per year), although other studies show the rate to be half that (approximately 0.5% of total forest area per year). The African Tropical Rainforest Observation Network, Afritron brings together researchers active in African countries with tropical forest to standardise and pool data to better understand how African tropical forests are changing in a globally changing environment.

  30. The greater availability of nitrogen in warmer soil, and plant response under those conditions is well known by any and all serious backyard veggie gardeners, and is the stuff middle school research projects are made of. How much to they pay for such knowledge? I’ll take mine in 5’s and 10’s please.

  31. After reading the methodology for the heating in this study, it does appear to have substantially more credibility than the typical Mythbusters’ approach. (they drive me nuts)

    5 KILOMETERS of cable??? That must have been fun for a bunch of grad students.

  32. “”””” Peter Dunford says:
    May 28, 2011 at 12:23 am
    Carbon dioxide is the most abundant greenhouse gas? “””””

    Not so; H2O is by far the most abundant greenhouse gas.

  33. 9°F! Given our cold,wet nasty spring in NE Oregon (due to a cold North Pacific IMHO,)
    I’d take it – nearer to Normal….

  34. “”””” charles nelson says:
    May 28, 2011 at 12:56 am
    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! “””””

    Well Charles, they said what they did; “warmed the trees”, and I presume that in their paper they state how they did that; and then they reported on what they observed happened as a result. Apparently the trees grew faster.

    I’m sure their experiment will be subject to debate, as to exactly what processes took place to yield the observations they made; i.e. the effect of their “warming” proess; but the fact remains (evidently) that they observed accelerated tree growth, as a result of an environment change, that included; but may not have been limited to, a “warming” of the environment.

    As to your “”””” … this 9 degrees F, not 10 or eight but 9… “””””, I don’t read anywhere that they say they turned up a “thermostst” dial by 9 deg F and the temperature increased by 9 deg F. They made some changes in the environment of that 1/4 acre, and apparently as a result, the observed temperature for that piece of forest increased by 9 deg F which they reported as the change. I am sure if their alterations had resulted in eight or ten degrees F rise, that’s exactly what they would have reported.

    Isn’t that how scientific experiments are done? You perform certain actions; and you observe, and report the results, and try to explain why you got the results you observed, as a cause and effect consequence of the actions you took.

    I won’t quarrel with your statements about the whole process, but it seems to me you are simply stirring a storm in a teacup.

    And by the way, I in no way endorse or bless their experiment, or their claimed causation. I’m just saying they properly reported on their experiment.

  35. The general public seems to think that plants grow by taking stuff out of the soil. If that were true, your geranium would need the soil replenished as it grew.

    Plants grow by taking in CO2. They strip the carbon out, and eject the oxygen. The carbon forms the plant cellulose. Conclusion: CO2 is good. More is better.

  36. charles nelson says:
    May 28, 2011 at 12:56 am
    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?

    It’s not April Fools day is it?

    They outdid themselves taking known facts and pretending to discover them.

  37. Smokey says:
    May 28, 2011 at 7:51 am

    Not only that, but the energy in the plant comes from the Sun, plus the building blocks for cells comes from water and minerals in the ground.

  38. “Tree growth in many of the forests in the United States is limited by the lack of nitrogen,”

    So pee on a tree to help the planet….simples.

  39. This experiment looks only at what happens with a far warmer atmosphere near the ground. It doesn’t look at what happens when CO2 is dramatically increased, which is what would cause the warming.

    This means that this experiment is missing at least two important effects, both of which have already been alluded to, but I want to state them explicitly.

    1. CO2 is plant food, and among other effects, it causes plants to be much more efficient in their use of water, because stomata on leaves don’t have to be open as much to bring CO2 into the plant. With less respiration of water to the air, because there are fewer stomata and they don’t have to be open as much, the plants will need less water. Thus, even in areas which in theory or actuality might become slightly more arid, this trend won’t hurt the trees because they won’t need as much water.

    2. CO2 per se causes plants to add more tissue, in this case more wood, until the growth rate bumps up against a limit of some sort (a nutrient, or a genetic limitation on size or growth rate). This experiment gave us the heat but not the plant fertilizer that causes greater productivity of the trees (remember the Idso’s famous experiments showing that you get something like 35% more oranges from your orange trees, everything else equal, with doubled CO2). There are many, many experiments showing greater productivity with more CO2. So this experiment underestimates the amount of CO2 that would be stored in trees, and MIGHT underestimate the amount stored in soil.

  40. So, with all the extra CO2 and additional photosynthesis we will, no doubt, end up with more O2. What does that cause at the other end other than more forest fires? AH, the multivariate, multicolinearity mish-mash deepens!! True idiocracy at work here.

  41. But this can’t be climatology, rediscovering the obvious and no computer models. The recognition (belatedly) of a well known fact plants grow better where its warmer and without extensive research travel too. So what is the principle electricity supply for the area? How many kW/h equivalent of CO2 emmissions did this experiment in ground heating produce? I see some hope these individuals may, could , might go on to do real research when they grow up, at least the methodology leans toward real science.

  42. To Mr Smith: the press report said “artificially warmed about 9oF above ambient, to simulate the amount of climate warming ..” So how do you go about changing the ambient temp in the a.m. that is 50F, noon which is 60F, 3pm which is ????, and so on, then there is wintertime temps. So it would be very interesting to know exactly how they did it. Thermostat?

    re cooling: We have irragation water that comes from snowmelt in the mountains a few miles up the canyon from my house. I wanted to plant my garden yesterday and wanted to use the “ditch” water. No water. Called the water master to see when they would turn on the water and he said “Have you seen the creek? It is bone dry. The snow has not started to melt yet.” We, in Utah, have up to 180% of normal snow pack. Snowbird ski resort will be open until July 4th for skiing for only the 3rd time in the last 40 years. Global warming????

  43. “… carbon dioxide … the most abundant greenhouse gas from the atmosphere …”

    Okay, I couldn’t read past that first paragraph after seeing this example of CAGW propaganda and intellectual dishonesty.

  44. “Warmer temperatures stimulate the gain of carbon stored in tree”

    A small correction should be made in the title, Anthony. I suppose you mean to say “higher temperatures”. A temperature is neither warm nor cold.

  45. DJ says:
    May 28, 2011 at 7:17 am

    After reading the methodology for the heating in this study, it does appear to have substantially more credibility than the typical Mythbusters’ approach. (they drive me nuts)

    5 KILOMETERS of cable??? That must have been fun for a bunch of grad students.

    I noticed that, also “buried by hand to minimize disturbance” and “Historical records, stone walls, and soil horizon characteristics indicate that the area was used for either pastureland or low-intensity agriculture before 1908.

    Stone walls and pasture land are strong indicators that the grad students had no fun whatsover. Last week my wife and I planted 100 white pine “seedlings” (2-3 yr old) on our property on the side of Mt. Cardigan in New Hampshire. The flatter terrain wasn’t too bad as a lot of fines washed down there during the glacial retreat to mix in with the rocks, but on the steeper terrain where I couldn’t get the shovel between rocks it was negative fun.

    I have a lot of respect for New England trees – thin soil, poor soil, 5-6 months of winter winds, and ice storms. Then we come along, cut them down and burn them for heat.

  46. The heating source was probably the same one “discovered” by NOAA, after which they quietly began removing said heat source. These researchers probably used the collected overturned boats, upright burn barrels, and BB Q’s stashed behind the NOAA office building of climate change. Scatter a few of those around a little piece of forest and abracadabra, 9 degrees of heating.

  47. I started to rip on this article but stopped myself – I realized at least these people are performing science – they didn’t just build a computer model and tweak it until they got the results they wanted.

    They used a control plot with unheated buried wire – good. They didn’t control air temperature, or add CO2 – weaknesses to the study. OK, I can find a lot to critique but again – at least they measured something.

    One little side note – I wonder if roots grow faster in the presence of alternating current (the electormagnetic waves caused by the current) and not just because they are warmer…That would be fun if true.

  48. It looks like one or two of us actually read the study, including the methods.

    What they did is bury soil heating wires 10 cm (~ 4 inches) deep and 20 cm (~8 inches) apart. The used a controller to keep the soil in the heated plot 5° C above the soil temp of the control plot, at one minute intervals – all year ’round. They did not alter the air temperature around the trees (other than what air layer may have been raised by the warmer soil, if any). They did not alter the CO2 levels of the air in either plot.

    With this methodology, I can not see how they could possibly draw any conclusions about the nitrogen or carbon cycles in a CO2-driven temperature enhanced forest.

    First, the idea that the soil temperature 4 inches down would be raised 5° C above ‘normal’, at every moment, year around is, I believe, fallacious, with any reasonably expected surface air temperature. I would have to see soil temperature graphs for soil temps against surface air temps at that depth. It seems incorrect to make the assumption that if average annual surface air temps rise 5° C that soil temps at 4 inches would also rise 5° C, every moment of the day, year around. Of course, no one expects that air temperatures will rise evenly by any X° C, 24 hours a day, year around, so the methodology does not represent any expected set of conditions to be measured.

    Secondly, they assume that the expected temperature increase would have been caused by ‘doubling’ of atmospheric CO2 (or some set amount of increased CO2). Yet, the experiment raises soil temperature only — not CO2 levels and not surface air temperatures. So we have warmed roots, but not warmed the trunk, limbs, and leaves. Further, measuring CO2/N cycles without actually increasing the CO2 levels expected to have caused the warming must throw all their respiration and CO2 processing data out of whack with any real world result. I see no way they could have controlled for these missing elements.

    The whole thing seems to be a bit like measuring the effects of fever on a human by warming just his feet, but not giving him any causative illness and its other symptoms. I will write to the lead author and ask him for a clarification.

  49. Instead of growing trees and then letting them decay and release carbon back into the atmosphere, what if we cut them down and sequestered them underground and then grew new ones and repeated the process? AND we could pay for the carbon sequestering, by using the trees for something productive BEFORE they were sequestered.

    I wonder if I could get a grant to study the economic feasability of this carbon sequestration project? Are there any WUWT readers that would like to particiapte? Think of all the new GREEN JOBS that this carbon sequestration project could support!!

  50. oakgeo says:
    May 28, 2011 at 10:05 am
    “’… carbon dioxide … the most abundant greenhouse gas from the atmosphere …’”

    “Okay, I couldn’t read past that first paragraph after seeing this example of CAGW propaganda and intellectual dishonesty.

    Thank you, thank you, thank you, Oakgeo! That was my first reaction, too. I went (current venacular) , ” WHAT!!!???” WUWT over the years has again and again published data on water vapor, which actually ‘absorbs’ long-wave IR better than CO2, is present in the atmosphere at levels ranging from 1% to 4% vs CO2 of a measly ~0.039%— 25 t0 100 times as much!

    Unbelievable!

  51. Anthony,

    The current Woods Hole study seems to answer the question of
    where, if at all, the “carbon sink” and carbon-nitrogen fixing is in
    forests with or without the increased CO2 levels as discussed in
    Hoosbeek et al,. and a whole series of similar studies:

    http://www.biogeosciences.net/8/353/2011/bg-8-353-2011.pdf

    which determined the “carbon sink” effect, thought to be in the
    sub-surface levels of a forests and most soil types was actually
    significantly observable in only the top 1 – 5 cm of the forest floor’s
    soil.

    The answer coming from this Woods Hole study of a forest
    that (1) hasn’t been previously used as farm land, (2) that’s being
    experimentally warmed to mimic hypothetical future atmospheric
    warming trends, (3) with the current real time rise and fall of New
    England CO2 levels from ~2003 to ~2010 as a present but
    uncontrolled (and unmentioned) variable:

    The “carbon sink” is, for the most part, the above- and below
    woody biomass of the trees themselves. The sub-surface nitrogen
    seems to be more “available” under these slightly warmer conditions
    for plant uptake, but not in a way that depletes the soil of it’s
    nitrogen levels.

    To many folks, this matches what they assume is just
    common sense as to the way the world works. However, in this
    area of environmental science, assumptions can’t be treated as
    facts until they’ve been vetted through experimentation and
    observation.

    The “woody biomass” of a forest, a.k.a. the TREES, wasn’t under
    consideration as an effective carbon sink in the Hoosbeek family
    of studies.

    Since the Woods Hole study wasn’t trying to demonstrate or
    “prove” anything about the effect of atmospheric CO2,
    most atmospheric CO2 level observations and discussion would
    be extraneous material.

    There’s absolutely no good evidence, at this time, that
    increased atmospheric temperatures of ~1 to ~2 or even ~5
    degree Celsius OR Fahrenheit would effect the forest soil
    temperature or composition to a depth or more than a couple
    of inches. Any discussion of deeper atmospheric temperature
    penetration of the soil would be both speculative and non-relevant
    to this particular Woods Hole study.

    The study brings existing environment science one baby step
    closer to reality.

  52. And there’s a side-effect as well: more trees for paper grocery bags! Since we’re not allowed to use plastic (evil Big Oil sourced) bags any more, and must use paper instead, this is great.

    Oh wait – moving to paper bags means less Evil Big Oil used, means less global warming, means slower growing trees… Well, crap!

  53. They would have done better with our money and their time, if they had spent seven years studying the avoidance of non sequiturs. They warmed 10cm of top soil by 5C with electricity from their nearest power station. Where, I wonder, do they think the business end of a hardwood tree is located? How far down do they think that additional heat extended? As an experiment to test the effects of warming arising from additional carbon dioxide they might just have well used their power grid to run an electric train set.

  54. “Jim G says:
    May 28, 2011 at 8:50 am

    So, with all the extra CO2 and additional photosynthesis we will, no doubt, end up with more O2. What does that cause at the other end other than more forest fires?”

    This will not be a concern. Suppose that the oxygen content is now 20.950% of the atmosphere. If enough carbohydrates are then burned to cause CO2 to go up by 0.010% then the oxygen would drop to 20.940% in the absence of any change in photosynthesis. But if we assume that 10% of the extra CO2 that we put into the air goes into increased photosynthesis, then the O2 drops to 20.941% instead of 20.940%.
    So the bottom line is that any extra photosynthesis just causes O2 to go down very slightly slower.

  55. @Interstellar Bill May 28, 2011 at 12:43 am:

    There won’t be any global warming, but a much greater stimulus to plants
    will be higher CO2.

    Bill, that was my first reaction, too. And I thought that maybe the experiment (an actual real world experiment in climatology – what a novel idea!) was missing the CO2 factor. But in reading more, I realized that this is the way you do science – by isolating factors (as much as you can) so that you can change one factor and observe/measure the results. This they seem to have done. And they did it while the CO2 was at a constant level (yes, the CO2 is essentially constant.). Doing this “changing one factor at a time” science is the best way – the only real way – to begin compiling a matrix of the factors (and determining which ones are not factors, too).

    @AndiC May 28, 2011 at 12:30 am:

    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?

    AndiC, this is actually a really good way to do this. By introducing an exaggerated increase (or decrease, in some cases), an experimenter can get a clearer signal from the results. It doesn’t mean the experimenter thinks that amount of increase is likely. As I understand it , this is the way carcinogen tests are done. No, nobody is going to ingest cyclamates at the rate those tests in the 1960s and 1970s were done – but with extremes comes more clarity of the results. Now they’ve got ONE piece of solid science. When perhaps another 15 to 20 such experiments are done, we will have enough pieces to put together. It would actually help, now that they’ve gotten this exaggerated test done – to clarify that there is a signal there – it would behoove them to now do gradations testing, to determine how lesser amounts affect trees, to come up with a quantified curve (exactly because of your point), so they will be able to begin to identify the effects of this/i> factor, when looked at in a matrix of other factors.

  56. Gary: “Did they also raise the CO₂by 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.”

    Exactly. If they simulated the temperature rise (a very large temperatures rise beyond all reasonable expectation) and did not include the large increase in CO2 that they propose will be the cause (with no evidence to date that such an amount of carbon is available on Earth) then it is not a particularly useful simulation.

    If the air had much more CO2 then the production of CO2 by the ground might be very different. Who knows?

    As CO2 fertilisation is well known to happen, then the trees might have put on far more mass than they did from just having a longer growing season.

    Also, if the Earth warms, then Northern forests will look a lot more like Temperate forests, growing much more as the season extends from say, 90 days to 130. For every degree of warmth and every 5 ppm CO2 increase there are tangible, measurable biospheric benefits only a portion of which were indicated by the experiment.

    It is not necesary to use a portion of a forest – any greenhouse with augmented CO2 (lots of them have it) can give accurate demonstrations of the benefits of heat and CO2 fertilisation.

  57. R.S.Brown says:
    May 28, 2011 at 12:07 pm

    > The current Woods Hole study …

    Pedantry alert – Woods Hole has offices for:

    Woods Hole Oceanographic Institute (WHOI – pronounced who-ee, not huey)
    Marine Biological Labratory
    National Fisheries
    US Geologic Survey (ocean floor core studies, I believe)
    Woods Hole Research Center (addresses the great issues for a healthy planet through science, education, and policy)
    J. Erik Jonsson Center of the National Academy of Sciences (conference center, not research).

    I’m surprised no one has pointed out MBL is a bit of an odd organization to be studying an inland forest, but I think it’s a continuation of the studies they’ve done in the coastal zone.

    At any rate – referring to a “Woods Hole” study is terribly ambiguous.

    There’s absolutely no good evidence, at this time, that increased atmospheric temperatures of ~1 to ~2 or even ~5 degree Celsius OR Fahrenheit would effect the forest soil temperature or composition to a depth or more than a couple of inches.

    Well, there are decent charts showing the “mean ground temperature,” which should increase with warmer surface temps (and air temp after accounting for evaporation). http://www.geo4va.vt.edu/A1/A1.htm , after the hot springs sections.

    However, for this experiment, roots are mainly in the top foot or two of soil and seven years of heating should get raise the soil temperature, at least to the water table.

  58. Trees and plants in general seem like a crazy idea for stashing CO2. Just like glaciers are a nutty way to provide fresh water. Assuming trees and plants die at the same rate they are created, the CO2 found in them is in a constant pass-thru state. Rotting plants put back into the system what they took from it while alive.

  59. @Feet2thefire: After skimming through all the responses here, yours is the only one I can really concur with. All those complaining that they did not ALSO change this and ALSO change that, and that the experiment is therefore meaningless, seem to understand nothing of how you isolate factors by changing one thing at a time. I know that from years of debugging computer code. The surest way of getting your t**s in a tangle is to change more than one thing at a time. This is fundamental to experimental technique. Thanks for the sane contribution.

  60. Ric Werme says: May 28, 2011 at 2:35 pm

    Ric,

    There’s no pedantry involved here at my end. The “current”
    study is the one under discussion, posted at the top of the thread.

    You said:

    At any rate – referring to a “Woods Hole” study is terribly ambiguous.

    What unmitigated whale drek. I didn’t refer to just “a” Woods Hole
    study, I referred to the one cited at the top of the thread. Also,
    above, at R.S.Brown says: May 28, 2011 at 1:51 am, I posted a
    clear link to the Woods Hole study at:

    http://www.mbl.edu/news/press_releases/pdf/pnas11_melillo_soilwarm.pdf

    You hadn’t entered into the commentary on the thread until about 4
    hours after that was posted. It was there for you to see. It should have
    given you some clue as to the Woods Hole study I was referring to then
    and later.

    Indeed, Anthony provided a link to the PDF of ” the current Woods Hole
    study”
    on the line just after the citation above. It’s the short line that
    says, “PDF of paper”.

    Clicking on that link also takes you to

    http://www.mbl.edu/news/press_releases/pdf/pnas11_melillo_soilwarm.pdf

    I figured most folks who would discuss the study and its results would
    actually read the PDF, which includes all the notations anyone
    would need to identify what division of Woods Hole was doing the work,
    and where the several authors were based.

    Your link:

    http://www.geo4va.vt.edu/A1/A1.htm

    is rather curious.

    Since the map used there in figure 2. shows “mean earth temperatures”
    as measured “in groundwater wells 30 to 50 feet deep”. It’s interesting, but
    seems to be little more that a digression or, more likely, a distraction from the
    thread’s topic.

    It’s meaningless to the study at hand.

  61. First, I will make a full disclosure- I did not read the study. But to those who did, did these researchers take into consideration and remove the effect of disturbing the compacted soil thus allowing more air into the ground, Kinda like aerating the soil, or oops tilling the soil to make plants grow better? I would like to know the grid spacing and how even the heat was dissapated, surely thay had lots of thermometers inserted thruout the experimental aera. Maybe the extra electromagnetic rediation thru the wires cause a new unknow CO2 and nitrogen magnet. Who knows the possibilities are boundless and endless

  62. I’ll bet commercial greenhouses around the world are so thankful for this discovery and are right now putting heating tape in the grow beds. And those of us who put in a garden every year are now retooling what we usually do in order to warm up the soil and keep it warm. In addition, the editors of Sunset Magazine are probably right now meeting in executive session to pore over the study results so they can write new articles on how to warm up soil. Thank God for climate change scientists.

  63. …pore… Sheesh. I could have sworn I typed “pour”. Too much Irish Cream in me mornin coffee.

    [I’d fixed it for you: pore n. be absorbed in the reading or study of : Heather spent hours poring over cookbooks. Next job: affect vs effect. Don’t know if I’m up to that one. ~dbs, mod.]

  64. “Jim G says:May 28, 2011 at 8:50 am So, with all the extra CO2 and additional photosynthesis we will, no doubt, end up with more O2. What does that cause at the other end other than more forest fires?”

    Bigger bugs?

  65. Ok, they changed one variable and measured the effects. Sounds like science.

    Now as to the comments about testing the extremes. I have done many experiments, and linear regression fits almost never work except in the extreme cases. There is almost always some sort of logarithmic or exponential zone followed by a more linear fit zone. A lot of data doesn’t even really seem to fit that pattern with slopes going the “wrong” direction for a bit then going back in the expected way. This seems especially true in biological systems for some reason. It is one of the reasons I wince at most of the graphs that show some sort of “almost sinusoid” with a local trend line that can change quite extensively depending on where on the “almost sinusoid” one chooses to look. By “almost sinusoid”, I mean a signal that looks like a sine wave, but when measured carefully has no consistent period and may even be somewhat chaotic (in the mathematical definition sense).

    Many chemical studies looking for carcinogenic effects were done in such a manner that dihydrogen oxide would have been banned as a hazard. Biological systems have a problem when one introduces extremely large quantities of almost any substance, especially if the introduction is sudden. I would hazard a guess that more careful studies of many of the banned chemicals would have found them safe or even beneficial at low dosages, but the extrema methodology eliminated that discovery. So I am not a fan of the extrema technique except as a way to explore extrema effects in conjunction with other experiments looking at the lower trends.

    The problem is the politics of science and this inane idea in society that we must eliminate all risk from the world. With this in place, we never do the finer grained studies because we are afraid that someone will read that “material X is beneficial” and not hear the part after that says “below Y milligrams per day.” No one wants to argue the science to a jury of people who likely won’t understand the data and will be swayed by the purely emotional appeal of the plaintiff’s attorney.

  66. Ok, I am now going to expose my ignorance, something I have been averse to doing for fear of ridicule…….

    What role does oxygen play, if any, in warming/cooling the atmosphere? Presumably, if all this extra CO2 allows more photosynthesis, more oxygen is released into the atmosphere. Then what? Nothing? Just more oxygen for us to breathe?

    My other question is about measurement of CO2 in the atmosphere. I seem to recall reading somewhere, here probably, that there is little exchange of air between the northern and southern hemispheres. In the northern hemisphere winter, deciduous trees lose their leaves and photosynthesis is reduced, so less carbon dioxide is taken out of the atmosphere than in the summer. The same applies in the southern hemisphere winter and summer. Presumably, then, carbon dioxide levels fluctuate between the seasons. When is it measured? All year round? Is a global average produced? A global average would, theoretically, produce a balance between northern and southern hemispheres, i.e. a northern winter reduction in CO2 absorbtion would be offset by the southern summer increase – or would it? There is a larger land mass in the northern hemisphere and a greater coverage of trees, so a northern hemisphere summer would give a global average reduction in CO2?

    Or am I just talking bo**ocks?

    Any answers (in simple terms, please – as you can tell, I am not a scientist) putting me straight would be more than welcome as I spend sleepless nights pondering this conundrum. (Well, not really.)

  67. strange surfacing to deal with when dealing with mother nature when releases or destroys”instruct best solution of balances which occuring for living/to be animals for dwelling dealing with the trees odors when in the atmosphere to communicate or move apart. side effects exists from some trees many shouldn’t be contended with/for others deadly if mind functioning wrong with the chemical its releasing from what isn’t yet is.

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