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Space Earth Science

Cosmic Radiation Makes Trees Grow Faster 162

Diamonddavej writes "The BBC reports that researchers at the University of Edinburgh have found that Galactic Cosmic Rays (GCRs) somehow makes trees grow faster. GCRs vary according to the 11-year solar cycle, with more GCRs hitting the Earth during solar minimum when there is a lull in the solar wind, which normally acts to protect the inner solar system from external galactic radiation. The mechanism might have something to do with GCRs increasing cloud cover, which diffuses sunlight and increases the efficiency of photosynthesis. Nevertheless, the researchers remain mystified and are requesting further ideas and research collaboration to test hypotheses. (How about Radiation Hormesis, AKA 'Vitamin-R?')" Here is the paper's abstract at the journal New Phytologist. The researchers say: "The relation of the rings to the solar cycle was much stronger than to any climatological factors. ... As for the mechanism, we are puzzled."
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Cosmic Radiation Makes Trees Grow Faster

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  • by JumperCable ( 673155 ) on Monday October 19, 2009 @10:29PM (#29803389)

    researchers at the University of Edinburgh have found that Galactic Cosmic Rays (GCRs) somehow makes trees grow faster

    I don't think they need to look any further for answers than the Fantastic Four.

    • I don't think they need to look any further for answers than the Fantastic Four.

      I don't think they need to look any further for answers than increasing carbon dioxide amounts somehow makes trees grow faster.

      (Really, it seems like this is to rebuff the notion that CO2 is Green [co2isgreen.org])

    • They doo in fact grow faster but get cancer.

  • by EdIII ( 1114411 ) * on Monday October 19, 2009 @10:31PM (#29803397)

    As for the mechanism, we are puzzled

    Geez and they're scientists? Just do a little research. I suggest Marvel Comics. Plenty of good info there. At the risk of starting war, I would caution them against research using DC Comics as they are for simple idiots that live in their mother's basements.

  • by wizardforce ( 1005805 ) on Monday October 19, 2009 @10:32PM (#29803409) Journal

    If the solar cycle is what determines the level of GCR that gets to Earth then it may very well have absolutely nothing to do with the tree growth its self but an indicator of solar conditions which influence tree growth rates.

    • Re: (Score:3, Funny)

      by socsoc ( 1116769 )
      But correlation is causation.
    • by khayman80 ( 824400 ) on Monday October 19, 2009 @11:28PM (#29803785) Homepage Journal

      That's what I'm thinking too. GCR intensity is highest when sunspot activity is lowest, generally modulating on an 11 year [nature.com] cycle. But solar irradiance also varies at the same frequency; the Sun is actually (~0.1%) brighter when more sunspots are present, contrary to intuition.

      If tree growth between 1953-2006 really is highest when sunspot activity is lowest, that implies trees grow faster when the Sun is very slightly dimmer. Weird. Their diffusion explanation makes sense, but as they note this cloud condensation effect is supposed to be a very small effect. Perhaps it's just large enough to be noticed in these proxy data, though. I agree, however, that a link to solar irradiance is more intuitively appealing, and it's not immediately obvious how it could be ruled out.

      I'd bet they've already considered this issue and ruled it out, possibly by using satellite measurements of solar irradiance and solar wind over the last few decades. They're supposed to be tightly correlated, but if the solar wind varies even slightly differently than solar irradiance it should be possible to see which is causing this variation in growth rates.

      • Re: (Score:3, Informative)

        by Eukariote ( 881204 )

        Though there is little variation at visible and near UV wavelengths, the solar flux has a huge (factor of three) variation with the solar cycle in the extreme UV: http://www.usc.edu/dept/space_science/sem_data/SEM%20Data%20Graphs/SEM_1996-2009.jpg [usc.edu].

        EUV and X-ray photons constitute a marked fraction of the total solar output. A much larger fraction than you would expect from the short-wavelength tail of the black-body spectrum of the solar surface. Indeed, these emissions are mostly from the corona, not the s

      • that implies trees grow faster when the Sun is very slightly dimmer

        Didn't we learn from Intro to Biology that plants grow on the side facing away from the sun? That direct sunlight inhibits growth?

        • Most plants exhibit positive phototropism; i.e. they grow towards light. I'd think that more sunlight = faster growth, as do the researchers in the article because they reason that higher GCR intensity = more clouds = more diffuse light = easier to penetrate forest canopy = more light available to plants = faster growth.
          • Most plants exhibit positive phototropism; i.e. they grow towards light.

            Right, because the cells facing away from the light are the ones growing at the faster rate, so the net is that the plant as a whole grows towards the light (the faster-growing cells become the outside of the curve).

            • Interesting, I hadn't thought of it that way. Plants have evolved to orient towards the Sun in order to maximize growth rates (presumably- otherwise why would this strategy be selected for?) This implies that cells receiving less light than other cells in the same plant will grow faster in order to point the leaves towards the Sun, thus maximizing the plant's overall growth rate. I thought you originally meant a plant would grow faster on the shaded side of a hill than on the sunnier side, but I now underst
              • I'm still not sure this effect would occur if the overall light intensity changed-- it seems like an effect that depends on relative differences in light intensity.

                Good question - as I recall the sunlight has an inhibitory effect (the plants still grow at night), but _all_ of this is from my freshman in high school bio class. I had a super good teacher, but I'm certainly no botanist.

    • by mrmeval ( 662166 )

      What if trees detect that there is a solar minimum and grow bigger in response to it because trees that grew bigger in the past during solar minimums survived.

    • by hawkfish ( 8978 )

      If the solar cycle is what determines the level of GCR that gets to Earth then it may very well have absolutely nothing to do with the tree growth its self but an indicator of solar conditions which influence tree growth rates.

      I suspect this is related to one of the current global warming contrarian canards - that GCRs are responsible for increased cloud formation which in turn produces a warmer climate due to more atmospheric water acting as a GHG. Needless to say, the contrarian "science" there is as bad as it is everywhere else...

  • by Korbeau ( 913903 ) on Monday October 19, 2009 @10:33PM (#29803413)

    in one, two, tree ...

  • Cloud cover (Score:5, Interesting)

    by MichaelSmith ( 789609 ) on Monday October 19, 2009 @10:38PM (#29803447) Homepage Journal

    The mechanism might have something to do with GCRs increasing cloud cover, which diffuses sunlight and increases the efficiency of photosynthesis.

    How about cloud cover leads to more precipitation?

    • Re: (Score:3, Insightful)

      by pclminion ( 145572 )

      How about cloud cover leads to more precipitation?

      No. Precipitation cannot be larger than evaporation. Evaporation is heat driven, and cosmic rays do not input enough heat energy to significantly contribute to evaporation.

      • Re:Cloud cover (Score:4, Insightful)

        by MichaelSmith ( 789609 ) on Monday October 19, 2009 @10:52PM (#29803547) Homepage Journal

        How about cloud cover leads to more precipitation?

        No. Precipitation cannot be larger than evaporation. Evaporation is heat driven, and cosmic rays do not input enough heat energy to significantly contribute to evaporation.

        Radiation nucleates droplets in clouds so that water vapor precipitates where it otherwise would have stayed in the atmosphere. Its a bit like how dust from outer space contributes to rainfall by encouraging the formation of drops big enough to fall as rain.

        • That's a nice hypothesis to test, if you also collect rainfall data.

          I was also thinking about DNA damage caused by radiation. All organisms are resilient to some low levels of radiation, or DNA molecular damage caused by even oxidizers/chemicals, heat, or radiation, and have sophisticated self-repair functions. Aging is deliberate built in function in all known multicellular organisms, caused by a counting mechanism that counts how many times the individual cells have divided - bacteria live indefinitely
          • That's just what they want you to think.
          • Comment removed based on user account deletion
        • Radiation nucleates droplets in clouds so that water vapor precipitates where it otherwise would have stayed in the atmosphere. Its a bit like how dust from outer space contributes to rainfall by encouraging the formation of drops big enough to fall as rain.

          It can certainly induce local rainfall, but neglecting a feedback effect, it can't make the entire planet "rainier" because there is no increased input of water vapor to the atmosphere.

      • No. Precipitation cannot be larger than evaporation. Evaporation is heat driven, and cosmic rays do not input enough heat energy to significantly contribute to evaporation.

        Well, clouds are good at trapping heat near Earth's surface.

        Also, locally, precipitation is very often larger than evaporation. Maybe more clouds over land doesn't have much to do with evaporation at sea.

        There's also this feedback effect that slightly more heat means more water vapor, which is a strong greenhouse gas and thus means more heat.

    • by pz ( 113803 )

      The mechanism might have something to do with GCRs increasing cloud cover, which diffuses sunlight and increases the efficiency of photosynthesis.

      How about cloud cover leads to more precipitation?

      Right. Correlation is not causation, no matter how hard you wish it so. Another hypothesis is that GCRs -- since they are observed to vary with the solar cycle -- are an epiphenomenon, and the real driving force is the solar cycle.

      Nothing to see here but another ill-thought-out observation of which there are plenty. The 11-year solar cycle also drives the insolation (amount of light hitting the earth), the magnetosphere, the amount of accreted cosmic dust, the aurora borealis, the cloud cover, the sea le

  • by Shaterri ( 253660 ) on Monday October 19, 2009 @10:46PM (#29803493)

    Especially in a case like this, where there are other tightly-correlated variables. Why is the authors' presumption that it's the cosmic rays (or lack thereof) that are regulating tree growth, rather than solar and sunspot activity itself? It seems at least as plausible to me that sunspot activity correlates to some other solar features (e.g., solar irradiance) that would have a more natural and direct effect on tree growth than cosmic rays.

    • by MichaelSmith ( 789609 ) on Monday October 19, 2009 @10:49PM (#29803525) Homepage Journal

      Are you saying that tree growth may be causing cosmic radiation?

      • Re: (Score:3, Funny)

        by Anonymous Coward

        it's the butterfly effect or something

        • by CptNerd ( 455084 )
          Irradiated butterfles?

          (which, BTW, would be a great name for a rock band)

          (so would "Galactic Cosmic Rays". Just sayin'.)
    • Why is the authors' presumption that it's the cosmic rays (or lack thereof) that are regulating tree growth, rather than solar and sunspot activity itself?

      Because he has a statistical correlation showing that when comic rays increase, plant growth also increases? FTFA:

      When the intensity of cosmic rays reaching the Earth's surface was higher, the rate of tree growth was faster. The effect is not large, but it is statistically significant. The intensity of cosmic rays also correlates better with the changes in tree growth than any other climatological factor, such as varying levels of temperature or precipitation over the years.

      Also interesting for those mentioning sunspots FTFA:

      The levels of cosmic rays reaching the Earth go up and down according to the activity of the Sun, which follows an 11-year cycle. As for the mechanism, we are puzzled Sigrid Dengel University of Edinburgh Every 11 years or so, the Sun becomes more active, producing a peak of sunspots. These sunspots carry a magnetic field that blocks and slows the path of energetic particles. When the researchers looked at their data, they found that tree growth was highest during periods of low sunspot activity, when most cosmic rays reached Earth. But growth slowed during the four periods of cosmic ray-blocking high sunspot activity, which have occurred between 1965 and 2005.

  • by eldavojohn ( 898314 ) * <eldavojohn@noSpAM.gmail.com> on Monday October 19, 2009 @10:49PM (#29803519) Journal
    What else grows from radiation? Cancer. Quod erat demonstratum, trees are cancer. Therefore we must cut them down and burn them. Perhaps form some sort of industry devoted to this.

    What? The "logging" industry? Oh, well, very good then. Continue.
  • Now everyone with a grow op in their basement has to go out and buy new fancy lights which give off Galactic Cosmic Rays.

    -hps

  • Cause increased carbon sequestration by bombarding the Earth with radiation! This also has the beneficial side-effect putting an eventual end to homocentric global warming.
  • They used to grow plants with radiation in the soil because it would cause them to grow faster. However, the problem is that this would irradiate the food that grew off of these plants.
    • Re:Once upon a time (Score:4, Informative)

      by wizardforce ( 1005805 ) on Monday October 19, 2009 @11:21PM (#29803743) Journal

      objects do not become radioactive unless they are bombarded with neutron radiation, high energy protons or extremely high energy gamma radiation capable of ejecting a proton or neutron to form a radioactive isotope. Simply irradiating an object does not necessarily make the object radioactive. Now in so far as plants having a higher growth rate due to radiation, I haven't heard much on the subject other than radiotropic melanized fungi [wikipedia.org] living near Chernobyl having a substantially increased growth rate.

      • by jamesh ( 87723 )

        objects do not become radioactive unless they are bombarded with neutron radiation

        Contrary to what you might have heard, plants don't just absorb water from their roots - they also absorb minerals etc. If any of the minerals in the soil that the plant absorbs happen to be radioactive then we have a problem. If the plant then enters any part of the food chain that ends with humans then we have a bigger problem.

        • My post did not contain that information because I was responding to his concerns that irradiating food causes the food to be radioactive and to me it goes without saying that if something is already radioactive it will cause problems.

        • by TheLink ( 130905 )
          Wonder what would happen if you used a geiger counter on a container filled with brazil nuts :).
  • from many years ago. The experiment was two identical growing chambers using artificial sunlight. One was placed in a normal building, the other underneath a mountain or something shielded from cosmic rays like that. It had the same result: it was found that plants grew better when they were getting the radiation. Does anyone remember this experiment?

  • Damn, when I looked at it, I thought for sure it said "radiation horniness" -- following the sunspot cycle?

    Why not?

    People working with long distance radio communications -- whether it's LF for ships, ham radio, or spacecraft, knows the incredible variation the sunspot cycle can have on communications -- there are enormous swings in energy levels involved. Why shouldn't it show up in complex systems such as trees?

    And yes, the link may be indirect, it may not be direct causation, merely correlation, but
  • by bigsexyjoe ( 581721 ) on Monday October 19, 2009 @11:38PM (#29803845)
    The cool thing is that you get super powers from eating the giant vegetables, too.
  • Paul Zindel (Score:3, Funny)

    by sohp ( 22984 ) <.moc.oi. .ta. .notwens.> on Monday October 19, 2009 @11:48PM (#29803893) Homepage

    A 1964 publication by Paul Zindel entitled "The Effect of Gamma Rays on Man-in-the-Moon Marigolds" predates this research by quite a bit.

  • Nitrogen Fixation (Score:5, Insightful)

    by physburn ( 1095481 ) on Monday October 19, 2009 @11:49PM (#29803903) Homepage Journal
    This is an easy mystery to solve. When a cosmic ray hits the atmosphere, it creates a shower of ionizing radiation, each of the secondary particles are enough to ionizing oxygen and nitrogen molecules in the atmosphere, forming nitrogen oxides, these react ready with water forming nitric acid, which will precipitate in dilute form in the rain. Only lightning and cosmic rays can form nitrogen oxide, and lightning is relatively rare, so the amount of available free nitrates in the soil, depends very much on the amount cosmic rays hitting the earth.

    Plants of course need nitrogen to grow, the trouble is they can't absorb nitrogen from the atmosphere (except for Legumes (pea, and beans and similar plants)). So for the majority of plants and trees, not feed by human fertilizers, the amount of fertilizing nitrate available to them, is directly proportional the cosmic ray flux.

    Mystery Solved.

    ---

    Dark Matter [feeddistiller.com] Feed @ Feed Distiller [feeddistiller.com]

    • Don't forget vehicle exhausts as a potential source of nitrogen oxides.

      Perhaps we should get rid of modern three-way catalytic converters [wikipedia.org] and bring back the old two-way ones, in the interests of saving the planet and/or growing mutant super trees.

    • Re:Nitrogen Fixation (Score:4, Interesting)

      by AJWM ( 19027 ) on Tuesday October 20, 2009 @01:45AM (#29804445) Homepage

      Only lightning and cosmic rays can form nitrogen oxide, and lightning is relatively rare,

      Well no, lighting is fairly common, actually -- there's always a lighting storm going on somewhere. However, if one assumes that the global rate of lightning is fairly constant then given that the amount nitrogen oxides contributed by cosmic rays fluctuates, you'd still see a correlation. So you may be right.

      • Well no, lighting is fairly common, actually -- there's always a lighting storm going on somewhere.

        Oh, that's just The Cheat having one of his low-budget raves.

    • Wow. If correct, (a quick Google of 'cosmic radiation nitrogen fixation' returns this article as the first result...) this is probably the most informative on-topic comment I've ever seen on a Slashdot post.
      Kudos.
      • That's just Google being quick at indexing. Google finding it doesn't make it true. Somebody would have to do an calculation of amounts of nitrogen oxides made by cosmic rays against other source and, measure what fraction of tree growth is rate limited by nitrate abundance, to confirm it. But thanks mightily for the praise.
    • Nitric acid is also an electrolyte. I hear those are what plants crave.
    • by geekoid ( 135745 )

      "and lightning is relatively rare, "

      HAhAHAHAHahahha.. no, it's not.

  • I thought this was thoroughly debunked already.
  • The professor in Gilligans Island already determined this. Old news, nothing new here.

  • Homer: If we learned one thing from "The Amazing Colossal Man" and "Grasshopperus," it's that radiation makes stuff grow real big, real fast.
  • by kauttapiste ( 633236 ) on Tuesday October 20, 2009 @02:03AM (#29804507)

    Nevertheless, the researchers remain mystified and are requesting further ideas ...

    Have they considered Ask Slashdot?

    • Nevertheless, the researchers remain mystified and are requesting further ideas ...

      Have they considered Ask Slashdot?

      That is not actually a bad idea. Just on this thread, there have been several ideas that merit exploration (although any and all of them may already have been examined and found wanting). Of course there have also been several ideas that are complete bunkum (a couple proposed as jokes a couple seriously).
      If you have an observation that is not readily explained by existing mechanisms, posting a question on Slashdot looking for ideas to examine is not the worst thing you could do. I am sure there are other

  • by foobsr ( 693224 ) on Tuesday October 20, 2009 @03:40AM (#29804913) Homepage Journal
    Quote [complexsystems.net.au]:"One of the reasons people have difficulty in dealing with complex systems is that the linear causal chain way of thinking - A causes B causes C causes D ... etc - breaks down in the presence of feedback and multiple interactions between causal and influence pathways. One could say that complex systems are characterised by networked rather than linear causal relationships."

    Keeping that in mind, I tend to be of the opinion that the best guess regarding an isolated cause is '42'.

    CC.
  • Sun spots (Score:3, Interesting)

    by Anonymous Coward on Tuesday October 20, 2009 @05:39AM (#29805415)

    At the university I studied physics at, they had a nice (old) telescope with which they projected solar images to count sun spots. They had a graph on the wall of the number of sun spots, going decades back. There was a nice periodicity in that graphc, and interesting thing is that they could point out two types of events: good wine years, and the occurrence of the "Elfstedentocht" (a major Dutch ice skating event which only happens when the outdoor ice conditions are exactly right).

    I forgot which one happened at sunspot maxima and which at the minima, but there was a striking correlation.

  • And weather could be affected by solar cycles. The correlation is there, but not a clear causal link. Solar minimums tend to be cooler periods, e.g. 2008 & 2009.
  • If this really shows a causal link between cosmic rays and tree growth, you can bet it won't be long before it's pointed out that cosmic rays therefore impact the biospheres carbon absorbtion rate. Which is interesting. This will be misused by climate change denialists.
  • "The BBC reports that researchers at the University of Edinburgh have found that Galactic Cosmic Rays (GCRs) somehow makes trees grow faster.

    That conclusion is so distant from the data as to be completely misleading.

    What they really found was that tree growth rate in one particular site in Scotland seems to show an eleven-year cycle over the last fifty-three years (i.e., not quite five periods). The eleven year cycle was then connected with sunspots via this reasoning: "Hey, sunspots have an eleven-year cycle, too!". And then the mechanism was suggested: "Hey, galactic cosmic rays vary with the number of sunspots!"

    The purported connection fr

  • IF there is a true connection, then it should not be so mystifying. Radiation has been shown, in studies, to make animals healthier in low doses (i.e more than background radiation, but less than what you'd want to monitor). The reasoning was that it 'stressed' the animals systems, making them stronger, and thus healthier overall. The same could apply to trees - Cosmic rays may 'stress' them, causing them to grow faster as a result (trying to compensate).

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