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Earth Medicine Science

Death of Trees Correlated With Human Cardiovascular & Respiratory Disease 152

Posted by Soulskill
from the newspapers-now-a-public-health-menace dept.
eldavojohn writes "PBS's NewsHour interviewed Geoffrey Donovan on his recent research published in the American Journal of Preventative Medicine that noted a correlation between trees (at least the 22 North American ash varieties) and human health: 'Well my basic hypothesis was that trees improve people's health. And if that's true, then killing 100 million of them in 10 years should have an effect. So if we take away these 100 million trees, does the health of humans suffer? We found that it does.' The basis of this research is Agrilus planipennis, the emerald ash borer, has systematically destroyed 100 million trees in the eastern half of the United States since 2002. After accounting for all variables, the research found that an additional 15,000 people died from cardiovascular disease and 6,000 more from lower respiratory disease in the 15 states infected with the bug, compared with uninfected areas of the country. While the exact cause and effect remains unknown, this research appears to be reinforcing data for people who regularly enjoy forest bathing as well as providing evidence that the natural environment provides major public health benefits."
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Death of Trees Correlated With Human Cardiovascular & Respiratory Disease

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  • by pepty (1976012) on Tuesday June 11, 2013 @03:04PM (#43976991)
    and posting your indignant observation, please check and see if they did.
    • Want to bet that this will be exhibited soon as a poster child of spurious significance and poor statistical analysis?

    • by Synerg1y (2169962)

      http://www.ncbi.nlm.nih.gov/pubmed/23332329 [nih.gov] you go first, I see none.

      Anyways, it makes sense that air quality is worse in areas with less trees leading to higher rates of lung disease, but we didn't need this study to affirm that. Just drive in a major city on a hot afternoon and check out the smog.

      • by gstoddart (321705) on Tuesday June 11, 2013 @03:19PM (#43977187) Homepage

        There's things you think you know that are obvious, and then there's actual science.

        Sometimes, you need the proper study just to verify your hunch isn't entirely wrong -- everything else is an anecdote or a guess.

        • by Anonymous Coward

          There's things you think you know that are obvious, and then there's actual science.

          There are obvious obviouses; there are things we obviously know are obvious.
          There are obvious deepnesses; that is to say, there are things we obviously know are quite non-trival.
          But there are also deep deepnesses – there are things about which we don’t have a freaking clue.

          Sometimes, you need the proper study just to verify your hunch isn't entirely wrong -- everything else is an anecdote or a guess.

          You publish with the study you have---not the study you might want or wish to have at a later time.

        • by sjames (1099)

          And then there's people who after having an eye poked out will refuse to draw any conclusions about eyes and vision until they poke the other eye out.

          • by pspahn (1175617) on Tuesday June 11, 2013 @04:03PM (#43977683)

            Speaking of poking out eyes, I have long known that EAB (Emerald Ash Borer) has been affecting human health, and you would too if you watch much baseball.

            The death of ash due to EAB has caused a significant uptick in the amount of bats made from maple instead of ash. Maple doesn't have the same kind of durability that ash does, and what you end up with are bats that are easier to break. On any given night, you can see highlights of some pitcher nearly losing his face because a large chunk of maple is flying at him. You almost never saw this when bats where made exclusively from ash, as maple is simply more brittle and not as elastic.

            Save a pitcher, plant an ash!

            • by sjames (1099)

              It is pretty scary to see bat fragments flying nearly as far as the ball night after night. It's a miracle we don't see more injuries.

              At least it's not as bas as it was a couple years ago when it seemed like every hit broke a bat.

              • That was the fault of cork, not maple.

                • by sjames (1099)

                  While there have been a few proven instances of corked bats, that's not what was happening there (since if your corked bat shatters, you're busted).

                  The superball bat must have been fairly amusing when it broke.

            • by cellocgw (617879)

              The problem w/ bats breaking could have been very easily solved by switching to metal bats. And before you go all "but they're much too powerful" on me, metal (or any composition) bats can be designed with any size sweet spot and coefficient of rebound you want. They currently get designed to maximize output so as to let ballplayers think they're the offspring of Babe Ruth and Ted Williams.

              Or better yet, let's design bats out of tempered glass, like Prince Rupert's teardrops, so a mis-hit leads to a showe

          • there's people who after having an eye poked out will refuse to draw any conclusions about eyes and vision until they poke the other eye out.

            That statement is SO out of date. The new phrasing is "Do not look into laser with remaining eye."

        • Sometimes, you need the proper study just to verify your hunch isn't entirely wrong -- everything else is an anecdote or a guess.

          Or exploratory research. :)

      • Anyways, it makes sense that air quality is worse in areas with less trees leading to higher rates of lung disease, but we didn't need this study to affirm that. Just drive in a major city on a hot afternoon and check out the smog.

        That wouldn't tell you if it was the trees that made the difference. To say that, you'd need to go to a forested area, kill the trees, then compare health before to after. Or, in this case, allow insects to do the killing.

      • by skids (119237)

        Anyways, it makes sense that air quality is worse in areas with less trees leading to higher rates of lung disease

        Given the plumes of VOCs trees emit, no that makes no sense at all. Now, having a bunch of dead decaying trees lying around after being killed by an infestation, THAT impacting air quality would seem to make sense.

    • by Nathan Bubna (2882333) on Tuesday June 11, 2013 @03:18PM (#43977171)

      Sorry but the very phrase "After accounting for all variables" when doing statistical analysis on any complex real-life scenario is laughable. We don't even know all the variables, much less have rigorous data for them all.

      I think their theory is probably right. It makes a lot of sense and the data we do have does fit. But this is statistics, not science; correlation, not proof of causation. It is far from being without value, but it is also far from being conclusive or thorough. It is merely as thorough as it could be given available data.

      • Would you know what to do with the data if the author provided it?
        Have you read the linked article to determine what should have been accounted for, but was not?
        • by repvik (96666)

          Irrelevant. We cannot possibly know "all variables" - and thus stating that all variables have been accounted for is bunk.
          However, that doesn't mean that the study is wrong - it's just not good enough.

          • by sjames (1099) on Tuesday June 11, 2013 @03:51PM (#43977541) Homepage

            By that criterion, no study of anything ever has been good enough because we NEVER know for a fact that we have covered all variables.

            'good enough' is only knowable in retrospect since at the time, we (by definition) didn't know about the unknown variables..

            • by famebait (450028)

              Granted, repvik goes a bit too far. The claim of controlling for all factors remains irrevocably bunk, but that does not in itself mean the study is not good enough - it merely reflects poorly on the source of that claim. Which brings us to the crux: who is that source? Does the actual publication make this extraordinary claim, or is it merely a perversion introduced by someone else along the chain from there and to this comment?

              • by sjames (1099)

                I don't see any claim by the researchers of that nature in TFA or the abstract. It must have been later in the chain.

          • How would you KNOW its 'not good enough'? What would even define something as not good enough? This is a stastical study. It demonstrates certain correlation (R) factors between variables. This suggests there is a causal relationship, either direct or indirect. If you are going to say that "because there could be confounding factors that haven't been factored out" the study is automatically worthless then you have just rejected 99.9% of all the scientific research ever done. It makes no sense at all.

            Clearly

  • by etash (1907284) on Tuesday June 11, 2013 @03:05PM (#43977007)
    a cabin in the woods? complete with a cinema nearby, hospital, supermarket, grocery and all the facilities we need every day..well maybe some small roads connecting them..oh wait!
    • by Drethon (1445051)
      Yeah I live there. Creeks run through the city around Grand Rapids and the woods are still there. Find a house where the property ends in such woods. Not necessarily in the woods but close enough for me.
  • Bad science (Score:3, Insightful)

    by girlintraining (1395911) on Tuesday June 11, 2013 @03:08PM (#43977043)

    Take a good look guys. This guy just committed a basic mistake in method. He made a leap unsupported by the facts. The presence and quantity of trees may be correlated with healthier people, but that in no way means there's a connection. He hasn't controlled for environmental factors. The most basic would be answering the question -- why are there more trees in a given area? In densely populated urban areas, there will be fewer trees, obviously... and we know cities have more pollution than a prestine wilderness. But that doesn't mean the trees are what's making people healthy... it could just be that the absence of pollution is.

    This is an incomplete analysis and an attempt by an amateur scientist to start with a conclusion and work his way back to find supporting facts, while ignoring the fact that in science, you do things the other way around. And if you don't, you get crap like this.

    I'm not about to go throw myself in a lake and start tree bathing because I think it'll improve my health... at best it'll be a placebo reaction. At worst, it'll kill me due to my allergies. What I'd do instead is try to find populations where trees are present at various threshold concentrations and match the environments as closely as possible so the only control would be the number of trees in a given area, and see if the correlation still holds.

    Oh, and something to be aware of... richer neighborhoods have more trees than poorer neighborhoods, to the point that if you take satellite photography of a large metropolitan area, that alone can predict to a high degree of accuracy where the rich people live. Is this because they can afford to keep their environment cleaner as well?

    You have to control for human behavior in this, or your analysis is broken.

    • Mod parent up. The proposed hypothesis does not include a necessary and sufficient statement of falsifiability.

      • by sjames (1099)

        So finding no correlation wouldn't falsify a hypothesis that there is a correlation?

        • The hypothesis posited wasn't one of correlation. From TFA:

          "'Well my basic hypothesis was that trees improve people's health"

          That's a hypothesis of causality. Trees *cause* an improvement in people's health.

          While finding no correlation may be good enough to exclude that hypothesis, finding correlation is *not* sufficient to lead us to believe in his preferred causality direction.

          There are three primary options we must consider when looking at causality within a correlation -> A causes B, B causes A, or

          • by sjames (1099)

            Keep in mind that the wording in an informal interview for laymen may not be exactly the same as in your formal write-up.

            Also, since they don't claim to prove that the trees improve health, but only to support that conclusion, the constraint on the hypothesis is similarly relaxed.

            • You make a good point - science by press release is notorious for turning the most dull and meaningless paper into something exciting and eye catching. Sadly, both the press and the scientists involved are often complicit in the hyping of data in order to garner attention and ultimately funding, either in terms of grants or advertising.

              As for supporting any conclusion, they could also have said that health improves trees - their choice of *which* implication to highlight (though neither is proven) is an ex

    • by aflag (941367)
      Have you read tfa?
    • Re:Bad science (Score:5, Informative)

      by Anonymous Coward on Tuesday June 11, 2013 @03:24PM (#43977237)

      > Take a good look guys.

      Too bad you didn't.

      > -- why are there more trees in a given area

      Isn't what this work studied. They correlated a specific insect cause of tree death with human welfare. The methodology was specifically constructed to remove confounding factors— things like air pollution killing both the trees and the humans.

      That isn't to say the research is flawless but it was deeper and more carefully constructed that your slashdot arm-chair-expert off the hip comment gives it credit for.

      • Isn't what this work studied. They correlated a specific insect cause of tree death with human welfare. The methodology was specifically constructed to remove confounding factorsâ" things like air pollution killing both the trees and the humans.

        What is testing has, at best, a loose relation with what it set out to prove. The test was "the loss of 100 million trees to the emerald ash borer", but they looked at "the relationship between emerald ash borer presence and county-level mortality." These aren't the same thing. What they were looking at was how many of these insects were present. They concluded that the more of these insects in the area, the higher the mortality rate. The trees are the insects principal food, and it's easier to measure the

    • While healthy cynicism is good in all things, did you not see this bit:

      while controlling for a wide range of demographic covariates

      as pointed out earlier here [slashdot.org]?

    • Re: Bad science (Score:4, Insightful)

      by stranger_to_himself (1132241) on Tuesday June 11, 2013 @03:31PM (#43977295) Journal

      There's no claim that health was correlated with the presence of trees. The claim is that health is correlated with the presence of something that kills the trees, effectively at random (or at least in a way which is uncorrelated with anything that also directly affects human health) making this quite a neat natural experiment. Your arguments about other confounding factors don't hold in this case. look up natural experiments or instrumental variables if you want to know more about the method.

      • by CAIMLAS (41445)

        Yep. As someone who loves the outdoors and intentionally does not have air conditioning (so the windows will be open, letting in the nearby forest breezes in), I would be very curious to see how it correlates with the local tree-killing pest: pine beetles. That's more of a "western states" problem, since we don't have nearly as many aspen and other deciduous trees here.

      • There's no claim that health was correlated with the presence of trees.

        From the summary of the article::

        'Well my basic hypothesis was that trees improve people's health.

        • There's no claim that health was correlated with the presence of trees.

          From the summary of the article::

          'Well my basic hypothesis was that trees improve people's health.

          Yes - that's the hypothesis, but the evidence to support it doesn't come from an observed correlation between trees and health, as previous people have said that would be confounded will all kinds of other factors which would be impossible to measure. The evidence comes from the observed correlation between the pest and health, which is presumably (and this is big assumption) not confounded with other factors, with the presence of trees as the only possible mediating factor.

    • by pepty (1976012)

      But that doesn't mean the trees are what's making people healthy... it could just be that the absence of pollution is.

      I agree they needed better matching controls in the study, but one thing trees do in urban environments is help remove air pollution.

      • Re:Bad science (Score:4, Interesting)

        by pspahn (1175617) on Tuesday June 11, 2013 @04:19PM (#43977861)

        Not only that, but ash are a tree that does this better than others. There is a reason ash are commonly used as a 'street tree', and that is because they are effective cleaners of the particulates in the air while remaining healthy themselves.

        I think an interesting extension of the study would be to look at any similar effects found in the West as a result of MPB (Mountain Pine Beetle). I'm not sure how different the loss of biomass is between MPB and EAB, but I can say I've never seen ash forests tens of thousands of acres in size be completely devastated where tree mortality is clearly over 90%.

        With MPB, you have a much larger (and concentrated) loss of biomass while at the same time it is occurring in less densely populated (human-wise) geographies.

        • by pepty (1976012)

          I'm not sure how different the loss of biomass is between MPB and EAB, but I can say I've never seen ash forests tens of thousands of acres in size be completely devastated where tree mortality is clearly over 90%.

          With MPB, you have a much larger (and concentrated) loss of biomass while at the same time it is occurring in less densely populated (human-wise) geographies.

          I think pine trees might actually be a net source of particulates as far as air pollution goes. They emit a lot of terpenes, which get turned into particulates in sunlight. How about Elm trees? There are plenty of neighborhoods in the midwest that lost 90%+ of their elms due to Dutch Elm disease. The house where I grew up lost 4 out of 5 in as many years, each easily 50 feet wide at the crown.

    • Re:Bad science (Score:5, Informative)

      by Baloroth (2370816) on Tuesday June 11, 2013 @03:45PM (#43977465)

      Seriously, did you even read the damned summary before you post? They controlled for demographic variables over time. The exact quote from the abstract is "Two fixed-effects regression models were used to estimate the relationship between emerald ash borer presence and county-level mortality from 1990 to 2007 in 15 U.S. states, while controlling for a wide range of demographic covariates." But yeah, I'm sure you identified the major problem with the whole study in 10 seconds. A study that was done over several years analyzing 17 years of collected data. But it's wrong, because there is absolutely no way they thought to correct for human behavior, no matter what the summary says.

      Oh, hey, whats that, they controlled for income? Even spelled out that the effect of the ash borer was greater in wealthier regions thanks to the greater amounts of tree cover? Well, what do you know, scientists can sometimes actually know what they're talking about! Shocking, I know.

      Next time, you could even try reading the full paper [researchgate.net] before you comment and call them "amateur scientists." Especially when they, you know, have already thought of everything you've pointed out.

    • Did you read even the summary?

      The most basic would be answering the question -- why are there more trees in a given area?

      Because the pine borer killed them.

      In densely populated urban areas, there will be fewer trees, obviously... and we know cities have more pollution than a prestine wilderness. But that doesn't mean the trees are what's making people healthy... it could just be that the absence of pollution is.

      The areas are the same. They compared before the bugs killed the trees to after. Human health declined with the trees. Again, same areas. Presumably the bugs didn't move in and build coal fired power plants.

      This is an incomplete analysis and an attempt by an amateur scientist to start with a conclusion and work his way back to find supporting facts, while ignoring the fact that in science, you do things the other way around. And if you don't, you get crap like this.

      She says, evidently having argued against the title and working back to what the paper must have said rather than reading the paper first. Also, there are seven authors. So not "an amateur scientist" but "seven amateur scientists." N

    • by Wraithlyn (133796)

      It takes a special kind of arrogance to assume these scientists (including the ones that peer reviewed the work for publication) aren't aware that "correlation doesn't prove causation". I mean seriously? You really think nobody thought of this incredibly obvious fact you're pointing out? You think the "after accounting for all variables" right there in the summary, means absolutely nothing at all?

      As others (like Baloroth below) have pointed out, you clearly HAVEN'T "taken a good look" at the study, and t

    • by gr8_phk (621180)

      You have to control for human behavior in this, or your analysis is broken.

      Not so much. The data was taken by county. Not sure how many were used but there are over 3000 in the US. The affected states contain people of diverse types and so do the unaffected states. They also included data from before and after the ash borer invasion. So unless there is some interesting human behavior that changed in those states over those years, it should not contribute to the conclusion (meaning it is ruled out).

    • Take a good look guys. This guy just committed a basic mistake in method. He made a leap unsupported by the facts. The presence and quantity of trees may be correlated with healthier people, but that in no way means there's a connection.

      Maybe you should try checking for a claim of causation before trotting out the lame correlation != causation cliche. The title of this fine summary is: "Death of Trees Correlated With Human Cardiovascular & Respiratory Disease"
    • Take a look, girl. I'm not sure who "This guy" is.. The study was authored by seven people, six of whom have doctoral degrees. But I'm sure you've outsmarted all of them...
  • by GodfatherofSoul (174979) on Tuesday June 11, 2013 @03:09PM (#43977047)

    Suck it!

  • M. Knight Shyamalan was on to something.

    But seriously, it's no wonder places like The Stanley Hotel are still popular. After Stanley went to the area to recover from TB (with all that repertory jazz) it turned out to be such a good spot, he opened a hotel. It couldn't have been just the crisp air. Maybe we should have neighborhood tree planting campaigns alongside the neighborhood watch.

    • by Nidi62 (1525137)

      But seriously, it's no wonder places like The Stanley Hotel are still popular.

      It also helps that the hotel was the basis for a very popular Stephen King book and movie, or that it sits in the middle of a beautiful national park.

      • by pspahn (1175617)

        It also helps that the hotel was the basis for a very popular Stephen King book and movie

        The exterior images of which were shot on Mt Hood in Oregon. The actual Stanley hotel does not resemble anything in the movie much at all.

        or that it sits in the middle of a beautiful national park.

        ...a park where tens of millions of trees have died in the last several years due to insects.

        • by Nidi62 (1525137)

          It also helps that the hotel was the basis for a very popular Stephen King book and movie

          The exterior images of which were shot on Mt Hood in Oregon. The actual Stanley hotel does not resemble anything in the movie much at all.

          Physically no, you are correct. However the story itself was based on that hotel. I don't know about you, but I'd rather stay in the hotel the one in The Shining was based on, not where they did the exterior shots. One of the stories is that Jim Carey couldn't even stay one whole night in the room that is supposed to be most active.

          • by pspahn (1175617)
            Room 217 I believe. We knocked on that door once when I was younger. The maid answered and didn't speak much English. I wasn't too scared, and in fact it kind of cheapened the whole mystique of the room.
  • Is this a surprise? We evolved in nature - with trees. Even now, we still do not know how much effect long term presence or absence of many trace compounds has. Whether it is something found in diet, or even in the air, emitted by plant transpiration. To think we do, and have it all under our thumb is simply hubris, and it will bite back.
    • I think it's simple. Trees are relaxing. Less stress makes your health better.

      Did you ever notice that everything in Lord of the Rings that kills trees is evil?

      JRR was on to something.

    • Plot lifespan of the human race over the last 1000 years against the estimated number of trees. Tell me what corralation you find.
  • The magnitude of this effect was greater as infestation progressed and in counties with above-average median household income.

    lol so nothing to do with trees. Wealthy people have cardiovascular disease and the problem has increased over time.

  • by Stumbles (602007)
    Pardon me while I pull something out a my ass.
  • To repeat what others have said, correlation doesn't necessarily mean causation. More people have moved to cities too, where the air is worse. And no one is able to "account for all variables".
    • by sjames (1099)

      It does however glance over at it while waggling it's eyebrows meaningfully.

  • It's not April 1, but perhaps they just overslept?

  • I have lived for 20 years in an established Midwestern suburban area (all major residential developments are 50-120 years old) where the Emerald Ash Borer has just begun to take its toll. Aside from the green ash (a frequently-planted street tree) we have blue, black and white ash, all native to the area in fair numbers. I walk a lot in my neighborhood. I know individual trees, and I notice when one is gone. I really noticed the one morning this spring when eight were gone in one day along my mile-long walk

  • by dkleinsc (563838) on Tuesday June 11, 2013 @03:51PM (#43977547) Homepage

    "Well my basic hypothesis was that trees improve people's health."

    There's no particular reason why that hypothesis would be true. And I say that as someone who enjoys walking around in the woods. In fact, for those with nasty allergies, trees can be positively bad for your health.

    I'd want Mr Donovan to produce, at the very least, some sort of proposed mechanism behind "trees => health".

    • Re: (Score:2, Insightful)

      by Anonymous Coward

      Trees are linked with localized reduce wind, reduce pollutants, increase oxygen, increase biodiversity, and partially regulate local temperature year round. There is just as much to assume that his idea is correct as it isn't. Thus why testing is needed and why his idea is called a hypothesis.

      I can't believe you are criticizing someone for doing science by stating that the premise hypothesis is not proven already. Do you always criticize things that are not tautologies?

      • by dkleinsc (563838)

        With the exception of reducing pollutants and increasing oxygen, what do any of those have to do with human health? Humans can be reasonably healthy in high-wind, low-biodiversity, temperature-volatile environments.

        My criticism is not "All hypotheses are dumb". It's more of "Hypotheses should be the product of observation and educated guessing, rather than wild guessing." Otherwise, you spend a lot of time and effort testing stupid hypotheses.

    • by gr8_phk (621180)

      There's no particular reason why that hypothesis would be true. And I say that as someone who enjoys walking around in the woods. In fact, for those with nasty allergies, trees can be positively bad for your health.

      Wow you're stupid. [google.com] Even if you don't want to sift through all those results and evaluate their validity, that widely held belief should be reason enough to start with that hypothesis.

  • TFA has it exactly backwards -- The rise in tree deaths is clearly directly related to the rise in obesity in the study area, which has led to an increase in the average weight of persons newly buried in local cemeteries, which results in higher outgassing of carbon and other greenhouse gases from tombs and mausoleums. Humans are the cause of everything horrible on this planet, didn't you get the memo? Especially the SUV drivers, they're overplusdouble evil.
    • by Hartree (191324)

      Wait a minute. I'm an overweight SUV driver.

      Cool! I must be getting double vengeance on all the Japanese Lilac trees here that are blooming and making me sneeze and wheeze!

  • For all those cardiovascular and lower respiratory disease deaths?

    So a proper, well-balanced experiment would be for us to destroy 100 million trees somewhere NOT infected with emerald tree borers, and see what happens to the human death rate then, eh?

    Hey, it's tough on the trees, I know .. but in the end .. if it WERE all the fault of the emerald tree borer, humans might do more to protect the trees while protecting themselves! Seems, fair, right?

    Man, ain't the scientific process wunnerful?

  • Or a desert state? These places should stand out like sore thumbs. But Colorado - far from a forested state enjoys some of the best health and lowest cancer rates even though there is increased background radiation from the mountains.

  • Now we know which plane Mourns-For-Trees comes from.
  • They have it backwards... as humans get unhealthier, the trees suffer.

    So exercise and eat right... remember for every mile you jog, you save a tree!

  • If you're the one cutting the trees down, that's good physical exercise so you'll probably have better heart health and respiratory capabilities.

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