A Light in the Forest

One freezing day in February 2006, physicist Andreas Mershin huddled with others around a tree on the Massachusetts Institute of Technology campus to watch an unlikely demonstration. An engineering company claimed it could produce electricity simply by wiring a nail in the tree’s trunk to a metal rod in the ground. Sure enough, the demo worked—but nobody knew exactly why.

Two years later, Mershin and MIT undergraduate Christopher Love have not only figured out the source of the tree’s electricity, they’ve joined a new company—Voltree Power—that wants to use that energy to power wireless networks of environmental sensors.

As reported in PLoS ONE, the electricity stems from an acidity difference between trees and soil. The area that is more acidic contains a higher concentration of positively charged hydrogen ions. Those ions attract electrons, generating a tiny current that travels between the tree and the ground.

Using a device that extends probes underground, Voltree’s invention harvests the energy and uses it to continuously recharge a battery, which in turn powers radio-equipped sensors. Voltree is now working to assemble a wildfire alert network that can feed sensor data to a central location. The devices could also monitor climate conditions or even detect illegal radioactive materials at the border.

While other monitoring tools have been hampered by the need for costly solar panels or frequent battery replacements, tree-powered sensors could be deployed over vast areas with little maintenance. And not to worry, Mershin says: the amount of energy harvested is so tiny that the trees won’t feel a thing.❧

—Roberta Kwok

image:      ©Tim Robberts/Stone/Getty Images

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12 Comments

  • The Conservationist » Tapping Trees For Electricity Not A Good Idea April 29, 2009 at 4:18 pm

    […] current issue of Conservation Magazine has an interesting article about an engineering company that has come up with a way to extract electricity from trees.  The […]

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  • Wizo May 21, 2009 at 1:13 am

    this is a good thing. It will also slow the harvest of old growth trees hopefully. You know nails and loggers don’t mix. I read an article that the nails injure trees, but i believe that the author is ignoring that some people have been known to spike a tree to prevent harvesting.

    Reply

  • Chris May 25, 2009 at 11:48 pm

    I’m just worried about when this becomes widespread and common. Continuous liberation of the energy of the electrons involved may lead to some rather spectacular lightning shows =/ Anyone see any reason why not?

    Reply

  • Steven Earl Salmony May 26, 2009 at 9:31 am

    If we do not have broad and open discussions like this one, how on Earth are we going to avoid a distinct possibility: that humans seem destined, despite our intelligence, to play out a scenario of reproduction that is much like that of other species. We know better.

    It appears that humans not only know better, we will not have the chance to do what we know if leaders in my not-so-great generation of elders continue to treat certain vital topics as a taboo.

    We have many leaders with ubiquitous opportunities to speak what is true to them, whatever that may be, regardless of what is politically convenient, economic expedient, social agreeable, religiously tolerable and, therefore, in one way or another culturally prescibed. The leaders of recent years have been doing as they have because they have not possessed a fundamental appreciation for either intellectual honesty or scientific facts.

    In science, there is no place for people who pose as hysterically blind or willfully deaf; posture as if electively mute; discredit or misrepresent good evidence; create the illusion of serious debate; manufacture controversy; and spread uncertainty where none would otherwise exist. Science is an honest and straightforward presentation of carefully and skillfully obtained evidence using scientific principles and methods and nothing more.

    Scientific research is supposed to be done independent from political, legal, economic, social and religious considerations. All of these “considerations” can give rise, either singularly or in combination, to what is called “cultural bias” in science. Unfortunately, the phenomenon of cultural bias that has led many of our brothers and sisters inside and outside the community of scientists to extensively research, widely share and consensually validate factoids based upon faulty reasoning, contrived logic, inadequate theory and mountains of unsufficiently understood data.

    Scientific facts need to be adequately and more accurately distinguished from politically convenient and economically expedient, preternatural factoids.

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  • mrhassell June 1, 2009 at 11:47 pm

    Wizo – Picking up your point re; Tree Spiking. I’m sure this does impose some transfer of a negative against the organic structure!

    http://en.wikipedia.org/wiki/Tree_spiking

    This article more specifically is in relation to the xylem of a potted ficus benjamina tree and it’s Soil. Being that it is in a pot, I’m not so sure that Tree Spiking is relevant.

    The original document is really quite a wonderful read and I recommend that you zip over and check it.

    http://www.plosone.org/article/info:doi/10.1371/journal.pone.0002963

    Reply

  • Olivia June 9, 2009 at 7:59 pm

    how does any human know what a tree feels? hammer a nail into your leg and if I cannot hear you may I assume that you do “not feel a thing”? oh well, they are “only” trees.
    If life is sacred are we only speaking of human life?

    Reply

  • Mary Turner June 29, 2009 at 11:26 am

    Extracting electricity from trees, I feel a need to again to speak up. Every thing we do has consequences. When I was a child true I thought as a child. And when I became adult I am expected to behave as one. True, tree are alive and they do create electricity only a small portion. Right now we need, play the catch up game and replace the multitude of trees that have already been slaughtered due to the concrete masters. Yes, tree’s have feelings, observe the unkempt tree. See how it erects itself its branches how they speak to the heavens, the way it moves showing off its beauty saying,see me. Their purpose to cool and provide and filter free air and not to mention its medicinal purposes. There is still much more, it is obvious we do not appreciated our tree see the rate they are cut down always for a purpose. For now use tree for electricity, should be a last resort last resort. A decade ago, a lone tree sheltered me from the sun, and it breath on me it gave me just what I needed what little sweat I had on my body cooled me. We must give more thought to what we do. I have much more to say about this matter. Science is good for now lets do damage control. In closing electricity from trees is a good idea but it will only supply a small portion of our need I understand we are running out of oil… We must to grow more tree’s. I like what California has done. This is a friendly opinion, yes we are all in this together.

    Mary

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  • Emerald September 5, 2009 at 4:03 pm

    @ Olivia: While I can appreciate the sentiment that all forms of life should be respected, protected and cherished, I think it goes a bit too far to condemn this kind of progress in light of far more destructive methods currently being used to feed our energy needs.

    How do we know the ground doesn’t scream when we walk on it? That trees didn’t cry when our ancestors cut them down to build shelters for themselves, leading the way to our current societies? That the roots severed to make way for the power-supplying pole currently feeding your internet connection didn’t feel the pain?

    Unless you’re content to stand still and cease consuming anything, you’re going to leave marks everywhere you go. This is an excellent example of how to be as lease destructive as possible, far and away a massive improvement over the strip mining seen all too recently in our history. I could say ‘would you prefer we all went back to caveman days and consumed next to no energy?’, but then of course you would have to chop down trees and burn them.

    Reply

  • D. Pham October 6, 2009 at 9:10 pm

    This book is really an interesting piece to add to your collection. I was disappointed at the movie, but overall the book has what most 7-8th grade teachers need to incorporate the standards within the book.

    An essay of this book can be found at:
    http://bookstove.com/drama/light-in-the-forest/

    Reply

  • Lejoie March 17, 2010 at 4:34 pm

    Technology for use in conservation is great, can’t wait to see what else these geniuses at MIT think up next. To conserve and protect should be our motto as environmental police. Earth Rights for all!

    Reply

  • Ikkonoishi April 12, 2010 at 9:50 pm

    @Steven Earl Salmony
    Nice copypasta spammer. http://www.google.com/search?q=%22If+we+do+not+have+broad+and+open%22&filter=0 Why not just start a blog, and make posts about articles that interest you? The linkbacks will link to your page then, and at least you won’t seem so offtopic all the time.

    Reply

  • ChayD July 24, 2010 at 7:46 pm

    I’d be a bit concerned that that potential difference is there for a reason, and perhaps imbalancing it would damage the tree’s growth or overall health. I would hope that they do some research on these possible effects before deploying this further.

    [WORDPRESS HASHCASH] The poster sent us ‘0 which is not a hashcash value.

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