Exploring How and Why Trees ‘Talk’ to Each Other
e360.yale.edu
e360.yale.edu
"The fungus not only penetrates and envelops the tree's roots, but also allows its web to roam through the surrounding forest floor. In so doing, it extends the reach of the tree's own roots as the web grows out toward other trees. Here, it connects with other trees' fungal partners and roots. And so a network is created, and now it's easy for the trees to exchange vital nutrients and even information--such as an impending insect attack" (51).
I look at groups of trees, and trees in general, very differently than I had before I read this book. I'm happy to see this Yale article make it to HN.
As someone who has a passing interest in mycology I find this as much interesting in how important fungi is to the world as are trees. It has many proponents who believe fungi doesn't get enough credit for fueling the world's ecology as plants and trees. Possibly due to mushrooms perception as being harmful to humans.
Thanks for the book recommendation (Amazon link https://www.amazon.com/Hidden-Life-Trees-Communicate-Discove...).
Instead of "talking" - communicating
Instead of "feeling" - sensing
Instead of "thinking" - processing
And so on. We risk anthropomorphizing other living beings we can't possibly relate to. Just as it's important we gain better understanding of how other living things live, it's just as important to not apply how we live to them.
At worst we should talk about "analogs" instead of euphemisms. Does a tree feel "pain" or does a tree feel a "pain analog"? The first is ascribing something that may not even make sense, the second grounds us in comparisons and looking for cause and effect analogs.
Do trees talk? No, they have no mouths. Do trees communicate? As we understand these things more and more, it appears that there's some kind of analog there.
Do trees feel? Maybe that's the wrong question. Do trees respond to stimuli? Of course!
But the breakdown is a good one.
It also brings to mind the trivium from the mediaeval academic curriculum: grammar, logic, and rhetoric.
Grammar is the process of acquiring (and making sense of) information.
Logic is the process of interpreting and processing information.
Rhetoric is the process of transmitting information.
Or: it's an input, logic, output sequence.
This can be applied to much of information-systems or information-theory work. Perhaps with the addition of some endogenous or exogenous information storage and retrieval system.
As for talking: the deaf speak, with their hands.
Symbolic representative abstract communication is just that. I'd argue that the relevant element of talking is the interactivity of the conversation.
Take the old Unix "talk" command. It was contrasted to "write", "wall", or "mail", in that both parties could talk at the same time.
Myself and my girlfriend, 800 km apart. That in the 1980s was mind-blowing. And much cheaper than long-distance telephony.
> That’s how we came up with the term “mother tree,” because they’re the biggest, oldest trees, and we know that they can nurture their own kin.
the interview doesn't reference any work that specifically states these mother trees will preferentially nurture kin over other species. For example, when she describes the more controlled greenhouse experiment with Douglas firs and Ponderosa pines, an injured mother tree Douglas fir dumped carbon into the network and the ponderosa pines still absorbed it. She may have other work that describes some kind of kin preference, but I don't see it cited and I don't quite understand what the mechanism to make this happen would be.
Rather, (as a layman without any knowledge of the work and published papers around this topic), I see this phenomenon not as the result of "mother trees" but from "farmer fungi." The fungi, because of their large networks and relationships with the trees, become "resource managers" of the forest. The fungi have an incentive to make sure that the trees are healthy and will continue to provide nutrients for the fungi. When younger trees are injured, that is a threat to the fungi's survival, and therefore one possibility is that they have evolved this mechanism that transports resources from older trees to the younger ones to help the younger trees survive. The relationship between these fungi and trees are normally symbiotic, but the older trees "tolerate" (or fail to evolve some immune response to) this mildly pathogenic behavior because it likely benefits its nearby offspring or close kin.
I think the concept of the "mother tree" might be slightly anthropomorphic, assuming that a large, multi-organ plant must be more intelligent and possibly be even more caring than small fungi that must only be able to perform simple functions. In reality, the fungi are the organisms in the best position to evolve this beneficial behavior.
Again, I'm a non-expert with zero knowledge on this topic. If anyone could provide a reference to a free online paper that describes these "mother trees" as preferentially nurturing kin, I could be persuaded. And that would be a very interesting read!
> In later experiments, we’ve been pursuing whether these older trees can recognize kin, whether the seedling that are regenerating around them are of the same kin, whether they’re offspring or not, and whether they can favor those seedlings — and we found that they can. That’s how we came up with the term “mother tree,” because they’re the biggest, oldest trees, and we know that they can nurture their own kin.
It seems that Kevin Beiler was the one who did research about this so that may be a good place to start rather than the author.
But whenever reading something like this quote below, where it's clearly a useful narrative for funding and public support, I find it's always good to be skeptical about how far that analogy extends:
> We’ve got a lot of interest from First Nations groups in British Columbia because this idea of mother trees and the nurturing of new generations very much fits with First Nations’ world view.
>The relatedness of neighbours in mono-specific plant communities can also influence whether MNs will elicit adaptive behavioural changes. For example, foliar nutrition in AMF Ambrosia artisifolia L. improved when it was integrated into an MN with related plants but not conspecific strangers (File et al. 2012). Likewise, in mono-specific pairs of EMF interior Douglas-fir grown in greenhouse conditions, foliar micronutrients were increased in kin compared with strangers grown with older conspecifics (Asay 2013). This appears to be linked with mycorrhizal association of this system as mycorrhizal colonization was also elevated in kin seedlings (File et al. 2012; Asay 2013). These findings reveal that MNs can play an integral role in kin selection, but the exact mechanisms by which they do this are unclear. However, there is strong evidence that biochemical signals derived from mycorrhizas or roots are involved. For example, Semchenko et al. (2014) showed that root exudates carried specific information about the genetic relatedness, population origin and species identity of neighbours, and locally applied exudates triggered different root behaviour responses of neighbours. This included increased root density, achieved through changes in morphology rather than biomass allocation, suggesting the plants limited the energetic cost of their behaviour.
>Because the overwhelming majority of plants are predominantly mycorrhizal in situ, any root exudates involved in kin recognition are likely to be filtered through mycorrhizal fungi. In a recent study using stable-isotope probing, we found that MNs transmitted more carbon from older ‘donor’ Douglas-fir seedlings to the roots of younger kin ‘receiver’ seedlings than to stranger ‘receiver’ seedlings, suggesting a fitness advantage to genetically related neighbours (Pickles et al. unpubl.). ...
An additional selection process could be as simple as spatial proximity. Daughter trees are more likely to germinate close to their mother, and the mycorrhizal network can be expected to conserve energy by transporting nutrients no farther than needed.
Besides that, there's other evidence of kin selection in plants, in the form of reduced root competition. http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.12121/p...
But there's a broader point here. You're reading the word "mothering" narrowly, only w/r/t/ the selection of individual organisms. But selection can also take place on the whole plant community. Eugene Odum, widely considered the father of ecology, points this out: https://www.youtube.com/watch?v=6P9V6h2z79w&t=3m15s Plants can't get up and walk away, and polyculture plant communities are healthier than monocultures. So I would argue that even in the hypothetical absence of kin selection, "mothering" could take the form of encouraging a diversity of species in a tree's immediate surroundings, making a favorable local environment for their offspring.
I thought the sentences following your second quotation from the first paper, hypothesizing on the mechanism for kin selection, to be quite interesting:
> This may have been facilitated by the greater mycorrhizal colonization of kin than stranger seedlings (Asay 2013), creating a stronger sink in the MN, an effect also noted in the study by File et al. (2012). The greater colonization of kin seedlings may have arisen from complimentary genetics of the fungal genet and tree genotype (e.g. Rosado et al. 1994a, b). [...]although the mechanism through which the MN elicits the behavior response remains to be resolved.
This genetic mechanism makes sense to me.
The first paper talks about many rich, complex relationships. Two topics I thought were very interesting:
> A fungus can express a mutualism with one plant, while simultaneously exploiting a different plant. Mycoheterotrophic plants are perhaps the most extreme example of this type of exploitation, where a plant acquires all of its carbon by parasitizing fungi through the MN (e.g. Leake 1994; Massicotte et al. 2012). These plants link into the MN of a nearby tree and siphon off photosynthate, enabling them to survive and grow. Importantly this reveals the existence of a mechanism by which plants can acquire nutritional levels of carbon from mycorrhizal fungi. The fitness of all participants in this scenario is increased by the existence of the MN: (i) the mycorrhizal fungus acquires carbon from the tree (or multiple trees) and may use the mycoheterotroph as the staging ground for long-distance exploration and colonization, (ii) the mycoheterotroph acquires carbon from the fungus and (iii) the tree gains access to a wider pool of soil resources, and potentially connection to other trees facilitating the detection of defence signals.
> There is evidence for both tit-for-tat and reciprocal altruism in MNs in forests, both which would be resistant to cheaters (i.e. individuals that benefit without reciprocating). Tit-for-tat, distinct from mutualisms, is evident in bidirectional transfer between paper birch and Douglas-fir (Simard et al. 1997a, b; Philip et al. 2010) and between unrelated Douglas-fir (Teste et al. 2010). This cooperative bidirectional exchange occurs over a period of a few days and appears to be related to the behaviour and possibly fitness of the individuals involved in the network. However, reciprocal altruism, or repeated prisoners dilemma, occurs over longer time periods, and this explanation is more congruent with the highly variable disturbances and hiatus in forests. There is some evidence for reciprocal altruism through the switches in the direction of net carbon transfer between paper birch and Douglas-fir (Philip 2006) or maple and trout lily seedlings (Lerat et al. 2002) in response to differential changes in plant phenology over a period of several months.
Your second paper on kin selection appears to be mainly theoretical on the topic of competition theory, not an observational study of plants or fungi. It makes weak conclusions like "It is reasonable to hypothesize that traits expressed only in the presence of strangers may indicate competition or selfishness, while traits expressed in the presence of kin may indicate cooperation or altruism (Murphy & Dudley 2009; File et al. 2012)" and "It is too soon to know if plant kin recognition responses will demonstrate the breadth that has been found for kin selection in animal behaviour."
> But selection can also take place on the whole plant community.
No doubt.
PBS's Nature did a whole documentary on plant behavior, which includes the author of that study: https://www.youtube.com/watch?v=CrrSAc-vjG4&t=38m00s
As we start to approach a true AI, I have a feeling a side effect will begin to understand there multiple sentient organisms we simply dismissed due to _some_ standard.
Much like how earth retreated from the center of the universe, to just a wet rock orbiting a slightly above average brightness yellow dwarf.
Blind humans cannot recognize themselves in a mirror either, but it doesn't mean anything about their sentience.
I was just reading about Muir and his communication with the living Nature around him. This isn't "mystic" mumbo-jumbo: many of the chemicals being used in these tree+fungus networks are also used in our "internal" systems. We speak tree on the chemical level.
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I want to report on some events in a backyard here in San Francisco.
The western part of the city, from Twin Peaks to the ocean, is mostly built on sand. Before the houses were there it was scrub and beach for more than a mile.
The backyard in question consisted of this very sandy soil, with just enough organic matter to bind it a little and turn it tan-brown. Some plants had been set in years earlier, a couple of rose bushes, lilacs, some calla lilies. Grasses and oxalis and some other things were doing their best, but there were patches of bare dirt, and by dirt I mean of course just dirty sand.
So I went to the store and got a bunch of bags of organic hummus/mulch and just plastered every open space with it an inch thick. It was rife with mycelium and the fungus lost no time in binding and sealing itself together in a single mass over the sandy soil. Realizing this I made sure to connect all the patches together by thick bands of mulch so the whole yard could communicate.
The specific thing I want to mention is this: After a few weeks, maybe less, I was watering a patch of the mycelium mulch one day when I stopped and stuck my finger into the ground to check absorption depth. While the surface was completely wet, even drenched, imagine my astonishment when I found that just under the surface less than a quarter of an inch down it was bone dry.
I watered that patch for a solid minute until puddles has formed in every slight depression. Still it was completely dry just under the surface. But the puddles vanished in seconds!
I watered it again, just dumping water on it from the hose. A certain amount would puddle up, but the bulk of the water simply vanished. Gallons of water and still the soil was bone dry just below the wetted top layer.
I poked around a bit more and found that the mulch had become nearly solid mycelium bound around the little wood chips and other media in it. It had a glossy sheen and was forming a sort of sheet or membrane rather than just strands. The point is: that fungus had sealed the water off from the sandy very-high-drainage dirt underneath and was channeling it somewhere.
There is much still to learn about how Nature works.
Social anarchist and proponent of ecological anarchism Murray Bookchin has written about the challenges facing our current society and indeed produced by it with regard to the earth's ecology. He writes,
>Social ecology is based on the conviction that nearly all of our present ecological problems originate in deep-seated social problems. It follows, from this view, that these ecological problems cannot be understood, let alone solved, without a careful understanding of our existing society and the irrationalities that dominate it. To make this point more concrete: economic, ethnic, cultural, and gender conflicts, among many others, lie at the core of the most serious ecological dislocations we face today—apart, to be sure, from those that are produced by natural catastrophes.
Although I haven't started to read anything about his social ecological theories, I have found him to be a good writer even if I do not completely agree with him. I thought you would be interested. There's a bibliography on his Wikipedia page: https://en.wikipedia.org/wiki/Murray_Bookchin#Selected_bibli...
I really liked "The Ecology of Commerce" by Paul Hawken http://www.ecobooks.com/books/ecommerc.htm
To my mind it's well established that any political system that is out of harmony with Nature fails eventually. Contrary-wise, ecological sanity is a necessary (but perhaps not sufficient) condition for any political system to succeed.
I dream of buying a large piece of land and living more-or-less in Nature, but I also want to be able to call the sheriff or the ambulance for help if I really need them, so I can't be completely immune to political considerations.
As a thought experiment, I've tried to come up with a "Minimum Viable Civilization"...
Pretend for a moment that you didn't like anything about modern civilization and you wanted to go back to a neolithic existence. This isn't a stable state though: after thousands of years people would forget about how bad things were and start civilization over again. Put another way, it happened once, so what would prevent it from happening again?
So we can't just set the clock back to an earlier idealized age. (Not least because it would imply the deaths of billions of people who are today dependent on the existing system.) Somebody somewhere would eventually rediscover steam power and the feedback loop would begin all over again.
So we are stuck with it, and by "it" I mean technology. At the level I'm talking about the details of the civilization hardly matter, it's the technology that defines our ability to even contemplate living not-in-harmony with Nature.
The Neolithic hunter-gatherer has a pretty sophisticated science and technology for dwelling in the way they do: it is becoming more and more widely recognized that such folk affect and adapt their habitat over time, in effect gardening their world.
But they don't build skyscrapers, they don't launch rockets.
What is the essential difference between the technology of long-term ecologically sustainable hunter-gatherer societies and the modern technology we take for granted today?
Two things: Power, and motive.
Power, capacity to do work, I don't need to define. We burn trees, fresh or as petrol, and eventually we harness the atom. Power is an unqualified good. It has to be used wisely. (Ask the Aral Sea what happens if you fail.)
Motive on the other hand can be good or bad. The "motive" of the neolithic society is to carry on in an eternal fashion, part of Nature, and so timeless.
The "motive" of current society, in contrast, is consciously or unconsciously a movement from "the past" to "the future" which by definition is different than now, and better.
Now, obviously, you can't maintain "progress", as it's called, forever. For society to last it has to attain some sort of stable state (even if that "state" is more of a dynamic "strange attractor", like the rise and fall of empires.) On the individual level the psychology of being future-fixated runs counter to the sanity of peace which implies contentment in the here-and-now.
But we do not want to forgo science, nor the obvious benefits that accrue to industrial, scientific technology. (Rockets, computers, materials, medicine, etc.) I don't imagine a world of navel-gazers in stasis.
SO, a Minimum Viable Civilization has to contain the core of our technical know-how, it has to allow for continuation of scientific investigation, and it has to look superficially like a combination of neolithic hunter-gatherers and Jeffersonian agrarian republic (economically if not politically) together in a stable mode: The farmers can't take new land without they leave the old to the wilderness. And the wilderness is actually high-touch horticulture over much of its area, although true wild lands would be set aside (for the spirits and whatnot.)
You would still have your Large Hadron Collider but no plastic in the oceans.
The rest of this is an excerpt from a bit I wrote in 2013, in the context of a "Future History" fictional projection. (I was very encouraged when I saw E. O. Wilson's "Half Earth"!)
In the future the surface of the Earth has been divided into two kinds of zones or areas: "Inside" and "Outside".
Inside: Artificial, Safe, Immortal
There is a single city but it's discontinuous, not connected. It's like islands and archipelagos of built area embedded in a "sea" of wild land and water. The city is ultra-tech, nano and beyond. People there do not age, or age and rejuvenate as they please. All the transhumanist techno-utopian dreams are come to fruition within the City. Barring accidents you live as long as you want and it is Christmas every single day.
Outside: Real, Dangerous, Reproductive
The rest of the world is one giant Nature reserve. All of the oceans and the great majority of the land masses are kept in a Natural state and evolution is permitted to continue without interference from our human institutions within the City. People live Outside too, in tribes and homesteads, and although there is first aid and basic medicine and surgery, they voluntarily endure the "slings and barbs of outrageous fortune". Transhuman modifications and forms are not "worn" Outside. This is also where all new people are conceived, gestated, and born. If you want to have a baby and raise a child you have to go Outside.
This is Humanity's grand compromise with our technology. In order to maintain a normative baseline, a "control group", for our wild forays into the Transhuman realms Inside we have to permit our own natural evolution to proceed Outside.
Graduation
I hadn't figured out what form it would take (it's an ongoing story idea I'm still playing with) but there would be some sort of "intake" or "graduation" process for bringing new humans into the City for the first time. I have no idea, I'm just mentioning it. ^_^
If you hang out with plants and help them then you are a Grower.
If you are making something with your hands that involves protons and neutrons then you are an Artisan.
If you are making something that can be transmitted through photons and electrons then you are a Designer.
If you are helping people to feel better then you are a Healer.
If you are helping people to grow then you are a Teacher.
I think that just leaves Artist and Scientist? I'm going to say that both of those roles are concomitant of the others to a greater or lesser degree per ones own personal tastes and nature.
Grower
Artisan
Designer
Healer
Teacher
Artist
Scientist
As for the structure of the economy I foresee three "levels" or "strata".
The first layer is made up of locally grown and consumed food and other wholesome organic products. On the primary physical level we'll live quite close to the way our "stone-age" ancestors did (and no, billions will not have to perish to let it happen) only with nice houses.
That original organic economy will form the basis or substratum for the other two layers.
There will be an "information" layer where most economic activity takes place that involves people creating wealth in digital form. More than enough has been said about that.
The last layer is relatively sparse and consists of whatever physical transactions are needed to support the two other layers but that are not strictly "of them", meaning non-purely-digital and not ecological or organic. This involves things like extracting particular elements from the Earth for specific experiments and projects.
> In Sweden, scientists studied a spruce that appeared to be about 500 years old. They were surprised to learn that it was growing from a root system that was 9,550 years old.
> In Switzerland, construction workers uncovered stumps of trees that didn’t look very old. Scientists examined them and discovered that they belonged to pines that lived 14,000 years ago. Analyzing the rings of their trunks, they learned that the pines that survived a climate that warmed 42°F, and then cooled about the same amount — in a period of just 30 years! This is the equivalent of our worst-case projections today.
A complex, largely chemically-mediated, environmental-response mechanism. Typically operating at rates far slower than those of animal neurology.
Trees don't have brains: forests are brains.
https://www.ted.com/talks/suzanne_simard_how_trees_talk_to_e...