Sometimes I go
browsing [through] a very old magazine.
I found this observation
test about the story of the ark. And the artist that drew this
observation test did some errors, had some mistakes - there are
more or less 12 mistakes. Some of them are very easy. There is a
funnel, an aerial part, a lamp and clockwork key on the ark.
Some of them are about the animals, the number. But there is a
much more fundamental mistake in the overall story of the ark
that's not reported here. And this problem is: where are the
plants? So now we have God that is going to submerge Earth
permanently or at least for a very long period, and no one is
taking care of plants.
Noah needed to take two of every kind of
bird, of every kind of animal, of every kind of creature that
moves, but no mention about plants. Why?
In another part of the
same story, all the living creatures are just the living
creatures that came out from the ark, so birds, livestock and
wild animals. Plants are not living creatures - this is the
point. That is a point that is not coming out from the Bible,
but it's something that really accompanied humanity.
Let's have a look at this nice code that is coming from a
Renaissance book. Here we have the description of the order of
nature. It's a nice description because it's starting from left
- you have the stones - immediately after the stones, the
plants that are just able to live. We have the animals that are
able to live and to sense, and on the top of the pyramid, there
is the man. This is not the common man.
The "Homo studiosus"
- the studying man. This is quite comforting for people like me
- I'm a professor - this to be over there on the top of creation.
But it's something completely wrong. You know very well about
professors. But it's also wrong about plants, because plants are
not just able to live; they are able to sense.
They are much
more sophisticated in sensing than animals. Just to give you an
example, every single root apex is able to detect and to monitor
concurrently and continuously at least 15 different chemical and
physical parameters. And they also are able to show and to
exhibit such a wonderful and complex behavior that can be
described just with the term of intelligence.
Well, but this is
something - this underestimation of plants is something that is
always with us.
Let's have a look at this short movie now. We have David
Attenborough. Now David Attenborough is really a plant lover; he
did some of the most beautiful movies about plant behavior. Now,
when he speaks about plants, everything is correct. When he
speaks about animals, [he] tends to remove the fact that plants
The blue whale, the biggest creature that exists on the
planet - that is wrong, completely wrong. The blue whale, it's
a dwarf if compared with the real biggest creature that exists
on the planet - that is, this wonderful, magnificent
Sequoiadendron giganteum. (Applause)
And this is a living
organism that has a mass of at least 2,000 tons.
Now, the story
that plants are some low-level organisms has been formalized
many times ago by Aristotle, that in "De Anima" - that is a
very influential book for the Western civilization - wrote that
the plants are on the edge between living and not living. They
have just a kind of very low-level soul.
It's called the
vegetative soul, because they lack movement, and so they don't
need to sense. Let's see.
Okay, some of the movements of the plants are very well-known.
This is a very fast movement. This is a Dionaea, a Venus fly
trap hunting snails - sorry for the snail. This has been
something that has been refused for centuries, despite the
evidence. No one can say that the plants were able to eat an
animal, because it was against the order of nature.
are also able to show a lot of movement. Some of them are very
well known, like the flowering. It's just a question to use some
techniques like the time lapse. Some of them are much more
sophisticated. Look at this young bean that is moving to catch
the light every time. And it's really so graceful; it's like a
They are also able to play
- they are really
playing. These are young sunflowers, and what they are doing
cannot be described with any other terms than playing. They are
training themselves, as many young animals do, to the adult life
where they will be called to track the sun all the day.
able to respond to gravity, of course, so the shoots are growing
against the vector of gravity and the roots toward the vector of
gravity. But they are also able to sleep. This is one, Mimosa pudica. So during the night, they curl the leaves and reduce the
movement, and during the day, you have the opening of the leaves
- there is much more movement.
This is interesting because this
sleeping machinery, it's perfectly conserved. It's the same in
plants, in insects and in animals. And so if you need to study
this sleeping problem, it's easy to study on plants, for
example, than in animals and it's much more easy even ethically.
It's a kind of vegetarian experimentation.
Plants are even able to communicate - they are extraordinary
communicators. They communicate with other plants. They are able
to distinguish kin and non-kin. They communicate with plants of
other species and they communicate with animals by producing
chemical volatiles, for example, during the pollination.
with the pollination, it's a very serious issue for plants,
because they move the pollen from one flower to the other, yet
they cannot move from one flower to the other. So they need a
vector - and this vector, it's normally an animal. Many insects
have been used by plants as vectors for the transport of the
pollination, but not just insects; even birds, reptiles, and
mammals like bats rats are normally used for the transportation
of the pollen. This is a serious business.
We have the plants
that are giving to the animals a kind of sweet substance - very
energizing - having in change this transportation of the
pollen. But some plants are manipulating animals, like in the
case of orchids that promise sex and nectar and give in change
nothing for the transportation of the pollen.
Now, there is a big problem behind all this behavior that we
have seen. How is it possible to do this without a brain? We
need to wait until 1880, when this big man,
publishes a wonderful, astonishing book that starts a
The title is "The Power of Movement in Plants."
one was allowed to speak about movement in plants before Charles
Darwin. In his book, assisted by his son, Francis - who was the
first professor of plant physiology in the world, in Cambridge - they took into consideration every single movement for 500
pages. And in the last paragraph of the book, it's a kind of
stylistic mark, because normally Charles Darwin stored, in the
last paragraph of a book, the most important message.
"It's hardly an exaggeration to say that the tip of the
radical acts like the brain of one of the lower animals."
is not a metaphor. He wrote some very interesting letters to one
of his friends who was J.D. Hooker, or at that time, president
of the Royal Society, so the maximum scientific authority in
Britain speaking about the brain in the plants.
Now, this is a root apex growing against a slope. So you can
recognize this kind of movement, the same movement that worms,
snakes and every animal that are moving on the ground without
legs is able to display. And it's not an easy movement because,
to have this kind of movement, you need to move different
regions of the root and to synchronize these different regions
without having a brain.
So we studied the root apex and we found
that there is a specific region that is here, depicted in blue - that is called the "transition zone." And this region, it's a
very small region - it's less than one millimeter. And in this
small region you have the highest consumption of oxygen in the
plants and more important, you have these kinds of signals here.
The signals that you are seeing here are action potential, are
the same signals that the neurons of my brain, of our brain, use
to exchange information. Now we know that a root apex has just a
few hundred cells that show this kind of feature, but we know
how big the root apparatus of a small plant, like a plant of
rye. We have almost 14 million roots.
We have 11 and a half
million root apex and a total length of 600 or more kilometers
and a very high surface area.
Now let's imagine that each single root apex is working in
network with all the others. Here were have on the left, the
Internet and on the right, the root apparatus. They work in the
same way. They are a network of small computing machines,
working in networks.
And why are they so similar? Because they
evolved for the same reason: to survive predation. They work in
the same way. So you can remove 90 percent of the root apparatus
and the plants [continue] to work. You can remove 90 percent of
the Internet and it is [continuing] to work. So, a suggestion
for the people working with networks: plants are able to give
you good suggestions about how to evolve networks.
And another possibility is a technological possibility. Let's
imagine that we can build robots and robots that are inspired by
plants. Until now, the man was inspired just by man or the
animals in producing a robot. We have the animaloid - and the
normal robots inspired by animals, insectoid, so on. We have the
androids that are inspired by man. But why have we not any
Well, if you want to fly, it's good that you look at
birds - to be inspired by birds. But if you want to explore
soils, or if you want to colonize new territory, to best thing
that you can do is to be inspired by plants that are masters in
doing this. We have another possibility we are working [on] in
our lab, [which] is to build hybrids.
It's much more easy to
build hybrids. Hybrid means it's something that's half living
and half machine. It's much more easy to work with plants than
with animals. They have computing power, they have electrical
signals. The connection with the machine is much more easy, much
more even ethically possible.
And these are three possibilities
that we are working on to build hybrids, driven by algae or by
the leaves at the end, by the most, most powerful parts of the
plants, by the roots.
Well, thank you for your attention. And before I finish, I would
like to reassure that no snails were harmed in making this
walking through a forest.
I'm guessing you're thinking of a
collection of trees, what we foresters call a stand, with their
rugged stems and their beautiful crowns. Yes, trees are the
foundation of forests, but a forest is much more than what you
see, and today I want to change the way you think about forests.
You see, underground there is this other world, a world of
infinite biological pathways that connect trees and allow them
to communicate and allow the forest to behave as though it's a
single organism. It might remind you of a sort of intelligence.
How do I know this? Here's my story. I grew up in the forests of
British Columbia. I used to lay on the forest floor and stare up
at the tree crowns. They were giants. My grandfather was a
giant, too. He was a horse logger, and he used to selectively
cut cedar poles from the inland rainforest. Grandpa taught me
about the quiet and cohesive ways of the woods, and how my
family was knit into it.
So I followed in grandpa's footsteps.
He and I had this curiosity about forests, and my first big
"aha" moment was at the outhouse by our lake. Our poor dog Jigs
had slipped and fallen into the pit. So grandpa ran up with his
shovel to rescue the poor dog. He was down there, swimming in
But as grandpa dug through that forest floor, I became
fascinated with the roots, and under that, what I learned later
was the white mycelium and under that the red and yellow mineral
Eventually, grandpa and I rescued the poor dog, but it
was at that moment that I realized that that palette of roots
and soil was really the foundation of the forest.
And I wanted to know more. So I studied forestry. But soon I
found myself working alongside the powerful people in charge of
the commercial harvest. The extent of the clear-cutting was
alarming, and I soon found myself conflicted by my part in it.
Not only that, the spraying and hacking of the aspens and
birches to make way for the more commercially valuable planted
pines and firs was astounding. It seemed that nothing could stop
this relentless industrial machine.
So I went back to school, and I studied my other world. You see,
scientists had just discovered in the laboratory in vitro that
one pine seedling root could transmit carbon to another pine
seedling root. But this was in the laboratory, and I wondered,
could this happen in real forests? I thought yes.
Trees in real
forests might also share information below ground. But this was
really controversial, and some people thought I was crazy, and I
had a really hard time getting research funding. But I
persevered, and I eventually conducted some experiments deep in
the forest, 25 years ago.
I grew 80 replicates of three species:
paper birch, Douglas fir, and western red cedar. I figured the
birch and the fir would be connected in a belowground web, but
not the cedar. It was in its own other world. And I gathered my
apparatus, and I had no money, so I had to do it on the cheap.
So I went to Canadian Tire --
and I bought some plastic bags and duct tape and shade cloth, a
timer, a paper suit, a respirator. And then I borrowed some
high-tech stuff from my university: a Geiger counter, a
scintillation counter, a mass spectrometer, microscopes.
then I got some really dangerous stuff: syringes full of
radioactive carbon-14 carbon dioxide gas and some high pressure
bottles of the stable isotope carbon-13 carbon dioxide gas. But
I was legally permitted.
Oh, and I forgot some stuff, important stuff: the bug spray, the
bear spray, the filters for my respirator. Oh well.
The first day of the experiment, we got out to our plot and a
grizzly bear and her cub chased us off. And I had no bear spray.
But you know, this is how forest research in Canada goes.
So I came back the next day, and mama grizzly and her cub were
gone. So this time, we really got started, and I pulled on my
white paper suit, I put on my respirator, and then I put the
plastic bags over my trees. I got my giant syringes, and I
injected the bags with my tracer isotope carbon dioxide gases,
first the birch.
I injected carbon-14, the radioactive gas, into
the bag of birch. And then for fir, I injected the stable
isotope carbon-13 carbon dioxide gas. I used two isotopes,
because I was wondering whether there was two-way communication
going on between these species. I got to the final bag, the 80th
replicate, and all of a sudden mama grizzly showed up again.
she started to chase me, and I had my syringes above my head,
and I was swatting the mosquitoes, and I jumped into the truck,
and I thought,
"This is why people do lab studies."
I waited an hour. I figured it would take this long for the
trees to suck up the CO2 through photosynthesis, turn it into
sugars, send it down into their roots, and maybe, I
hypothesized, shuttle that carbon belowground to their
neighbors. After the hour was up, I rolled down my window, and I
checked for mama grizzly.
Oh good, she's over there eating her
huckleberries. So I got out of the truck and I got to work. I
went to my first bag with the birch. I pulled the bag off. I ran
my Geiger counter over its leaves. Kkhh! Perfect. The birch had
taken up the radioactive gas. Then the moment of truth. I went
over to the fir tree. I pulled off its bag. I ran the Geiger
counter up its needles, and I heard the most beautiful sound.
It was the sound of birch talking to fir, and birch was
"Hey, can I help you?"
And fir was saying,
you send me some of your carbon? Because somebody threw a shade
cloth over me."
I went up to cedar, and I ran the Geiger counter
over its leaves, and as I suspected, silence. Cedar was in its
own world. It was not connected into the web interlinking birch
I was so excited, I ran from plot to plot and I checked all 80
replicates. The evidence was clear. The C-13 and C-14 was
showing me that paper birch and Douglas fir were in a lively
two-way conversation. It turns out at that time of the year, in
the summer, that birch was sending more carbon to fir than fir
was sending back to birch, especially when the fir was shaded.
And then in later experiments, we found the opposite, that fir
was sending more carbon to birch than birch was sending to fir,
and this was because the fir was still growing while the birch
was leafless. So it turns out the two species were
interdependent, like yin and yang.
And at that moment, everything came into focus for me. I knew I
had found something big, something that would change the way we
look at how trees interact in forests, from not just competitors
but to cooperators. And I had found solid evidence of this
massive belowground communications network, the other world.
Now, I truly hoped and believed that my discovery would change
how we practice forestry, from clear-cutting and herbiciding to
more holistic and sustainable methods, methods that were less
expensive and more practical. What was I thinking? I'll come
back to that.
So how do we do science in complex systems like forests? Well,
as forest scientists, we have to do our research in the forests,
and that's really tough, as I've shown you. And we have to be
really good at running from bears. But mostly, we have to
persevere in spite of all the stuff stacked against us. And we
have to follow our intuition and our experiences and ask really
And then we've got to gather our data and then
go verify. For me, I've conducted and published hundreds of
experiments in the forest. Some of my oldest experimental
plantations are now over 30 years old. You can check them out.
That's how forest science works.
So now I want to talk about the science. How were paper birch
and Douglas fir communicating? Well, it turns out they were
conversing not only in the language of carbon but also nitrogen
and phosphorus and water and defense signals and allele
chemicals and hormones - information.
And you know, I have to
tell you, before me, scientists had thought that this
belowground mutualistic symbiosis called a mycorrhiza was
involved. Mycorrhiza literally means "fungus root." You see
their reproductive organs when you walk through the forest.
The mushrooms, though, are just the tip
of the iceberg, because coming out of those stems are fungal
threads that form a mycelium, and that mycelium infects and
colonizes the roots of all the trees and plants. And where the
fungal cells interact with the root cells, there's a trade of
carbon for nutrients, and that fungus gets those nutrients by
growing through the soil and coating every soil particle.
web is so dense that there can be hundreds of kilometers of
mycelium under a single footstep. And not only that, that
mycelium connects different individuals in the forest,
individuals not only of the same species but between species,
like birch and fir, and it works kind of like the Internet.
You see, like all networks,
mycorrhizal networks have nodes and
links. We made this map by examining the short sequences of DNA
of every tree and every fungal individual in a patch of Douglas
fir forest. In this picture, the circles represent the Douglas
fir, or the nodes, and the lines represent the interlinking
fungal highways, or the links.
The biggest, darkest nodes are the busiest nodes. We call those
hub trees, or more fondly, mother trees, because it turns out
that those hub trees nurture their young, the ones growing in
the understory. And if you can see those yellow dots, those are
the young seedlings that have established within the network of
the old mother trees.
In a single forest, a mother tree can be
connected to hundreds of other trees. And using our isotope
tracers, we have found that mother trees will send their excess
carbon through the mycorrhizal network to the understory
seedlings, and we've associated this with increased seedling
survival by four times.
Now, we know we all favor our own children, and I wondered,
could Douglas fir recognize its own kin, like mama grizzly and
her cub? So we set about an experiment, and we grew mother trees
with kin and stranger's seedlings. And it turns out they do
recognize their kin. Mother trees colonize their kin with bigger
They send them more carbon below ground.
They even reduce their own root competition to make elbow room
for their kids. When mother trees are injured or dying, they
also send messages of wisdom on to the next generation of
So we've used isotope tracing to trace carbon moving
from an injured mother tree down her trunk into the mycorrhizal
network and into her neighboring seedlings, not only carbon but
also defense signals. And these two compounds have increased the
resistance of those seedlings to future stresses. So trees talk.
Through back and forth conversations, they increase the
resilience of the whole community. It probably reminds you of
our own social communities, and our families, well, at least
So let's come back to the initial point. Forests aren't simply
collections of trees, they're complex systems with hubs and
networks that overlap and connect trees and allow them to
communicate, and they provide avenues for feedbacks and
adaptation, and this makes the forest resilient.
there are many hub trees and many overlapping networks. But
they're also vulnerable, vulnerable not only to natural
disturbances like bark beetles that preferentially attack big
old trees but high-grade logging and clear-cut logging. You see,
you can take out one or two hub trees, but there comes a tipping
point, because hub trees are not unlike rivets in an airplane.
You can take out one or two and the plane still flies, but you
take out one too many, or maybe that one holding on the wings,
and the whole system collapses.
So now how are you thinking about forests? Differently?
Cool. I'm glad.
So, remember I said earlier that I hoped that my research, my
discoveries would change the way we practice forestry. Well, I
want to take a check on that 30 years later here in western
This is about 100 kilometers to the west of us, just on the
border of Banff National Park. That's a lot of clear-cuts. It's
not so pristine. In 2014, the World Resources Institute reported
that Canada in the past decade has had the highest forest
disturbance rate of any country worldwide, and I bet you thought
it was Brazil. In Canada, it's 3.6 percent per year.
Now, by my
estimation, that's about four times the rate that is
Now, massive disturbance at this scale is known to affect
hydrological cycles, degrade wildlife habitat, and emit
greenhouse gases back into the atmosphere, which creates more
disturbance and more tree diebacks.
Not only that, we're continuing to plant one or two species and
weed out the aspens and birches. These simplified forests lack
complexity, and they're really vulnerable to infections and
bugs. And as climate changes, this is creating a perfect storm
for extreme events, like the massive mountain pine beetle
outbreak that just swept across North America, or that megafire
in the last couple months in Alberta.
So I want to come back to my final question: instead of
weakening our forests, how can we reinforce them and help them
deal with climate change?
Well, you know, the great thing about
forests as complex systems is they have enormous capacity to
self-heal. In our recent experiments, we found with
patch-cutting and retention of hub trees and regeneration to a
diversity of species and genes and genotypes that these mycorrhizal networks, they recover really rapidly.
So with this
in mind, I want to leave you with four simple solutions. And we
can't kid ourselves that these are too complicated to act on.
First, we all need to get out in the forest. We need to
reestablish local involvement in our own forests. You see, most
of our forests now are managed using a one-size-fits-all
approach, but good forest stewardship requires knowledge of
Second, we need to save our old-growth forests. These are the
repositories of genes and mother trees and mycorrhizal networks.
So this means less cutting. I don't mean no cutting, but less
And third, when we do cut, we need to save the legacies, the
mother trees and networks, and the wood, the genes, so they can
pass their wisdom onto the next generation of trees so they can
withstand the future stresses coming down the road. We need to
And finally, fourthly and finally, we need to regenerate our
forests with a diversity of species and genotypes and structures
by planting and allowing natural regeneration. We have to give
Mother Nature the tools she needs to use her intelligence to
And we need to remember that forests aren't just a
bunch of trees competing with each other, they're supercooperators.
So back to Jigs. Jigs's fall into the outhouse showed me this
other world, and it changed my view of forests. I hope today to
have changed how you think about forests.