Nature's internet: how trees talk to each other in a healthy forest | Suzanne Simard | TEDxSeattle

This fascinating talk presents the scientific research that shows the interconnectedness of life in the forest ecosystem. It takes us beneath the forest floor where we learn how trees are communicating and exchanging resources. Going beyond the simple view of a forest as a resource to be exploited, it presents the forest as a complex network of life. Her examination of the relationships that make up the complexity of nature present compelling support for the idea that “We are all one.”

Suzanne Simard studies the surprising and delicate complexity in nature. Her main focus is on the below-ground fungal networks that connect trees and facilitate underground inter-tree communication and interaction. Her team's analysis revealed that the fungi networks move water, carbon and nutrients such as nitrogen between and among trees as well as across species. The research has demonstrated that these complex, symbiotic networks in our forests -- at the hub of which stand what she calls the "mother trees" -- mimic our own neural and social networks. This groundbreaking work on symbiotic plant communication has far-reaching implications in both the forestry and agricultural industries, in particular concerning sustainable stewardship of forest's and the plant’s resistance to pathogens. She works primarily in forests, but also grasslands, wetlands, tundra and alpine ecosystems.

This talk was given at a TEDx event using the TED conference format but independently organized by a local community. Learn more at http://ted.com/tedx

The Coast Salish people say, "We are one."

[nə́c̓aʔmat ct]

For thousands of years they lived it.

But we didn't pay any attention.

Most of us have forgotten
that we're connected to each other,

and to nature,

that we are one.

But nature is not some separate thing,
but an intimate part of us.

And what we do on this Earth
ripples through our ecosystems,

our web of connections.

Now, the signs are undeniable:

climate change,

species extinctions,

human suffering.

We have forgotten.

But for their faith, the people
are connected through spirit to forests,

and oceans and rivers
and bears and salmon,

the Coast Salish people were ignored.

But truly, it does come down
to a matter of faith,

to trust and respect the relationships
that make up the complexity of nature.

But we said that's unscientific.

Western science
requires exact measurements,

visible proof,

statistics.

But make no mistake,

the Coast Salish people
were deeply scientific.

How else could they have lived here
for over 10,000 years in such prosperity?

In fact, they were more
scientific than we.

For us to look any deeper,
that would have hampered progress.

"There are trees in those forests,
and our buildings need wood,

and our printers need paper.

We need to cut down the forests
and replant those trees."

Now, how do I fit into this?

Well, I come from a family of loggers.

And while my family
was up on the mountainsides

cutting down trees, one here, one there,

I was playing in the forest below,

in the places that are seen and unseen,

in the trees and the logs
and the forest floor.

And I believed that fairies lived there.

And their job was to live in
and protect the forest, just like my job.

But the fairies couldn't save that forest,

and neither could I;
actually, nobody could.

Because the owner of the patch
had to cut it down to feed his family.

And that moment changed me forever.

Actually, it motivated me.

And I went to school to study forestry.

I wanted to understand the mystery
of why forests felt so powerful to me.

I wanted to save forests.

Ironically though, the first job I got
coming out of forestry school

was to mark old growth trees
for clearcutting,

and then to replant those clearcuts
with fast-growing firs and pines,

and to weed out the unwanted species -
the alders, the birches, the aspens.

And you know what?

Well, it's because
we considered them competitors,

interfering with our profits.

And I got pretty good at creating
these shiny new monocultures.

But you know,
the questions kept piling up.

Why was disease spreading
through these plantations?

Why was cutting out birch
making the fir so sick?

And I was also increasingly worried
about the increasing rate of clearcutting.

You see, I'd learned in school
that about a century ago,

that in Canada, in British Columbia,
they developed this cutting plan

to cut down all of the old growth trees
in the working forest.

I knew about it, I'd learned it in school.

But it took me a long time to realize
that the cutting was not going to stop.

Nor the attitude that we could convert
these old growth forests

into nice marketable, neat plantations.

It seemed to me that there was more
to the forest than meets the eye.

So, I returned to graduate school

and I became fascinated
with the underground,

I wanted to understand the mystery of why
these old growth forests were so powerful.

So, I looked at this UK study,

and they were examining seedlings
growing in the laboratory,

and colonized them with this fungus,
a mycorrhizal fungus.

The fungus connected
the seedlings in a web,

and they transmitted carbon
from one seedling to the other.

A mycorrhiza is literally a fungus-root.

In this symbiotic association
the fungus grows through the soil

picking up nutrients and water,
and bringing them back to the plant,

and trading them
for photosynthetic carbon.

It's a symbiotic, mutualistic,
reciprocal relationship.

And most fascinating to me,

these fungi could
connect plants below ground.

So, I wondered, I thought back
to my fir forests, and I wondered,

could the fungi colonizing birch

actually connect with fir and protect it?

So, I did some research,
I wanted to find out.

My first question
came back to that faith thing again.

Even though we can't see it,

could these mycorrhizal fungi
be connecting trees below ground?

Well, it turns out
that they can in real forests.

Using DNA microsatellites,
we uncovered this network

in an old growth Douglas fir forest.

In this picture, these circles
represent Douglas fir trees.

And the bigger and darker the circle,
the bigger and older the tree.

And those small,
light circles in the middle,

those are the seedlings
growing in the understory.

And these lines
that are linking the circles,

those are the interlinking
mycorrhizal fungal highways.

And you'll notice
that the biggest, darkest circles,

the biggest, oldest trees,
are the most highly connected.

So, we call these 'hub trees.'

and later, more fondly,
we started to call them 'mother trees.'

Because as it turns out,
those mother trees

are nurturing the young
seedlings in the understory.

Now, this map is of only two

of what we think are
100 fungal species in the forest.

Could you imagine if we'd been able
to map all 100 species?

Next I wanted to know, what might be
flowing through this network?

Well, it turns out, the very things
that plants need to survive and grow.

Things like carbon,
and nutrients, and water.

So, we use isotopes, carbon isotopes,
and we label plants,

and we were able to see the carbon

transmix back and forth
through this network,

like messages transmitting
through the internet.

And when one seedling is under stress,
if it's small, or shaded,

or nutrient poor, or senescing,
the other plant sends more carbon.

We figured out that it follows
what's called a source-sink gradient.

From a robust source plant
like an illuminated birch tree

to a needful sink plant
like an understory fir tree,

and all this without
harming the source plants.

The next thing we wanted to know was,

so this happens, but what does
it really matter in forests?

Well, it turns out
if you shade one of the plants,

if Douglas fir's shaded in the understory,
birch will send ten percent of its carbon,

and that's a lot of carbon.

That's enough for Douglas fir
actually to make seeds.

Now, we haven't figured out
precisely what the amounts mean,

but we do know that this transfer
increases their survival and growth,

and health of the seedlings
growing in the understory.

Now, I published this work
in some pretty good journals.

This particular article struck a chord.

Lots of people were enthused.

In fact, there is a whole bunch
of new research all around the world

that was inspired by this paper.

But there were also critics
who tried to discredit my work.

In fact, there were
a lot of papers written,

keynote addresses given,

press releases.

And back home,

a professional ethics letter
was actually put on my file.

And my work was called
"a dog's breakfast."

Now, I know that you know
that this kind of intimidation

is actually not that uncommon
with breakthrough science,

especially if it challenges
the status quo.

Knowing this, this didn't stop me.

I knew that my science
was sound and rigorous,

and I knew that one day it could change
the way we view the environment.

So, really motivated,
I returned to my original question,

because I still
hadn't quite answered it yet.

And I wondered,
could these webs, these networks,

serve as more than just avenues
of exchange of carbon and nutrients

and water.

Could a tree
that's under stress, diseased,

actually benefit
from the health of its neighbors?

Could birch be helping fir?

So, I did some more experiments,
and it turns out, it does.

When Douglas fir
is under stress or disease,

it sends warning signals to its neighbors,

and the neighbors respond by increasing
production of their defense enzymes,

and they're more resistant to disease.

And if that neighbor is a birch tree,

the fir benefits from
the antibiotic-producing bacteria

that are associated
with this shared network.

It's like a public immunization system.

And I wondered, could there be more
than defense signals moving?

Well, it turns out that trees
can actually recognize,

transmit messages to their relatives.

A mother tree can recognize
whether seedlings in her neighborhood

are her kin or strangers.

She sends more carbon
to kin seedlings than to strangers.

And if the mother tree is injured,

she sends even more carbon
to her kin seedlings.

It's as though she's passing her energy,
her legacy, to the next generation.

Now, when I look at all this together,

it's as though these trees
are sharing their deepest secrets.

This is breakthrough stuff.

It's pretty exciting.

You know, at the time,
there were actually many articles written,

Popular Science,

documentary films,

the word was getting out,
and I was really, really excited.

But I got cancer.

And that was really awful.

But you know,
the beautiful thing about this

is that it re-connected me with my people.

My people, my family, looked after me.

They held me.

They helped me up the stairs.

They cooked my meals.

They looked after my children.

They saved me.

And back in the hospital,
I made even more connections,

strong ones,

with other women fighting breast cancer.

And we were really afraid,

and we cried.

But we also laughed.

We still do every day.

We've become so tight,
we're like this tapestry

that's knit together in a tight weave.

When one of us stumbles or bends,
the others are right there to pick her up.

What I've learned through all this,

is what my forests
have been trying to tell me all along -

that these connections
are crucial to our well-being.

They're not easily seen,

but they're real.

And you know what? I'm living proof.

And I'm really grateful.

(Applause)

Thank you.

Now that I'm strong and healthy again,
I've returned to my science,

and I'm asking other questions.

My first, and the most important
question to me is,

what can our discoveries tell us
about how to deal with our biggest threat?

Climate change.

Yeah, climate change is no hoax.

In fact, we can't kid ourselves,

there is no fancy engineering
that's going to get us out of this mess.

What my discoveries have shown me,
is that the answer, the solution,

lies in our relationship with nature.

And in doing this research,
I went to the Aboriginal people.

I'm doing my research
with Aboriginal people

who are, as you know,
dependent on the salmon,

have a long relationship
of stewardship of the salmon

which then helps with their livelihood,
it is crucial to their livelihood.

So, in the fall, when the salmon
are spawning in the rivers,

the bears come down to the river,

and the wolves, and they feed
on the salmon in the spawning rivers,

and they carry the salmon
up into the forest.

And underneath the big, old mother trees,

under the sheltering crowns
of the mother trees,

they feed on the salmon.

And in the fall, the leftovers decay
and seep into the ground.

And we think

that the big mycorrhizal networks
of those mother trees

soak up that nitrogen.

And scientists have discovered
traces of salmon nitrogen

in the tree rings,
stored there for centuries.

And what we're going to do this summer
is go back to these forests,

and we're going to trace whether nitrogen
- and we think this is happening -

moves from mother trees
to their neighbors,

from tree to tree to tree,
deep into the forest.

And we think this is tied
to the health of the forest,

which of course is tied
to the health of the rivers,

which of course is linked to the salmon,
and the health of the salmon populations,

which of course, feeds back to the oceans,
and comes back to us, the people.

Now, this circle of life,

what our Aboriginal ancestors
have called 'reciprocity,'

is the trading of mutual respect.

And this is a really good example
of what scientists are calling

'complex adaptive systems.'

Now look, forests
are built on relationships.

In a healthy forest, everything
is connected, and communicating.

Here, these nodes represent the species.

And they're constantly
relating to each other.

And it's out of their interactions
that emerges what scientists are calling

'complex adaptive behaviors,'

or higher system level properties.

Things like resilience and health,

the cycling of clean air and clean water.

But you know, in modern society,
we view ourselves separate from this,

somehow entitled, or superior,

or at the minimum, we take it for granted.

But the thing is,
when we take out key parts,

like the grizzly bears,

and we trash the salmon populations,

these systems rapidly degrade

into what we're calling
'wicked stable states.'

Now, this is not somewhere we want to go.

Wicked stable states are unpredictable,

they're contradictory.

When you try to fix one problem,
another problem shows up over here.

And the way things are going, right now,

with our forests
dying from climate change,

which feeds back to more climate change,

this is happening really fast.

But here's the beautiful thing:

It's precisely because
they're complex adaptive systems

poised for change,

that we can change this trajectory
from negative to positive.

Here's how we do this.

First, we've got to re-imagine ourselves
as part of this network.

Imagine yourself listening
to all the other creatures.

We can tap into that below-ground network
and become part of the conversation.

If we'd done this, we would never
have cut birch out of those forests,

the Douglas fir forests,

because we would have known it undermines
the resilience of the forest.

But we're still doing that.

But I'm still very hopeful,

because I know that once we tap into
this complex adaptive system,

into our role in it,

we can change our thinking,
we can change our behavior.

We can become part of this great system.

Remember when birch
was sending nutrients to fir,

and fir was sending them
back to birch, remember that?

Well, this just proves
that in ecosystems, there is no bigotry,

there's only reciprocity,

only mutual respect.

Just like in my cancer support network.

That's what we practice.

So finally, thirdly,

I know that once we understand

that we are deeply part of nature,

really part of nature,

not separate,

that we can become
part of the great strengthening,

that positive trajectory.

We have to stop treating nature
as our shopping mall,

and once we do that,
we can change the arc of the future.

Once, I thought that fairies
connected and protected the forest,

and now with my science,
I know I wasn't that far off.

(Laughter)

Using science, I've shown that precisely,
these unseen connections exist,

just like the Coast Salish
have been telling us all along.

They've shown, the science has shown,
that everything is connected

and communicating,

with respect and reciprocity.

And out of this comes balance
in our communities and our ecosystems.

And it's based on principles like kinship,

respect of elders,

and this gives rise
to complexity and adaptability.

And out of this, of course,
we have resilience.

Resilience to deal with things
like climate change.

So, I want to leave you
with one final, hopeful message.

I know, based on my experience,
and in my science,

that you, too, can own this,

that we are one.

Thank you very much.

(Applause)