All language subtitles for BBC.Secrets.of.our.Living.Planet.3of4.The.Magical.Forest.XviD.AC3.MVGroup.org.eng

Ten million species live on planet Earth-

Each one is remarkable-

But none can survive on its own-

All life depends upon connections.

Unexpected, invariably complex,

beautiful relationships between
millions of plants and animals.

This time, in our seasonal forests,

why does this lynx need a caterpillar?

Why does the tree need the fish?

And why does this truffle fungus
need one of these?

Flying squirrel!

Connections like these
form the planet's great ecosystems-

They're vital for all life-

I want to show you our world
as you've never seen it before.

New England in autumn.

There really can't be a more magical place
anywhere on Earth

to appreciate that dramatic transition
between summer and winter.

But we mustn't get blinded
by this natural fiesta,

because such an extreme transformation
is a huge challenge for life,

and autumn is just one of many
transformations the forest must face-

From summer to winter, this land of plenty
will appear to collapse,

before attempting to rebuild itself
all over again in the spring-

To see how, 1'm going to what is, for me,

the greatest seasonal forest
on the planet-

The wooded wilderness that stretches
right across North America-

From the land of the Canadian lynx

to the land of the grizzly bear-

Our story begins in autumn-

As the days are drawing shorter,
less light is feeding the forests-

Deciduous trees are shedding their leaves-

Many creatures are burrowing away
to escape the cold-

And others are simply leaving-

But there's one animal
with a crucial job to do,

now, before the winter sets in-

1t's a job the entire forest depends upon-

The best time to see them is in
the first couple of hours after dark.

And what I'm hoping is
that if I stand here

and stay really quiet,
I'll be in for a real treat.

1t's a creature 1've waited all my life
to see, but they move so fast!

0h! Did you see that?!

That was amazing,
it went right past my face!

Flying squirrel!

They really are expert gliders-
They can glide for up to 2OO metres!

When I was a kid, I was obsessed
with things that were, you know,

not meant to fly.

Flying fish, flying frogs,
flying lizards, flying squirrels.

And this is the first time
I've ever seen them.

It was worth a 45-year wait - honestly!

Did you...? 0h! Did you see that?!

I felt it, it went right through my hair!
Seriously! Centre parting!

It was like having a sheet of A4
coming right over my face,

and as soon as they hit the tree,
they're running and up they go.

They're just crisscrossing
all of the trees.

And they immediately scamper up to the
top and then take off and glide again,

and sometimes, I've noticed, they can
even change direction during flight.

Urgh! 0ne hit me in the chest!

It doesn't come better than that, does it?

It doesn't get more exciting.

But what on Earth
have they got to do with our story?

Well, at the moment,
these flying squirrels are out and about

in the woods trying to find
as much food as possible

before the weather turns nasty
and the winter kicks in.

But what are they after?
Well, they're after these - truffles.

They're the fruiting bodies of fungi

and they appear in the damp cool
of autumn-

1n preparation for winter,

the hungry squirrel needs to hoard food
such as truffles-

But the truffles also need
the squirrel to eat them-

As the squirrel moves through the forest,
the spores are dispersed-

And that's crucial-

Not just for the truffle,
but for the trees-

What's so special about these truffles?

They certainly don't look much,

and the smell can be said to be
an acquired taste.

And they're not just here
as another organism to be eaten

by hordes of hungry squirrels either.

Because without these truffles

and all of the other fungi
here in the wood,

this woodland simply couldn't function.
It couldn't exist.

Why?

Well, take a look beneath the soil
down here.

Each truffle has thread-like roots
extending from it-

The threads extract nutrients in the soil
from rotting material, like the leaves-

And, cunningly,

they also tap into the roots of the trees
to siphon off sugars-

But this is not a one-way relationship,
because the tree

can now tap into the nutrients
extracted by the fungal threads-

This symbiotic relationship
between the trees and the fungus,

where each is dependent on the other,
clearly helps the tree grow,

but it's not only that.
It greatly extends the reach of its roots.

Because in effect, they become
as extensive as the fungal network

that they're connected to.

1n autumn, throughout the northern
hemisphere, trees use fungi

to extend their roots
and absorb sufficient nutrients

for the big freeze ahead-

1 love this little web of relationships-

The squirrels, the fungi, the trees-

1t ensures that they're all ready
to face the winter-

But for me, one of the most
magical relationships of all

is seen on the far west coast of Canada,

as one of the world's most ancient forests
prepares for the oncoming challenge-

Here, 1 can stand at the foot
of thousand-year-old cedars

and 9O-metre tall sitka spruce trees-

The combination of large mountains
and ocean winds

generates unusually heavy rainfall,

earning this place the title
the Raincoast-

There's so much rain in autumn
that the rivers are swollen-

And that is vital
to the forest's survival-

There's a significant event happening here

which allows the whole forest
not only to survive the winter,

but also to flourish throughout
the course of the year.

But, you know,
the really incredible thing is

that this key to life is not here
in the forest at all at the moment,

but it will be soon.

After years at sea,
salmon are returning to spawn

in the same forest streams
in which they were hatched-

And the swollen rivers
make it easy for them

to swim deep into the forest-

But the scent of home also draws them
irresistibly towards danger-

Predators make the most
of this banquet of seafood-

But none of them compare
to the most formidable fish-eater of all-

Grizzly bears!

Just look at this.

There's a female here,
about 40 metres in front of me,

in the shallows fishing for salmon.

Behind her, on the bar over there,
she's got three cubs.

They're not struggling
to catch the fish here,

there's such a tremendous surfeit
of tired salmon out there.

All she really has to do
is wander into those shallows

until one comes close.

And then she can grab it,
much to the delight of her cubs.

For these cubs, it's the first salmon run-

They've got to learn how to catch fish
by watching their mother-

Look at this, look!

This is the adult grizzly
that's just leapt off of the island there,

and caught a salmon, look at that,
right in its mouth.

Overjust six weeks in autumn,

tens of millions of salmon
are going to return to these rivers-

And during the course of a day,
one adult bear like this can eat

40kg of salmon, and during the course
of the salmon run, 1,400kg.

That's just one bear's intake.

But every salmon caught by these bears
increases their chances of survival-

And they are incredibly important
to these bears,

particularly at this time of year

when it's essential they bulk up
as quickly as possible

before they slip into hibernation
with the winter coming.

This cub hasn't quite
got the hang of it yet-

But he hasn't got long- The salmon run
has only got a couple of weeks to go-

Until they learn,
Mum has to work even harder-

Every salmon caught
makes a real difference-

These bears, those that are close
to a huge amount of salmon,

grow 80%/ larger than those in other areas.

They have 25%/ more cubs

and occur at densities 50 times greater.

So salmon, frankly,
are great news for bears.

Exciting as it is to watch,

there's a lot more going on here
than simply bears catching fish-

And the reason
is thanks to what happens next-

And the only way to see it
is with remote cameras

positioned deep in the forest-

These younger bears have carried fish
3O metres from the river-

Because here they're less likely
to be challenged by hungry adults-

So they can eat in peace-

There's so much fish available,
they just eat the richest bits

to lay down enough fat for hibernation-

The rest appears to be wasted,
abandoned on the forest floor-

Along with our camera-

The aftermath of this feast
is unbelievable-

Up to four tonnes of carcasses are left
in an area the size of a football pitch-

But what have dead fish got to do
with the forest preparing for winter?

Well, this is where it starts
to get really intriguing,

because the catching of the salmon
is just the start of it.

Bears aren't the only creatures
attracted by such a feast-

A banana slug- At 25cm long, it's one
of the largest slugs in the world-

And masses of insects-

These flies won't survive the winter,

but if they plant their eggs
in the salmon's flesh,

their offspring might-

This flurry of activity eventually breaks
the flesh down into simple nutrients

that are absorbed into the soil-

The significance
of all of this decaying fish

goes far beyond it being
just a feast for scavengers.

Without all of these rotting salmon
accumulating here every autumn,

this forest would be
a very different place.

The salmon nutrients in the soil
are taken up by the fungi-

So this ancient forest is better equipped
to face the almighty change

that's fast approaching-

For forests in the northern hemisphere,
time has run out-

Every day, the sun sinks lower in the sky-

Winter.

And on the face of it,
all of the life here

seems to have just gone away.

Those truffles and the seeds,

they're locked away
underneath all of this snow.

The salmon run is over.

The vegetation - look at it -
it appears just to have shut down.

Even the water is in short supply.
It's all frozen.

All of those connections
appear to be broken.

The fungi have reduced their recycling
to a bare minimum-

And the trees they're connected to
are producing little in return-

The deciduous trees pre-empted
the winter by shedding their leaves-

The conifers are slowing down too-

The waxy coating on the needles
protects their leaves from the cold-

But not everything here can exist
in a state of suspended animation.

Some of the animals
have to remain active,

and surviving in conditions like this
isn't easy.

The icy cold is the cue for the bears
to leave the forest altogether-

With the salmon run over,

they are retreating to their winter dens
up in the mountains-

They must spend the entire winter
living off their fat reserves

gained by feeding on all of those salmon-

The squirrels and other small mammals
must keep their activity to a minimum---

---only occasionally venturing out
to retrieve their autumn caches-

The lower the temperature falls,
the more vulnerable creatures become-

Winter has been too brutal
for this young white-tailed deer,

but at least it's an opportunity
for some nocturnal scavengers-

A racoon-

Out of the forest, a fisher,
a relative of martens and weasels-

And it's smart enough
to keep this meal to itself!

But there is more to this lifeless-looking
forest than just the scavengers-

For most creatures,
winter is a brutal and unforgiving time.

But others actually thrive
in these conditions.

You see, for animals
that have adapted to live in winter,

this stripped-down forest ecosystem -
well, it's a wonderland.

1n winter here,
there are beautiful connections

between some of the forest's
most enchanting characters-

There is one predator here,
an incredibly important animal

that has no intention
of avoiding the snow,

because, unlike me,
it's perfectly adapted to it.

But it's an enigma,
a really, really shy animal,

one that's difficult to study.

Having said that,
scientists have been tracking them

through the forest here
for more than a decade.

Researchers from the Maine Department
of Fisheries and Wildlife

have set a trap to catch one alive-

With those distinctly pointed ears,
it can only be a Canadian lynx-

Lynx are the world's
most northerly dwelling cats-

And this particular lynx is well known
to chief scientist Jen Vashon-

The ear tags are blue with white.

- That indicates it's L1 -1 1 .
- (LYNX BARKS)

He's called L 1-1 1
and was born in May 2OO4-

They've discovered that he is just one
of hundreds of lynx living here-

JEN: It's too intimidated
with everybody right there.

1n fact, there are more lynx
living in these eastern forests

than anywhere else in North America-

Now, the fact that L1 -1 1 has lived
all of his life in this frozen forest

has to mean that this is
a perfect place for a lynx to live.

But how can a top predator
like this survive

in such a stripped-down environment

when there appears to be
so little else here?

The tracks of their prey are everywhere,

but actually finding one
is a real challenge,

because its winter camouflage is perfect-

It's taken some finding,
but it's there - the snowshoe hare.

You can just make out
its beady little black eye

and the black tips to its ears.

And these things form 80%/
of the lynx's diet,

but as you can see,
they don't make it easy for that lynx.

Their camouflage is astonishing.

In the summertime, they're brown,

but in the winter,
they moult through to a white coat.

But they also use this thick brush.

It provides them with excellent cover
to hide from the lynx,

also hide from the elements,

but it's also crucial
in keeping them alive,

because they climb on top of the snow and
nibble at all of the shoots and the bark

growing from all of this brush.

Look at that - beautiful!

And with those big snowshoe feet,

it just sort of floats across
the surface of the snow.

What the snowshoe hare needs most
to survive the winter

is a specific type of vegetation-

1t must be the right height to eat

and provide enough cover
to hide from all of those lynx-

So the vegetation here must be perfect-

And the reason that it does grow into
this perfect environment -

well, you could never guess-

The most beautiful thing about this story
is that the lynx, the hare,

patches of cover like this
amongst the forest

didn't happen by chance.

They're all controlled
by the most unlikely of creatures,

a tiny thing, less than the size
of one of my fingernails.

And at the moment, it's hiding,

having burrowed into the bark
of one of these trees,

or perhaps in a crack in a log
lying on the forest floor,

covered with frozen snow.

But it's there and it's waiting.

It's waiting for springtime.

As the hours of daylight increase
and the ground thaws,

as if by magic,
the northern forests change again-

As new leaves appear,
trees start producing sugars,

and that's good for fungus in the soil-

Entwined with the trees'roots,
they can siphon off some of these sugars-

But not everything appears
so harmonious-

1n the land of the lynx, something
extraordinary is happening to the forest-

These trees may have endured the winter,

but now it's spring, they're under attack-

Some are even dying-

But what's happening here now is vital

for how this ecosystem functions
over the year-

This defoliation is entirely natural.

And I might be able to find
one of the culprits down here,

although they're quite tricky to spot.

They live in these fresh, green shoots.

Yes, here we are.

Now, wrapped delicately in these leaves

is a species that is single-handedly

influencing the ecology
of this entire forest.

Inside this nest is the caterpillar
of the spruce moth - the budworm.

And it hasn't only wrapped itself up
in those leaves

to hide from predators,
because it's eating them as well.

And it doesn't just eat the leaves.

It also eats the buds, the flowers
and the cones on the tree here.

Up in the canopy,
a tiny budworm caterpillar

has just emerged from hibernation

and it's racing to fatten itself up-

When it's finished on one branch,
it releases a strand of silk

and abseils down to the next-

1t's a risky business
being a juicy, fat caterpillar-

You're in danger of being spied by all
of those birds just back from migration-

But the caterpillar has a plan-

1t uses its silk to weave the needles
together and hide in a dense web-

Now, the springtime assault
by these caterpillars

is bad news for the trees-

But for other inhabitants
of these forests,

these caterpillars are heroes-

It's thanks to the behaviour
of this species

that one of North America's most elusive
and charismatic predators -

the Canadian lynx -

is enjoying a bit of a renaissance
in forests like this one.

But the caterpillar lives all the way
up there, in the canopy.

Whilst the cat with the pointed ears
is prowling around down here.

So how can a humble insect like this

have any impact
on a formidable thing like that?

I bet the lynx never even sees
the caterpillar

throughout the course of its life.

Why does the lynx need the caterpillar?

The clue is how they affect
the lynx's prey on the forest floor-

For decades, scientists have studied
budworm caterpillars,

and a remarkable pattern has emerged-

They've discovered that the population
of caterpillars fluctuates dramatically-

And at the peak of the cycle,

there can be tens of thousands
of budworms in a single tree-

And this has devastating consequences-

Whilst these dramatic natural events

might be a catastrophe
for the established trees,

for anything trying to grow on the
forest floor, they are an absolute bonus.

In here, where it's dark,
there's very little,

very poor diversity -
just some mosses and a few ferns.

But as soon as
there's a break in the canopy

and the sunlight can flood in -
well, look at the difference.

Lots of wild flowers, there's young maple
coming through here,

mountain ash and, most importantly of all,
regenerating spruce and fir.

Now, the hares essentially need
these regenerating conifers as shelter.

And, of course, what's good for the hares
is also good for the lynx.

1t's such an elegant connection-

Without the spring emergence
of the hungry caterpillars

to chew holes in the dense canopy,

there wouldn't be enough light
flooding the forest floor-

And with less light down here,

there would be less growing for
our snowshoe hare to forage and hide in,

and then there would be nothing

for L 1-1 1 and all of those
hundreds of other lynx to eat-

And that's why the lynx
needs the caterpillar.

And now it's spring,
there's no better time

to see what the future holds
for the lynx population-

Wildlife biologist Jen is doing a count-

She's detected a signal
from a radio-collared female-

There she is-

But there might be something else here-

Safe inside a den, a lynx cub-

He's just a few weeks old-

(CUB SQUEAKS)

His eyes aren't even open.

Jen must work fast before Mum returns-

Thanks to the timing of the budworm
opening the canopy this spring,

there's going to be enough prey
for these lynx to hunt next winter-

(CUB SQUEAKS)

Far away to the west, the Raincoast forest
is coming back to life-

Thanks to the richness
of the autumn salmon run,

the bears have survived the winter-

They've now returned to the forest,
looking for something to eat-

They'll survive on vegetation
until the next salmon run-

The emergence of the bears

is a cue for scientists to conduct
a rather risky experiment-

They need a large, hungry bear-

1t's the only way to measure

the impact of
all of those salmon on this ecosystem

and to understand why this vast,
ancient forest has thrived for so long-

For such a big question,

the methods employed by senior researcher
Chris Darimont seem a bit curious-

He's equipped
with a can full of old salmon guts,

effusing probably
the most disgusting smell known to man-

CHRIS: This is wonderful stuff.

But he hopes
the bears are going to love it-

He's made an aerial lure,

so the wind will carry this distinctive
perfume deep into the forest-

The wind - extra boost.

Now they surround the area
with barbed wire-

And it's this that they hope will collect
what they're so interested in -

- a single hair from a visiting bear-
- (CAMERA BEEPS)

Now the site is prepared,
it's time to set some remote cameras---

---and beat a hasty retreat-

Personally, 1'm very happy to watch
from a safe distance-

1t's not the smell -
some of those bears are huge-

Look at the size of this bear!

As a trap, this is the perfect bait,
it's working brilliantly.

The bears have come in

and they're snagging themselves
on the wire there.

You can see it vibrating about.
And that's justwhat we want.

Fresh out of hibernation,

it seems they can't resist
this pile of stinking salmon.

This one's even rolling around
in the stuff now.

No doubt it values the scent -
I'm not sure we would.

The bear's coat has been growing
for nearly a year,

but soon it will be moulted and lost-

The more bears we can attract, the better-

Now the coast is clear,

and it's time to retrieve any fur
from the barbed wire-

So what on Earth can hair tell us
about this forest ecosystem?

Well, hair is made of protein

sourced from whatever the bear
has been eating over the last year-

And by analysing this hair,

science can reveal an astonishing level
of detail about a bear's life-

We can learn so much
from a single bear's hair.

So I know, for instance, that this one
has come from a female grizzly.

I know exactly what it's been eating
even on a week-by-week basis,

where that food has come from and even
the impact on the quality of its life.

So this bear has been getting
most of its protein,

not from the forest around here

but actually from the deep ocean,
via the salmon.

And we know that,
throughout the course of the year,

80%/ of that bear's protein
has come from these salmon.

And that's surprising, because, remember,

they're only available to the bear
for a few weeks during the autumn.

And yet the impact
is clearly lasting all year.

So how come the bears appear to be
so full of salmon?

Well, back in autumn,

we saw the bears scattering fish carcasses
all around the forest floor-

As the protein
in those rotting salmon broke down,

nitrogen from it accumulated in the soil-

And this salmon nitrogen
is like fertilizer-

So in spring,
nutrients all the way from the ocean

gradually appear
in all the vegetation growing here-

Just in time for the hungry bears to eat
as they emerge from hibernation-

And hungry bears have huge appetites -

they'll eat a third of their body weight
every day-

That's why their bodies
appear to contain so much salmon-

But the impact
of this ocean-borne nitrogen

extends far beyond bears and their food-

This particular form of nitrogen
can be found in almost all of the animals

and plants that appear here in the spring-

These rufous hummingbirds
have migrated to the forest to breed-

They're drinking nectar from plants
that have been fertilized by rotted fish-

So they'll carry the same salmon nutrients
with them

as they fly through the forest-

And many of the insects
pollinating the plants now

were incubated in that decaying flesh
back in the autumn-

As they themselves are eaten,

the salmon nutrients
are spread even further-

Thanks to the bears, the insects
and the birds,

this salmon fertilizer is spread
deeper and deeper into the forest,

sometimes as much as 800 metres
from the river.

And this pulse of nutrients

then allows the organisms which define
the forest itself to prosper...

...its trees.

Dr Tom Reimchen
can measure exactly how much

these vast old trees need the fish-

The secret is to look inside the tree
by taking a core sample-

Written on it is the entire story
of this 3OO-year-old tree-

T0M: The rings I see are two, three,
even four millimetres,

which continues back to even the early
parts of the 1 800s, late 1 700s.

Tom has taken similar samples
from thousands of trees-

An entire forest is lined up in his lab,

each tree waiting to tell its own story-

1n this seasonal climate, annual rings
are created as the tree grows-

From these rings, he can determine
not just the age of the tree

but also the amount of growth
in each year-

Some of the rings are thicker than others,

showing that the tree has grown more-

Like the bear fur,
each annual ring can be analysed-

Tom can search
for the same type of nitrogen

that's found in the bears'hairs -

it comes from the ocean
and it's called nitrogen-1 5-

And the data will tell us

just how much nitrogen in those trees
comes from all those salmon-

I think this is really exciting.

You see, the annual growth rings here

show the presence
of the stable isotope nitrogen-1 5,

which significantly comes from the oceans.

It could only have been carried here
by the salmon.

Now, look. Here is the present,

the bark on the outside of a tree.
So these rings here represent perhaps

about the last 1 5 years
and they're very closely packed together.

But here, back in the 1 980s,
the rings are twice as thick.

The trees have been growing twice
as much during the course of a year.

So perhaps the salmon runs then
were even more productive

than they have been recently.

But that's not the best thing.

Come and have a look at this.

By measuring the abundance of that
nitrogen isotope in this material,

I can tell you that majestic old giants
like this beauty here

are actually composed of up to
85%/ material that's derived from salmon.

Now, when I was a teenager, I remember
learning that I was made of carbon,

and carbon could only be formed
when stars died.

Effectively, I was made of dead stars,
and that struck me as terribly romantic.

But look at this.
This is a forest made of the ocean!

That's why the tree needs the fish.

Without this
unlikely sounding relationship,

this magnificent ancient forest
just wouldn't be the place it is today-

But there is one more relationship

crucial to seasonal forest
all around the world

when it comes to surviving
constant change-

And it's one that reaches
its greatest intensity now,

at the height of summer-

1t's the driest time of year,
and the trees need water-

Fortunately,
united with their fungal partners,

the trees
have massively extended their roots-

Fungal threads in the soil
are absorbing water

and passing it to the tree-

But what has only recently
been discovered

is the sheer scale
of these fungal root networks-

A single cubic centimetre of the soil here

can have a mile of these
white fungal threads running through it -

they're called mycorrhizae.

And for me,

it's these organisms that are
the real secret of the forest here.

1n the lab,

the genetic fingerprints of individual
mycorrhizae have been identified-

By mapping an area 3O metres across,
it's been discovered

that individual fungi
connect to more than a single tree-

Just one fungus

can be joined to 8O%
of all of the plants growing here-

And, amazingly, these physical links

enable different species of plants
to exchange nutrients-

Older established plants
are even nurturing younger weaker ones-

1t acts like
an underground welfare system-

These giant webs connect all of the trees
in this forest,

and keep them, and all of the things
that are dependent upon them, alive.

That's why scientists
are calling this the wood-wide web.

1t's thanks to this natural phenomenon,
the wood-wide web,

that together the trees
in the forest ecosystems are resilient-

Resilient enough to cope
with the dramatic changes

they encounter every year-

And what's really amazing
is how the web is built-

It's thanks to hungry mammals
like our flying squirrels

that this essential life-support system
is effectively maintained.

It's actually fair to say that these trees
wouldn't be standing here,

wouldn't be thriving,
unless a squirrel had eaten a truffle.

And thatis fantastic!

1t is fantastic-

1t's fantastic to think
that what animals do in one season

influences the forest ecosystem
throughout the year-

1t's almost as if all of these stories
are choreographed-

The arrival of the salmon
at exactly the right time

to fatten the bears for winter.

Then the emergence
of the lush green vegetation

fertilized by those salmon to sustain the
bears when they emerge from hibernation.

The squirrels foraging for truffles
in the autumn time,

and sowing their spores
throughout the forest

to grow a fungal network that joins
all of the trees and all of the plants,

and provides them with nutrients.

The budworm chewing a hole
in springtime in the canopy,

so that in summer, sunlight floods down
to the forest's floor

and produces the perfect hunting habitat
for lynx.

It's all in the timings.

And it's this that makes
these temperate forests

such magical places.

If you'd like to know more about the
fascinating web of links between species,

the 0pen University has produced some
material both to inform and inspire you.

For your free copy, or to find out more
about 0pen University programmes, ring...

0r go to the website...

And then follow the links
to 0pen University.

And join me next time
when 1'll be travelling

to some of the world's
greatest water habitats-