All language subtitles for Our Planet - S01E08 - Forests-eng

[narrator] Just 50 years ago,

we finally ventured to the moon.

For the very first time,
we looked back at our own planet.

Since then, the human population
has more than doubled.

This series will celebrate
the natural wonders that remain

and reveal what we must preserve

to ensure people and nature thrive.

Forests.

Over half of all the world's trees,
evergreen and deciduous,

stand in these great assemblies.

[birds chirping]

[narrator] For many of us,
they are places of mystery and darkness.

They are key to our climate,
and home to countless unique species.

In the past, we have destroyed them
without hesitation.

Yet, forests do have
an astonishing ability to recover.

This is the southern edge
of the boreal forest,

the forest that dominates the far north.

It stretches eastwards across Russia
for thousands of kilometers,

and now, in the middle of winter,
it's largely silent,

seemingly empty of animals of any kind.

But this is the home
of an animal so rare it's almost mythical.

A Siberian tiger.

There are less than 600 of them.

[caws]

[tiger growls]

[narrator] These are the most intimate
pictures of them in the wild yet taken.

A male Siberian tiger patrols a territory
of almost 2,000 square kilometers,

and it has to do so
if it is to find enough prey

to keep itself alive
during the long winter.

This is an impoverished land
where food of any kind is scarce.

A pine cone.

Pine nuts provide vital energy
during the winter months.

Wild boar depend on these nuts.

For them, it has to be grab and go,

for they themselves are food for a tiger.

[squeals]

[narrator] This game of hide-and-seek
is played out over vast areas of forest,

as all the animals search
for the life-giving stands of pine.

Poaching has taken the Siberian tiger
to the brink of extinction,

but, since the 1980s,
their numbers have slowly increased.

These rare glimpses reveal

that their future still depends on having
vast areas of forest in which to hunt.

The boreal forest extends
from Russia in the east,

across Europe, to North America.

It contains 750 billion trees,

and it stores
over 40 percent of the world's carbon,

making it a vital element
in the fight against climate change.

During the winter, the days are so short
and the temperature so low,

that growth is at a standstill.

This far north,
the forest can support very few animals

compared to the rain forests
of the tropics.

Many are dependent on the supplement
to be found in its rivers.

[birds caw]

[narrator] In western Alaska,
both in spring and, as now, in autumn,

salmon, having left the ocean,

swim up rivers to reach
their ancestral spawning grounds.

Their journey from the sea into the forest
represents

the greatest transfer of nutrients
from one habitat to another

anywhere on Earth.

The fish are crucial seasonal food

for all the predators
that live in this forest.

Bald eagles live here the year round
and nest close to the river.

[piercing chirp]

[narrator] Young eagles,
still without white heads,

spend their first years
searching for food in the forest.

But, like this four-year-old female,

they're now big enough
to try and claim a place on the river.

At first, all she can get
are the scraps left by others.

And she can't get even these
without a fight.

[eagles chittering]

[narrator] She will have to
look elsewhere.

The boreal forest may be vast,

but the places where the salmon spawn
are known to all the predators.

As the rivers begin to freeze over,
competition becomes even more intense.

This youngster is lucky,
but her success is noticed immediately.

[chittering]

[narrator] She does have one advantage.

Females, even when young,
are larger than the males.

And here, size matters.

[cawing]

[narrator] As winter advances,

young and old have to meet
the challenge of the intense cold.

If she can survive,
she will have gained a place

in one of the greatest
and harshest forests on Earth.

A little further south

stand the last
of the great redwood forests.

Not so long ago, these great trees
grew throughout the Pacific Northwest.

Now, only five percent of them remain.

Here, conditions are less harsh.

Winds bring in warm, humid air
from the Pacific Ocean,

so the trees are able to grow
the year round.

Hidden in the vegetation
of the moist forest floor

is a richly populated underworld.

A male rough-skinned newt.

Every spring,
he is driven by a mysterious urge

to return to the pool
where he hatched as a tadpole.

And he needs to get there quickly.

Because there are
lots of others like him...

with exactly the same idea.

They're all searching for a female,

but trekking across hundreds of meters
of old-growth forest is not easy.

There is strong competition.

And the female is anxious to get going.

Once paired, he hangs on,

for she may take several hours
to discharge all her eggs.

Other males are only too eager
to displace him if they can.

Competition is so vigorous

that the females
in the center of these writhing balls

have been known to drown for lack of air.

But her first partner maintains his grip.

Within weeks, their tadpoles will hatch.

And none too soon, for the forest
is about to change dramatically.

By the end of the summer,
the sun has baked the forest so intensely

that they are as dry as tinder.

Strong winds drive the flames,

and temperatures rise
to 700 degrees Celsius.

Its aftermath is seemingly
total destruction.

The wind,
scouring the newly exposed forest floor,

kicks up dust devils of ash.

The ground appears to be devoid of life.

But the forest is far from dead.

Within only a few months,

flowers and tree seedlings
will rise from the soil.

Many, in fact, would not have germinated
had they not received a baptism of fire.

[birds chirping]

[narrator] Light streaming down
through the newly opened canopy

provides the energy
for a surge of new growth.

The older, well-established redwoods
have survived,

protected
by their thick, fire-resistant bark.

This natural resilience is essential
to the continued health of these forests.

Most forests, however,
cannot recover on their own.

Many are helped to recover by animals.

The trees and their inhabitants
are interdependent.

And nowhere
is this dependence more apparent

than in India's Western Ghats.

This globally important habitat

contains a third
of all animal species found in India.

[animals whoop and chirp]

[narrator] Lion-tailed macaques.

They feed on the fruits
of many kinds of tree,

and, in doing so,
they distribute the seeds,

which will emerge unscathed
with their droppings.

But few monkeys travel very far.

If plants are to distribute their seeds
across great distances,

they need another kind of transport.

Wings.

Great hornbills have wings
that are almost two meters across,

and they enable the birds to travel
long distances in search of food.

Hornbills feed on the fruit
of 40 or so different kinds of trees,

and transport
the indigestible seeds they contain

all over the Western Ghats.

So, it's to the trees' advantage
to attract the hornbill's attention.

The figs themselves,
although they taste nice,

are not, in fact, very nutritious,

so the hornbills have to eat
great quantities of them.

It can be tiring work.

But it's not a free-for-all.

A single fig tree in fruit
attracts great numbers of hornbills.

Competition between them is intense.

This aerial jousting between males
has never been filmed before

and its purpose is not really understood.

It may be that the birds
are simply squabbling over food,

but it seems rather more than that.

[squawking]

[narrator] The winner is able to
demonstrate his strength and skill

to visiting females.

The males certainly seem keen
to ingratiate themselves.

It's particularly important for hornbills
to get the best pairing

because, once established,
the bond between male and female

will last a lifetime.

The forest also benefits
from these squabbles,

because even a defeated hornbill

will spread seeds over wide areas
as he searches for his next meal.

The relationship
between trees and animals in a forest

is not always so harmonious.

This is Africa's largest forest,
the Miombo,

named after one of its common trees.

It stretches for over a thousand miles,

from Angola in the west
to Mozambique in the east.

At the height of the dry season,

the Miombo attracts animals
from all across southern Africa.

[trumpeting]

[narrator] Elephants prefer grass
if they can get it. It's very nutritious.

In its absence,

they browse on the abundant leaves
and branches of the Miombo.

[elephants huffing]

[narrator] But they're not the only
hungry ones here.

These mopane worms

are not worms, of course,
but caterpillars.

They hatch simultaneously in huge numbers.

And just as the forest
is putting out new leaves,

they begin their attack.

They feed so voraciously

that in just six weeks
they increase their size 40 times.

By the time they're fully developed,
this million-strong army

will have stripped the entire forest
of its foliage.

But the Miombo bounces back.

With the caterpillars gone,

the trees produce
a second growth of leaves.

This fresh feast then attracts elephants.

They are less fussy than the caterpillars.

They will eat every part of the tree.

And a hungry elephant can munch through
200 kilos of vegetation in a day.

Yet, even this destruction
has its benefits.

It shapes the forest in a way that helps
one of Africa's most endangered animals.

Hunting dogs.

They're seen most frequently,
and most easily, on grasslands.

But, in fact, these open forests
are their preferred habitat.

[grunts]

[narrator] Browsing elephants
open up a forest,

and that attracts the animals
on which the dogs prey.

[barks]

[dogs yipping]

[narrator] For the dogs, the Miombo forest
is perfect hunting country.

And it's also an excellent place
in which to bring up pups.

The pups greet the adults
returning from a hunt

with great excitement.

[squealing]

[narrator] Food.

The first three months of the pups' lives
are spent sheltering underground.

[soft growling]

[narrator] Now, they are confident enough

to stay out in the open
for much of the time.

And then, like all puppies, they have fun.

Playing is important for the youngsters,

for as they do so,
they establish the social bonds

that they will need when they start
to hunt together as a team.

- [bird squawks]
- [squealing]

[narrator] The Miombo has always been
important for hunting dogs,

both as a place to find prey
and as a refuge.

Never has it been more crucial

for the survival
of this endangered species than now.

But they will only survive
if other creatures are here

to create the kind of habitat they need.

[elephant lows]

[narrator] Madagascar has a forest

dominated uniquely
by one of the oddest of trees.

Baobabs.

The island has been isolated
for over 80 million years.

During that immensity of time,
its animals and plants

have evolved into forms
quite different from any elsewhere.

This makes them one of
the most precious forests on our planet.

This is not a monkey,
but a distant relative, a lemur,

and there are
at least 40 different kinds of lemurs,

all unique to Madagascar
and all endangered.

[lemur hoots]

[narrator] Lemurs are crucial
to the forest.

Without them,
some species of tree cannot survive.

The forest even has
its own specialized lemur hunter.

It's Madagascar's top predator,

and its presence is cause for alarm.

It can grow
to a length of one and a half meters,

and it's very seldom seen in the wild.

It's a fossa.

For most of the year, fossas are solitary,

but in the breeding season, they assemble
in a way that is all their own.

Each mature female takes up residence
in a special mating tree.

Half a dozen or so male fossas
have gathered in the forest below it,

but she is clearly occupied.

So, one of the males leaves his scent.

A visiting card,
just to show that he called.

He will just have to wait around
and see whether she takes any notice.

Her present engagement can last all night.

With its top predators distracted,
the rest of the forest animals

can go about their normal nightly business
undisturbed.

These are immature leaf bugs,
a species found only here in Madagascar.

Why they have this extraordinary shape,
no one knows.

They feed on tree sap,

absorbing the part they need
and excreting the rest as a sweet liquid

sometimes known, perhaps flatteringly,
as honeydew.

And honeydew, in turn, provides food
for a particular species of small lemur.

The gray mouse lemur
is only 15 centimeters long,

one of the smallest primates in the world.

It's very active
and needs an energy-packed food.

And while the sugar drops
are clearly delicious,

they're not very sustaining.

So, she's not going to let
a single drop go to waste.

The male fossas below
are still awaiting their turn.

[animal screeches]

[narrator] So, having eaten
as much as she can,

she retreats
to the safety of her nest hole

to sleep during the daylight hours.

Things are not looking so satisfactory
on the ground

around the fossas' mating tree.

[sniffs]

[narrator] The pair above
are clearly still engaged.

He will either have to find
another mating tree or be very patient.

But he may well fail altogether.

A third of Madagascar's fossas
have disappeared in the last 20 years,

a result of the continued destruction
of their forests by people.

Since these pictures were recorded,

this forest,
and the unique life it once contained,

have disappeared altogether.

Only three percent
of Madagascar's dry forest remains.

Worldwide, we have now destroyed

over half of the forests
that once flourished on our planet.

Not only are we losing the animals
that once lived in them,

we are also changing the climate
of the entire globe.

But our planet's forests,
if given the chance,

are almost unbelievably resilient.

Perhaps the best proof we have
of their ability to recover

can be seen on the site
of one of our greatest disasters.

Chernobyl.

In 1986, one of the four reactors
at the Chernobyl nuclear plant exploded.

It turned this utopian vision
of the future into a ghost town.

Over 100,000 people
were immediately evacuated,

never to return.

The fallout zone was declared
uninhabitable for the next 20,000 years.

Yet despite the radiation,
there has been a remarkable recovery.

Within only a decade,

vegetation began to germinate
in the ruined city.

And as the forest reestablished itself,
animals began to appear.

At first it was thought
that these were rare visitors,

but it soon became clear
that the former city

was occupied by an established
and thriving wild community.

[chirping]

[narrator] Within only 20 years,

science has recorded
populations of animals

similar to that
in the wilder parts of Europe.

Roe deer are now a common sight,
wandering through the suburbs.

Herds of the endangered Przewalski's horse

now roam freely
through the once busy city.

Most surprising of all perhaps,

the top predator of these forests
has reappeared.

Wolves.

Hunters like these would only return

if their prey and the surrounding forest
is also thriving.

Now, studies have shown

that there are seven times more wolves
inside the exclusion zone than outside it.

No unprotected human being

can stay here for long
without lethal risk.

But in driving us out,

the radiation has created space
for wildlife to return.

The dramatic recolonization of Chernobyl
in the space of only 30 years

is proof
of forests' extraordinary resilience.

If we choose to give forests
time and space,

they could reclothe the earth

with much of the rich and varied
communities of animals and plants

of which we have, so recently, robbed it.

A future with more forests
is key to the resilience of our planet.

Please visit ourplanet.com

to discover what we need to do now
to restore our forests.

♪ I can hear the whole world
Singing together ♪

♪ I can hear the whole world
Say it's now or never ♪

♪ 'Cause it's not too late
If we change our ways ♪

♪ And connect the dots to our problems ♪

♪ I can hear the whole world
Say we're in this together ♪

♪ We're in this together ♪