All language subtitles for 00018.track_4768

The biggest living thing

that exists on this planet
is a plant.

The giant sequoia tree
of California.

Plants, whether they are
enormous, or microscopic,

are the basis of all life,

including ourselves.

We depend upon them for every
mouthful of food that we eat

and every lung full of air
that we breathe.

The plants of our planet
flourish live remarkable lives

yet, for the most part,

the secrets of their world
have been hidden from us...

...until now.

Now we have new ground-breaking
technology that enables us

to enter
their extraordinary world

and see their lives
from their perspective.

In this series, we will uncover

the dramatic and unexpected
behaviour of plants...

...and explore the beautiful...

(THUNDER CRACKS)

...but challenging landscapes
in which they live.

The tropics - the richest
and most competitive place

in which to survive.

The bizarre water world...

...where giants
fight ferocious battles,

and plants eat animals alive.

Deserts...

...a world of extremes.

Seasonal lands...

...where survival depends
on precision timing.

And everywhere,

there are intimate and critical
relationships

between plants and animals.

This is a world
that takes you...by surprise.

See our planet as
never before -

from the plants' perspective.

This is The Green Planet.

(BIRDS AND ANIMALS CALL)

Rainforests,
like here in Costa Rica,

are the richest and most
dynamic environments on Earth.

They cover only
a very proportion

of the Earth's surface...

...and yet they contain
over half of all the world's

animal and plant species.

Up here, the forest's canopy is
bathed by life-giving sunlight.

The branches of the great trees

carry rich, flourishing
sky gardens...

...home to countless different
kinds of beautiful plants.

Each species has evolved
its own exquisite solution

to the challenges of survival.

This forest world
may look peaceful,

timeless and unchanging,

but that is far from the truth.

The battle is at its fiercest
on the forest floor...

...where only 2% of
the sunlight filters through.

Plants here have to
bide their time.

Their opportunity comes
when an old tree dies.

When that happens, sunlight
floods the forest floor

for the first time
in perhaps 100 years.

The seedling's wait is over.

It must now race skywards

and claim a place
in the canopy.

But it's not alone.

(LEAVES RUSTLE)

Rivals are everywhere,

each with its own
survival strategy.

Some plants,
like this monstera,

stretch out divided leaves
to collect what light they can.

This vine is groping blindly
around with its tendrils.

It attempts to reach the light
by hitching a ride.

Its tendrils are highly
sensitive to touch.

And a suitable target
is in range.

Got it!

The vine tightens its grip

and begins to haul itself
upwards.

But it's now overtaken

by the forest's
fastest-growing tree.

A young balsa.

Its giant leaves are already
40cm across

and are stealing the light
from its rivals below.

But the balsa's battle
is not yet won.

Other, different vines
are lying in wait.

Each is armed with dozens
of claw-like hooks.

If just one hook gets a grip,

the vine will be able to
smother its victim.

But the balsa is defended by
a shield of slippery hairs.

The vine's hooks
just can't get a hold.

The balsa brushes them aside...

...and continues to rush
skywards...

...leaving the losers
in its shadow

to fight among themselves.

This balsa has won its battle
for the light.

And it's done so
in a little over a year.

Balsa beat its competition

because of its extraordinary
adaptations for swift growth.

Under the microscope, balsawood
looks like a honeycomb.

It contains more air than wood,

so not only
can it grow very fast,

but it gets the maximum height
for minimum weight.

But fast growth needs
something else.

Fuel...

...and lots of it.

That fuel is created in
a plant's leaves,

as they soak up the sun.

It's a process called
photosynthesis...

...a chemical reaction that is
the basis of all life on Earth.

Leaves are covered by thousands
of microscopic pores

called stomata.

When open, they extract
carbon dioxide from the air,

and using energy from the sun,

combine it with nutrients
to build the plant's tissues.

And critically for us,
the process releases the oxygen

that we and all animals need
in order to breathe.

(BIRD CALLS)

But for plants,
there is a downside.

These precious, energy-packed
leaves attract predators...

...in every shape...

...size...

...and agility.

A sloth can only move slowly,

but you don't need speed
to gather leaves,

and it eats nothing else.

Plants are under attack
from all kinds of leaf-eaters,

but the most voracious by far
is hardly ever seen.

It consumes 50,000 leaves
every day.

It's called leucoagaricus.

It's neither animal nor plant.

It's a fungus.

It lives five metres
underground,

far from the leaves
that it devours.

To get them,

it employs the best
leaf-gatherers in the tropics.

Leafcutter ants.

Millions of them provide
the fungus with its food,

and in return, the fungus
cultivates tiny mushrooms

as food for the ants.

The fungus releases
chemical signals

that tell the worker ants what
type of leaf it wants to eat.

Scouts are sent out
with the latest orders.

Worker ants will travel
hundreds of metres

to find the right kind.

Today's crop is being taken
from a young bixa tree.

Just a few years old and still
battling to reach the canopy,

it can ill afford to lose
any of its leaves.

(CRUNCHING AND SLICING)

Between them, the ants can
demolish a large leaf

in a matter of minutes.

The sound of cutting attracts
more ants.

Now the pieces are carried back
to the underground fungus.

The ants can run at speeds
of two metres a minute.

And each can carry a load
ten times its own weight.

It's a river of leaves across
the jungle floor...

...part of a vast network
that extends for miles

through the forest.

To avoid congestion,

worker ants dig trenches
around obstacles.

Thousands of pieces
are delivered every hour

to the waiting fungus.

Fed by
such a continuous supply,

the fungus grows rapidly,

filling the chambers
in which it lives...

...so the ants excavate
more space.

It seems that the fungus has
the upper hand...

...and the bixa tree
will not survive.

But it fights back...

...using chemical warfare.

The bixa tree floods its leaves
with toxins

that could kill
the distant fungus.

As the ants carry the fragments
back, they are themselves

poisoning the fungus
on the tree's behalf.

It's a long-distance attack.

As the poison takes effect,
the ants sense

that their fungus
is weakening...

...and they respond to
its signals

by changing to another
source of leaves.

So the plant's
chemical response

forces the ants to constantly
switch from tree to tree.

Strike and counterstrike.

And that ensures that enough
leaves remain uneaten

for each tree to recover.

(BIRDS AND ANIMALS CALL)

Once a plant becomes adult,

it can switch its energies

from growth to reproduction.

The tropical forests of the
Americas stretch from Mexico

to the southern reaches
of the Amazon.

They contain more than 100,000
different species of plant,

each with its own particular
survival strategy.

One species that has adopted
a grow-fast lifestyle

flourishes throughout
this vast region.

The balsa.

But it has to pay a high price
for doing so.

The lightweight wood
that enables it

to grow at such speed
is not strong

and is easily broken.

Few balsas live
longer than 20 years.

This one is approaching the end
of its brief life,

so the time has come for it
to reproduce.

It has used a huge amount
of energy to produce

some of the most extravagant
flowers in the forest

in immense numbers.

Each is the size
of a human hand.

As night falls,

the tree prepares
an enticing treat.

This is a kinkajou,

a kind of fruit-eating
raccoon.

Each flower is filled with
huge quantities

of exceptionally rich nectar,

supercharged with sugar.

Irresistible!

The kinkajous drink so greedily

that they get pollen
all over their faces.

So, as they move from
tree to tree,

they carry pollen with them.

But the balsa
leaves little to chance.

The nectar might appear
to have run out,

but this is just
the first round.

Now the balsa refills
its flowers,

enticing the kinkajous back
to repeat the process...

...seven times a night.

Pollination is complete.

And the kinkajous -
they also get well served,

with over 100 pints of nectar
in just a few weeks.

Both plant and animal do well
out of this arrangement.

But in the tropical world,
that isn't always so.

(BIRDS AND ANIMALS CALL)

Borneo.

Here, on the slopes
of Mount Kinabalu,

live plants that eat animals

using pitcher-shaped leaves
full of water.

Insects are attracted by
the expectation of nectar,

but tumble into the pitcher,

where they are drowned
and absorbed.

On the lower slopes
of the mountain,

a plant grows
that has no leaves at all.

Or even a stem.

All that can be seen is this -

a bud.

It is a parasite.

(RUSTLING)

The rest of its body lies
within the tissues of a liana,

on which it feeds.

After about five years,

the bud finally opens into
a monstrous flower.

It now has only a day or so
in which to be pollinated

before it starts to wither.

Its petals are
the colour of blood.

Their surface is tough
and warty.

It appears to have fur.

Even whiskers and teeth.

At first sight, it might be
mistaken for a dead animal.

This is rafflesia,

the corpse flower.

A metre across, it's
the world's biggest flower.

And this one is a male.

From its centre comes
the pungent odour of death.

It's a scent that might not
appeal to every animal.

But it's very attractive to
carrion flies.

They lay their eggs
on rotting flesh.

(FLIES BUZZ)

The scent lures the fly
deep into the flower

in search of meat.

The fly finds nothing.

The rafflesia, however, has the
fly exactly where it wants it.

It's stuck pollen
to the fly's back.

If this male rafflesia's
strategy is to work,

the fly carrying its pollen
must now visit

a female corpse flower...

...such as this one.

(FLY BUZZES)

Success!

Once pollinated, plants are
able to produce seeds,

the next generation,

but once again, there are
animals all over the forest

that are eager to make
a meal of them.

(BIRDS CALL)

The Malay Archipelago,

a vast tropical world
of 1,000 islands.

It's home to giants -

the tallest trees
in the tropics,

many of which live
for centuries.

They produce seeds
in enormous numbers,

but only do so
when the time is right.

This individual hasn't produced
a single seed

for nearly a decade,

but in the last weeks,
it has become festooned

with more than 10,000 of them.

Each seed has the potential to
produce a giant,

like its parent.

But success will depend...

...on timing.

(SNORTS)

Seed-hunters are gathering.

Bearded pigs.

(GRUNTS)

But these seeds have been
produced by a dipterocarp...

...trees that create
the tropical world's

largest seed nursery.

After years of waiting,

thousands upon thousands
of individual dipterocarps

have synchronised to produce
the next generation,

all at exactly the same time.

(BIRDS CALL)

And now these seeds will face
the dangers below together.

By releasing billions of seeds
all at the same time,

they swamp the pigs
and any other animals

with more than they could
possibly eat.

And that buys time for
some of the seeds to take root

and sprout.

(CRACKLING)

The tree's strategy has worked.

But a seedling will have to
overcome many more dangers

over the years if it, too,
is to become a giant.

And there are many ways
in a tropical forest

by which a tree's life
can be ended

before it reaches its prime.

The northernmost tip
of Australia.

This is the world's
most ancient rainforest.

(BIRDS AND ANIMALS CALL)

(LOW GRUNTS)

Battles between animals
and plants

have raged here
for 180 million years.

(LOW CREAKING)

So the plants have had time
to develop effective defences.

This is a poison arrow tree,

one of the tropical world's
most heavily defended plants.

Its trunk is tall and slippery

and exudes a poisonous sap.

It appears to be
almost invulnerable.

But even so,

just as this individual
reaches maturity,

its life has become endangered.

(BIRDS TWEET)

Each ITIOHSOOH SGGSOH,

it is invaded from above.

It attracts
hundreds of shining starlings.

Its immense smooth trunk makes
its high branches above

a safe place to nest,

but over the years,

this has created
a major problem for the tree.

After feeding, the starlings
return to the nest

to digest their food,

with inevitable consequences.

Every year,

they produce almost a quarter
of a tonne of droppings.

The toxic chemicals
they contain

create a dead zone that
completely surrounds the tree.

The toxins are absorbed
by its roots

and travel up through the trunk
and into every leaf.

(CRASHING)

Branch by branch,

the tree is slowly dying.

It has become a victim
of its own success.

It has been poisoned.

Now a new battle begins...

...one to claim the tree's
dead body

and the vast amount
of nutrients that it contains.

It's a battle that is fought
throughout the natural world...

...involving a group
of organisms

that we rarely notice.

They exist for most of the time

hidden in the leaf litter
and earth

as a network
of fine white threads -

fungL

The threads of competing fungi
envelop their victim's body,

releasing enzymes which digest
the tree's tissues

and unlock the nutrients
within.

There are a million or so
different species of fungi

in the tropics.

Some feed on dead plants.

Others eat them alive.

And some reveal their existence
in an eerily beautiful way.

In Africa, in the Congo,

this is known
as chimpanzee fire.

The mysterious
bioluminescent glow

becomes brighter as the fungus
digests the tree.

When fungi have fed
sufficiently,

they develop
their reproductive organs.

Each can produce
literally billions of spores...

...the tiny particles

that carry the species'
genetic blueprint.

Each spore like this

has the potential
to kill a tree.

(SPORES RUSTLE)

The spores are so light

they can be carried by
the slightest air currents.

At least a billion

float above every square metre
of rainforest.

Recently, it has been
discovered that these spores

do far more than just bring
death and decay.

They are, in fact,

at the very centre

of the rainforest's
life support system.

(WIND WHISTLES)

High in the humid air,

the spores combine
with molecules of water.

(RUMBUNG)

Gradually,
they collect into droplets,

which,
when they are heavy enough,

- fall...
- (THUNDER CRACKS)

...as rain.

Over two-and-a-half metres
of rain falls every year

in a rainforest.

And in the centre of almost
every raindrop,

there is a fungal spore.

The world's rainforests
are the richest

and most dynamic environments
on Earth,

built on complex connections
and relationships.

(BIRDS SQUAWK)

But these connections,

competitive or collaborative,

are now becoming
increasingly fragile.

(THUNDER RUMBLES)

(THUNDER CRASHES)

Today, 70% of all the world's
rainforest plants

grow within a mile of a road
or a clearing

that we have
cut into the forest...

...and this is creating
new battlefields

in the tropical world.

Alien armies of identical
cultivated plants

now stand where thousands
of different species once grew.

We have planted
vast regiments of crops

in order to provide ourselves

with food
and other commodities...

...and the ancient forest
has been reduced

to ever fewer
isolated fragments.

All, however, is not lost.

The fragments
can still be sanctuaries...

...keeping alive the intimate
relationships within them.

This is the seven-hour flower.

The plant produces its flowers
at night.

They open for about seven hours

and then they die.

During that time,

they provide food
for one particular animal.

Underwood's bat feeds almost
exclusively on its nectar.

It is the plant's
primary pollinator.

An individual seven-hour flower

only produces
a small amount of nectar,

so a bat must visit
as many as 300 flowers a night

to find enough food to survive.

And it pollinates them
as it feeds.

But if a patch of forest
becomes too small,

with too few flowers,

the bats will disappear,

and without the bats,
the flowers can't reproduce

and will soon die out.

The partnership is broken.

Life in the forest depends on
countless close relationships,

but they are increasingly
under threat

as forests
become more fragmented.

The solution, of course,

is to join these remaining
fragments together again.

30 years ago,
this forest in Costa Rica

was grazing pasture.

The cattle were removed,

and nature was allowed to
take its course.

This new forest
has become a bridge

that connects several
fragments,

allowing plants and animals

to both renew old connections

and create fresh ones.

Of course,
we urgently need to protect

the healthy forest
that still remains.

But looking forward,

we must take what may well be
our last chance

to re-build
the lost rainforest...

...and preserve the treasures
of the tropical world

for future generations,

and with it,

ultimately protect all life
on this, our green planet.