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DAVID ATTENBOROUGH:
The relationship between plants
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and humans is extraordinary.
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We've been adapting
to each other
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for as long as
we've been on the planet.
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We rely upon plants
for everything.
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The air we breathe.
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The food we eat.
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Even the water we drink.
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Much of the clothes we wear.
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And in some parts
of the world,
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the very buildings
in which we live.
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But that relationship
is now changing.
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How it changes next will shape
the future of our green planet.
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Some plants have the ability
to live alongside us...
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...even when we make it
extremely difficult
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for them to do so.
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Piccadilly Circus,
in the heart of London.
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It would be difficult
to imagine
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a more hostile place
for a plant.
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And yet, even here,
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plants will find a way.
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Plants like this may seem
to follow us wherever we go.
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We call them -
perhaps a little unkindly -
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weeds.
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In fact, these plants
are pioneers,
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the ones that are most able
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to take advantage
of new habitats,
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even very harsh ones.
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This wall is
at least 100 years old
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and it's like
a sheer cliff face,
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with no sign of soil.
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Ivy-leaved toadflax
grows towards the light,
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with its flowers
facing outwards
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to attract pollinators.
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But now the pods turn
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and grow away from the light,
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00:03:25,748 --> 00:03:29,293
But once they've succeeded
in doing that,
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00:03:29,376 --> 00:03:31,420
and the seed pod
starts to develop,
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its behaviour changes.
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00:03:35,507 --> 00:03:40,054
Now the pods turn and
grow away from the light,
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seeking the darkest place
they can find.
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A crevice, perhaps,
like this one.
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It's all the toadflax needs.
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It can now germinate and
start to produce a new plant.
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Other pioneers have
a different strategy.
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They, instead, distribute
their seeds far and wide
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in great numbers.
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Sow thistles are
masters of this trick.
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Each of its seeds has
a tiny downy parachute
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which will catch
the slightest breeze.
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00:04:44,868 --> 00:04:47,579
And they can travel
extraordinary distances.
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They can rise a mile high
in the sky
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and reach places
hundreds of miles away
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from the parent plant.
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00:05:02,678 --> 00:05:05,306
The seeds only need
to find the tiniest chink...
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...and they can take hold.
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We barely notice
many of these plant invaders.
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But here,
in the heart of Hong Kong,
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strangler fig seeds
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00:05:24,408 --> 00:05:27,745
that landed on a stone wall
generations ago
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have spread their flexible,
branching roots far and wide.
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They can be anchored so firmly
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that they become a part
of the city's architecture.
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00:05:47,723 --> 00:05:51,852
This is, perhaps,
the ultimate weed.
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But there are places where
the extraordinary abilities
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of fig trees have created
a very different relationship
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with human beings.
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(BIRDS CALL)
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Meghalaya,
in northeast India...
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00:06:23,884 --> 00:06:25,636
...a high-altitude plateau
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riven by
dizzyingly steep valleys.
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It's home
to the Khasi people...
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...who've learned how to use
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the remarkable properties
of fig trees
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to help them live
in such difficult country.
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As in Hong Kong,
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the tree's numerous roots
anchor it firmly,
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here, to steep mountainsides.
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00:07:02,881 --> 00:07:07,761
These roots can grow
up to 2.5cm a day.
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00:07:07,845 --> 00:07:10,305
They are unusually strong,
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00:07:10,389 --> 00:07:11,515
flexible
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and can develop
into a multitude of shapes.
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The Khasi persuade them
to provide them with stairs.
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00:07:28,532 --> 00:07:30,826
The monsoon season brings
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00:07:30,909 --> 00:07:33,078
a seemingly insurmountable
chaflenge
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for Khasi communities.
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(THUNDER RUMBLES)
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This is the wettest place
in the world.
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Nearly 30cm of rain can fall
in a day.
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Rivers become lethal torrents,
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dividing communities
from each other.
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This is when the relationship
between fig trees and the Khasi
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00:08:10,199 --> 00:08:12,451
becomes most important.
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They deliberately plant
fig trees near the rivers.
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When they're mature enough
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to have developed
many hanging roots,
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Shining Star Kongthaw
begins working with them.
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He guides the roots
through bamboo tubes
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that are pointed towards
the opposite river bank.
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00:09:14,972 --> 00:09:18,225
These strands will combine
as they grow,
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sharing nutrients
and resources,
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and becoming stronger than
a lone strand could ever be.
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As the years pass,
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the growing roots
become a living bridge.
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As they grow,
they become ever stronger
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and more stable.
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This unusual relationship
has allowed the people here
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to thrive in an otherwise
challenging landscape.
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But there are plants
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that have found
a deeper partnership with us,
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00:10:54,321 --> 00:10:59,201
and, in doing so, have changed
landscapes across the globe.
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00:11:02,829 --> 00:11:05,749
It began over 10,000 years ago
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with plants that we found
especially good to eat.
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00:11:11,838 --> 00:11:16,176
At first, this relationship
created challenges of its own.
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00:11:18,637 --> 00:11:21,223
Many of the ancestral grasses,
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00:11:21,306 --> 00:11:23,934
like these wild oats
from Israel,
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have a trick to ensure
their seeds are planted
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in the perfect place.
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Each seedhead, at the top,
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00:11:33,235 --> 00:11:36,822
carries two long bristles
called awns.
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00:11:38,740 --> 00:11:40,534
When a seed drops
to the ground...
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...these awns do something
truly extraordinary.
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They walk.
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00:12:23,368 --> 00:12:27,706
The awns twist as they dry out
during the day,
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00:12:27,789 --> 00:12:30,667
and then, when they get wet...
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...they untwist.
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Tiny hairs grip
onto the ground,
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keeping the individual
moving forward.
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00:12:50,061 --> 00:12:53,523
In this way, the seeds work
their way along the ground
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00:12:53,607 --> 00:12:57,486
until, eventually, they find
a rock to hide under
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or a crack to drill into.
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This adaptation is useful
for the plant
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but not for us.
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00:13:12,459 --> 00:13:14,044
It's hard to collect seeds
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when they drop off
and walk away.
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00:13:17,923 --> 00:13:21,051
So our ancestors
selected plants
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whose seeds don't drop off,
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don't have legs
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and don't bury themselves
out of reach.
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They also selected
those individuals
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which put their energy into
developing much larger seeds.
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Close relationships like this
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have developed
all over the world...
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...producing the plants
that are now our crops.
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This might seem like a bad deal
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for the plant, but not so.
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00:14:02,259 --> 00:14:04,970
We eat their seeds
but, in return,
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we cherish and cultivate them,
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00:14:08,181 --> 00:14:12,269
and now they are widespread
and far more abundant
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00:14:12,352 --> 00:14:14,563
than their wild ancestors.
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00:14:28,535 --> 00:14:30,245
In the beginning...
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00:14:31,872 --> 00:14:34,875
...the bargain operated
on a small scale.
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Plant, tend,
and harvest by hand
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in small patches.
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00:14:55,812 --> 00:14:59,149
Over time,
these plants produced more food
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00:14:59,232 --> 00:15:02,152
increasingly efficiently...
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...and the partnerships
became more exclusive.
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We started doing more and more
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00:15:16,708 --> 00:15:20,420
for a small number
of chosen species.
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These few persuaded us
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to eliminate
their competitors...
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...cure their diseases,
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poison their enemies...
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...and keep them well watered,
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...even when other species
face drought.
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Fewer and fewer plant species,
like soy, wheat and rice,
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now occupy more and more land.
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So now whole landscapes
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are dominated
by a single species of plant.
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A monoculture.
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This is the Central Valley
of California,
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the biggest orchard
in the world.
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A million acres
of just one type of tree.
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Almonds.
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Each flower, if it's fertilised
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by pollen
from a different almond tree...
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...will produce an almond nut.
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The flowers' patterns and scent
have evolved
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to attract insects
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00:17:07,402 --> 00:17:10,613
and bribe them to do that job
for them.
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00:17:10,697 --> 00:17:13,783
The pollen
doesn't have to move far.
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00:17:13,867 --> 00:17:16,578
It just has to reach
a neighbouring tree.
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00:17:21,082 --> 00:17:25,712
There are about 20,000 flowers
on each tree...
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00:17:30,091 --> 00:17:34,137
...and 140 million trees.
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00:17:36,264 --> 00:17:39,309
That is billions of flowers,
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all calling out at once.
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But here, the beauty
of the blossom is wasted.
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00:17:49,486 --> 00:17:52,238
To make way
for these almond trees,
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the land was, in effect,
wiped clean.
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00:17:58,661 --> 00:18:02,207
Countless wild species
of plants and animals
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were removed, including,
critically, pollinators.
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00:18:09,339 --> 00:18:11,758
So now the flowers need help,
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00:18:11,841 --> 00:18:13,760
and lots of it.
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(MOTOR HUMS)
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00:18:25,688 --> 00:18:27,607
(FORKLIFT WHIRS)
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00:18:31,778 --> 00:18:33,238
(BOARDS SCRAPE)
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(BUZZING)
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40 billion honeybees...
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...trucked in from all over
the United States.
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00:19:05,687 --> 00:19:08,898
The orchard is only in bloom
for a few weeks,
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00:19:08,982 --> 00:19:13,528
so the almonds need the bees
to get to work immediately.
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00:19:29,627 --> 00:19:33,965
Each bee can visit
thousands of blossoms a day.
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00:19:36,176 --> 00:19:39,179
And while they take
most of the pollen they collect
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00:19:39,262 --> 00:19:40,638
back to the hive,
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00:19:40,722 --> 00:19:45,518
they also drop some pollen
at each stop.
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00:19:45,602 --> 00:19:46,811
And so, with luck,
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00:19:46,895 --> 00:19:51,149
the flowers are
all eventually fertilised.
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00:19:52,275 --> 00:19:54,652
Day after day.
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00:19:54,736 --> 00:19:57,197
The process is repeated.
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Flower after flower.
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00:20:18,843 --> 00:20:21,095
Tree after tree.
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00:20:41,866 --> 00:20:46,746
By the time the petals fall,
two and a half trillion flowers
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00:20:46,829 --> 00:20:49,082
have been
successfully pollinated
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00:20:49,165 --> 00:20:51,251
and will now grow into
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00:20:51,334 --> 00:20:54,003
two and a half trillion
almonds.
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00:20:56,214 --> 00:21:00,802
This type of intensive,
streamlined agriculture
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00:21:00,885 --> 00:21:04,472
produces amazingly high yields.
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00:21:07,850 --> 00:21:11,229
But monocultures are fragile.
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00:21:12,730 --> 00:21:14,482
While they can function
effectively
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00:21:14,565 --> 00:21:16,609
when conditions remain stable,
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00:21:16,693 --> 00:21:19,112
it only takes a small change
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00:21:19,195 --> 00:21:22,407
to create catastrophe.
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00:21:36,254 --> 00:21:38,423
Lodgepole pine.
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00:21:39,924 --> 00:21:42,135
A very valuable timber tree
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00:21:42,218 --> 00:21:45,263
grown extensively
in Western Canada.
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00:21:48,016 --> 00:21:50,476
Millions of acres
of the same species,
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00:21:50,560 --> 00:21:52,979
all the same age
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00:21:53,062 --> 00:21:55,523
and the same size.
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00:21:58,026 --> 00:22:00,320
For centuries,
lodgepole forests
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00:22:00,403 --> 00:22:03,740
have lived in a natural balance
with their enemies,
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00:22:03,823 --> 00:22:06,784
including this one.
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00:22:08,119 --> 00:22:09,996
The mountain pine beetle.
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00:22:13,916 --> 00:22:18,588
In summer, female beetles start
hunting for a suitable nursery
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00:22:18,671 --> 00:22:20,882
in which to lay their eggs.
235
00:22:29,265 --> 00:22:33,019
The ideal site is a mature
lodgepole pine,
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00:22:33,102 --> 00:22:37,190
with bark thick enough
to feed a female's brood
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00:22:37,273 --> 00:22:39,359
and, critically,
to protect them
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00:22:39,442 --> 00:22:41,986
from the bitter cold
of the coming winter.
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00:22:48,409 --> 00:22:50,244
Once under the bark,
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00:22:50,328 --> 00:22:53,122
she tunnels upwards...
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00:22:56,292 --> 00:22:58,753
...laying her eggs as she goes.
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00:23:03,674 --> 00:23:05,176
A single female beetle
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00:23:05,259 --> 00:23:08,679
can lay 100 eggs in a season.
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00:23:24,570 --> 00:23:25,822
When the larvae hatch,
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00:23:25,905 --> 00:23:30,118
they grow by feeding
on the inside of the bark.
246
00:23:31,244 --> 00:23:34,122
As they do,
they damage the channels
247
00:23:34,205 --> 00:23:36,833
that transport water
and nutrients
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00:23:36,916 --> 00:23:39,043
between the roots and needles.
249
00:23:53,224 --> 00:23:54,517
For centuries,
250
00:23:54,600 --> 00:23:58,646
the freezing northern winters
killed the majority of larvae,
251
00:23:58,729 --> 00:24:02,567
so tree and beetle
remained in balance,
252
00:24:02,650 --> 00:24:05,945
but now,
with the climate changing,
253
00:24:06,028 --> 00:24:09,949
the winters aren't cold enough
to control the beetle numbers.
254
00:24:12,827 --> 00:24:14,662
Needles turning red
255
00:24:14,745 --> 00:24:17,999
are a sure sign
that the trees are dying.
256
00:24:27,175 --> 00:24:31,220
The beetle plague spreads like
wildfire across a landscape
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00:24:31,304 --> 00:24:36,517
covered by a monoculture
of similarly vulnerable trees.
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00:24:39,187 --> 00:24:42,231
Since the first mass outbreak
40 years ago,
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00:24:42,315 --> 00:24:45,318
trillions of trees
in North America
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00:24:45,401 --> 00:24:48,696
have been killed
by the mountain pine beetle.
261
00:24:54,619 --> 00:24:58,164
Loss of plant diversity
makes any habitat
262
00:24:58,247 --> 00:25:01,876
more vulnerable
to changing conditions.
263
00:25:03,669 --> 00:25:06,339
Now, with climate changing
so fast,
264
00:25:06,422 --> 00:25:11,344
we're losing plant diversity
just when we need it the most.
265
00:25:13,971 --> 00:25:18,643
Two out of five plants
are now facing extinction.
266
00:25:20,520 --> 00:25:24,732
The loss of any one species
is in itself tragic.
267
00:25:26,317 --> 00:25:28,861
But perhaps more importantly
268
00:25:28,945 --> 00:25:31,280
each lost species erodes
269
00:25:31,364 --> 00:25:34,283
the stability
of a whole ecosystem.
270
00:25:35,952 --> 00:25:40,748
And that should be
of great concern for all of us.
271
00:25:49,131 --> 00:25:52,134
We need an insurance policy.
272
00:25:53,719 --> 00:25:56,973
A hedge against extinction.
273
00:25:59,141 --> 00:26:02,812
This is Kew's
Millennium Seed Bank.
274
00:26:05,106 --> 00:26:08,693
Packets of seeds of many kinds
275
00:26:08,776 --> 00:26:12,029
arrive here
from all over the world.
276
00:26:17,868 --> 00:26:20,621
Some, indeed,
have gone extinct
277
00:26:20,705 --> 00:26:23,291
since their seeds arrived here.
278
00:26:23,374 --> 00:26:26,043
But here, at least,
those seeds are safe.
279
00:26:30,381 --> 00:26:33,509
When they arrive,
they're processed
280
00:26:33,593 --> 00:26:36,637
and sealed into airtightjars.
281
00:26:40,224 --> 00:26:42,602
Seeds are then
brought underground
282
00:26:42,685 --> 00:26:45,855
to be stored in a vault
like this one,
283
00:26:45,938 --> 00:26:48,274
at minus-20 degrees centigrade.
284
00:26:55,823 --> 00:26:57,533
Since the bank was founded,
285
00:26:57,617 --> 00:27:01,370
two billion seeds,
from 40,000 different species,
286
00:27:01,454 --> 00:27:04,874
have been brought
and stored here.
287
00:27:09,128 --> 00:27:12,381
Seed banks have been
founded all over the world
288
00:27:12,465 --> 00:27:14,717
to preserve the genetic legacy
289
00:27:14,800 --> 00:27:17,053
of the world's plants.
290
00:27:21,849 --> 00:27:23,434
This bank aims to store seeds
291
00:27:23,517 --> 00:27:26,103
that urgently need
conservation
292
00:27:26,187 --> 00:27:28,481
from as many species
as possible.
293
00:27:33,653 --> 00:27:36,364
Because a seed contains
everything it needs
294
00:27:36,447 --> 00:27:39,283
to start a new plant...
295
00:27:40,743 --> 00:27:42,370
...each and every one of them
296
00:27:42,453 --> 00:27:44,497
represents
a little grain of hope.
297
00:27:49,794 --> 00:27:53,756
Hope that one day
we will make it possible
298
00:27:53,839 --> 00:27:56,008
for the seeds
of these rarities
299
00:27:56,092 --> 00:27:57,885
to grow in the wild once again.
300
00:28:03,432 --> 00:28:06,060
The seed bank
certainly gives us options
301
00:28:06,143 --> 00:28:10,523
when a species becomes rare
or even extinct.
302
00:28:17,154 --> 00:28:19,865
But around the world,
people are trying ways
303
00:28:19,949 --> 00:28:22,827
to keep natural plant
populations healthy
304
00:28:22,910 --> 00:28:24,787
where they should be -
305
00:28:24,870 --> 00:28:26,914
in the wild.
306
00:28:35,756 --> 00:28:37,800
Hawaii.
307
00:28:40,886 --> 00:28:44,181
90% of the plant species here
308
00:28:44,265 --> 00:28:47,643
are found nowhere else
in the world.
309
00:28:52,898 --> 00:28:55,359
Many are threatened
by a plant invader
310
00:28:55,443 --> 00:28:58,529
called miconia.
311
00:29:01,657 --> 00:29:04,368
It was brought
to the island of Maui
312
00:29:04,452 --> 00:29:07,079
in the '70s
as an ornamental plant.
313
00:29:08,873 --> 00:29:11,709
In its native Mexico,
it grows in balance
314
00:29:11,792 --> 00:29:14,503
with a rich variety
of predators, competitors
315
00:29:14,587 --> 00:29:16,464
and diseases.
316
00:29:23,179 --> 00:29:26,640
It grows taller than most
Hawaiian native vegetation,
317
00:29:26,724 --> 00:29:29,769
and little can grow beneath it.
318
00:29:39,320 --> 00:29:40,988
On the island of Maui,
319
00:29:41,071 --> 00:29:42,782
with nothing
to keep it in check,
320
00:29:42,865 --> 00:29:46,619
it creates
a stifling monoculture.
321
00:29:49,872 --> 00:29:51,916
Miconia, it would appear,
322
00:29:51,999 --> 00:29:55,169
is doing very well for itself.
323
00:29:59,381 --> 00:30:03,469
But today, it's under attack.
324
00:30:07,264 --> 00:30:10,476
On level ground,
a single dedicated team
325
00:30:10,559 --> 00:30:14,355
can keep miconia in check.
326
00:30:22,112 --> 00:30:23,948
But, unfortunately,
327
00:30:24,031 --> 00:30:25,866
this plant can spread to places
328
00:30:25,950 --> 00:30:28,744
impossible for people
to reach on foot.
329
00:30:36,085 --> 00:30:38,337
Just one plant can produce
330
00:30:38,420 --> 00:30:41,048
around ten million seeds
a year -
331
00:30:41,131 --> 00:30:44,927
enough to cover
this entire landscape.
332
00:30:46,804 --> 00:30:49,056
With so much at stake,
333
00:30:49,139 --> 00:30:52,434
the team have come up
with an extraordinary plan.
334
00:31:38,689 --> 00:31:42,109
It's too dangerous
to land here.
335
00:31:45,029 --> 00:31:47,239
But they don't need to.
336
00:31:54,121 --> 00:31:55,873
A marksman with great skill
337
00:31:55,956 --> 00:32:00,336
can shoot the miconia
with paintballs full...
338
00:32:00,419 --> 00:32:02,463
...of herbicide.
339
00:32:05,466 --> 00:32:09,637
A perfect shot
is one that hits the stem,
340
00:32:09,720 --> 00:32:14,016
so ensuring that the herbicide
spreads throughout the plant.
341
00:32:28,197 --> 00:32:30,532
The method is so precise
342
00:32:30,616 --> 00:32:33,911
that with careful flying
and accurate aim,
343
00:32:33,994 --> 00:32:35,955
they can kill the intruders...
344
00:32:37,039 --> 00:32:40,334
...without damaging
any wild plants.
345
00:33:13,283 --> 00:33:15,995
Destroying alien invaders
346
00:33:16,078 --> 00:33:19,206
is not the only way to help
the native plants here.
347
00:33:21,709 --> 00:33:23,669
(BIRDSONG)
348
00:33:27,589 --> 00:33:32,469
This is Waikamoi Preserve,
the last surviving fragment
349
00:33:32,553 --> 00:33:34,847
of a high-altitude
Hawaiian rainforest...
350
00:33:36,306 --> 00:33:39,893
...and home to one of
the world's rarest plants.
351
00:33:43,355 --> 00:33:45,399
Holokea.
352
00:33:47,901 --> 00:33:52,364
There are only 57 fully grown
individuals left in the wild.
353
00:33:56,994 --> 00:34:01,165
Their peculiar flowers evolved
to suit the beak of a bird
354
00:34:01,248 --> 00:34:05,210
found only in Hawaii -
the 'i'iwi.
355
00:34:07,838 --> 00:34:09,631
The bird is now so rare itself
356
00:34:09,715 --> 00:34:13,761
that today these partners
seldom, if ever, meet.
357
00:34:16,805 --> 00:34:20,059
So the chances of holokea
getting pollinated
358
00:34:20,142 --> 00:34:21,769
are very slim.
359
00:34:23,270 --> 00:34:28,609
But a strange new partnership
might just save it.
360
00:34:42,706 --> 00:34:45,292
Conservationist
Hank Oppenheimer
361
00:34:45,375 --> 00:34:46,668
knows where to find
362
00:34:46,752 --> 00:34:49,963
every one
of the last 57 plants,
363
00:34:50,047 --> 00:34:53,926
and he returns every year
to act as their pollinator.
364
00:35:14,446 --> 00:35:17,407
Hank collects the pollen
from the male flower
365
00:35:17,491 --> 00:35:22,037
and dusts it onto a female
flower of a different plant.
366
00:35:25,082 --> 00:35:27,584
He's currently
their life support,
367
00:35:27,668 --> 00:35:31,463
but his goal is for holokea
to thrive without him.
368
00:35:33,507 --> 00:35:35,259
So before he leaves,
369
00:35:35,342 --> 00:35:38,679
he plays the call
of the 'i'iwi bird.
370
00:35:38,762 --> 00:35:41,765
(BIRD CALLING)
371
00:35:52,192 --> 00:35:56,572
Hank hopes the sound
will attract the living birds,
372
00:35:56,655 --> 00:35:59,449
and, if they come,
that they will reconnect
373
00:35:59,533 --> 00:36:01,285
with the last holokea
374
00:36:01,368 --> 00:36:04,913
and rekindle
their vital relationship.
375
00:36:07,040 --> 00:36:10,335
(BIRDS CALLING)
376
00:36:18,760 --> 00:36:23,348
We need to act
not only in the wild places,
377
00:36:23,432 --> 00:36:26,476
but even in those
where we live
378
00:36:26,560 --> 00:36:28,312
and where we farm.
379
00:36:31,398 --> 00:36:34,067
(WATER RUNNING)
380
00:36:38,197 --> 00:36:40,032
Like much of the world,
381
00:36:40,115 --> 00:36:43,619
Kenya is losing thousands
of native trees annually,
382
00:36:43,702 --> 00:36:49,124
ones that local people rely on
for so much, especially fuel.
383
00:36:52,961 --> 00:36:54,922
But here,
people have come up
384
00:36:55,005 --> 00:36:56,924
with an ingenious way
to reverse
385
00:36:57,007 --> 00:36:59,468
some of that loss around them.
386
00:36:59,551 --> 00:37:02,346
(MACHINERY WHIRRING)
387
00:37:08,227 --> 00:37:10,938
At a factory
in the outskirts of Nairobi,
388
00:37:11,021 --> 00:37:15,442
workers collect and sort
waste charcoal dust.
389
00:37:21,156 --> 00:37:24,409
The seeds of carefully selected
native trees...
390
00:37:25,702 --> 00:37:28,413
...are mixed with the dust.
391
00:37:30,123 --> 00:37:35,170
This carbon coat will protect
the seeds from hungry animals
392
00:37:35,254 --> 00:37:36,964
until the rains arrive.
393
00:37:47,391 --> 00:37:50,394
These are seed balls.
394
00:38:05,075 --> 00:38:07,077
In the village of Kibwezi,
395
00:38:07,160 --> 00:38:10,289
acacia trees
are becoming scarce,
396
00:38:10,372 --> 00:38:12,541
cut down
by previous generations
397
00:38:12,624 --> 00:38:15,210
to make charcoal.
398
00:38:15,294 --> 00:38:17,421
(CHILDREN CHATTERING)
399
00:38:36,231 --> 00:38:38,734
But the students at this school
400
00:38:38,817 --> 00:38:42,821
make forest restoration
child's play.
401
00:39:01,548 --> 00:39:04,926
The nutrients
in the dissolving char dust
402
00:39:05,010 --> 00:39:08,638
will give each little seed
a good start.
403
00:39:14,978 --> 00:39:18,565
If only a handful of
these seeds grow into a tree,
404
00:39:18,648 --> 00:39:21,818
the effort has been
well worth it.
405
00:39:21,902 --> 00:39:24,905
Every mature acacia tree
can itself
406
00:39:24,988 --> 00:39:29,242
produce
thousands of seeds a year.
407
00:39:33,789 --> 00:39:37,209
13 million seed balls
have been distributed
408
00:39:37,292 --> 00:39:39,711
in Kenya alone.
409
00:39:41,046 --> 00:39:45,300
And the methods
by which they are dispersed...
410
00:39:48,387 --> 00:39:52,891
...are ever more inventive,
to say the least.
411
00:40:07,239 --> 00:40:10,826
This technique is being
repeated around the globe.
412
00:40:13,995 --> 00:40:19,167
People are choosing seeds
of local native plants,
413
00:40:19,251 --> 00:40:22,587
giving them
a little initial help,
414
00:40:22,671 --> 00:40:24,673
and bringing
some wild plants back
415
00:40:24,756 --> 00:40:27,300
into the world around them.
416
00:40:35,392 --> 00:40:37,060
For those wild plants
that we use,
417
00:40:37,144 --> 00:40:39,980
is it possible to take
what we need
418
00:40:40,063 --> 00:40:43,024
without damaging
whole ecosystems?
419
00:41:07,299 --> 00:41:10,427
This plateau in
the Highlands of Ethiopia
420
00:41:10,510 --> 00:41:13,138
is covered by
an extraordinary plant.
421
00:41:17,309 --> 00:41:19,853
Guassa, a grass
uniquely adapted
422
00:41:19,936 --> 00:41:22,022
to thrive at high altitudes
423
00:41:22,105 --> 00:41:23,940
on the equator.
424
00:41:29,070 --> 00:41:31,072
Its blades contain silica,
425
00:41:31,156 --> 00:41:33,116
which makes it very tough
426
00:41:33,200 --> 00:41:37,037
and therefore very valuable
to the people who live here.
427
00:41:46,129 --> 00:41:47,297
Among other things,
428
00:41:47,380 --> 00:41:51,801
it's an essential
building material.
429
00:41:59,351 --> 00:42:04,064
It would be only too easy
to use too much.
430
00:42:08,902 --> 00:42:10,695
But here, people understand
431
00:42:10,779 --> 00:42:13,114
that their lives
and livelihoods
432
00:42:13,198 --> 00:42:15,784
depend on guassa thriving.
433
00:42:21,248 --> 00:42:23,667
They don't cultivate guassa.
434
00:42:25,794 --> 00:42:28,964
But instead,
for over 400 years,
435
00:42:29,047 --> 00:42:31,675
they have protected the area...
436
00:42:33,134 --> 00:42:37,222
...making sure no-one harvests
more than the natural grassland
437
00:42:37,305 --> 00:42:39,391
can sustain.
438
00:42:50,777 --> 00:42:53,488
This approach means
the people get a resource
439
00:42:53,572 --> 00:42:54,864
that will endure.
440
00:43:01,663 --> 00:43:05,250
But they're not the only ones
who benefit from this approach.
441
00:43:09,045 --> 00:43:10,505
Rare animals,
442
00:43:10,589 --> 00:43:12,007
such as the gelada,
443
00:43:12,090 --> 00:43:14,050
the world's only
grass-eating monkey,
444
00:43:14,134 --> 00:43:15,218
thrive here.
445
00:43:18,680 --> 00:43:21,891
And the natural variety of
plants in this alpine community
446
00:43:21,975 --> 00:43:24,352
also thrive.
447
00:43:30,817 --> 00:43:34,237
By carefully controlling
how much grass they harvest,
448
00:43:34,321 --> 00:43:37,574
the people of Guassa
have found a balance
449
00:43:37,657 --> 00:43:39,909
between the plants they use
450
00:43:39,993 --> 00:43:41,828
and those they don't.
451
00:43:50,420 --> 00:43:53,006
Globally, can humanity
find a new balance
452
00:43:53,089 --> 00:43:55,467
between wild plants
453
00:43:55,550 --> 00:43:58,178
and those
we have domesticated?
454
00:44:00,096 --> 00:44:02,515
Around half the usable land
on Earth
455
00:44:02,599 --> 00:44:06,311
is taken up by agriculture.
456
00:44:06,394 --> 00:44:09,272
Do we really need that much?
457
00:44:09,356 --> 00:44:10,940
Maybe not.
458
00:44:11,024 --> 00:44:12,901
(CATTLE BELLOW)
459
00:44:12,984 --> 00:44:14,861
It's a remarkable fact,
460
00:44:14,944 --> 00:44:18,948
that around 80%
of all cultivated land
461
00:44:19,032 --> 00:44:22,994
is used for raising livestock
for us to eat.
462
00:44:27,123 --> 00:44:29,250
Raising animals can
be a sustainable way
463
00:44:29,334 --> 00:44:32,962
to create food,
but in many places,
464
00:44:33,046 --> 00:44:35,590
plants can produce
the same amount of protein
465
00:44:35,674 --> 00:44:39,928
on a fraction of the land
that animals need.
466
00:44:42,889 --> 00:44:44,974
What could it mean
for wild plants
467
00:44:45,058 --> 00:44:47,936
if the global balance
between plant eating
468
00:44:48,019 --> 00:44:50,313
and meat eating shifted?
469
00:44:52,357 --> 00:44:54,192
It may sound odd,
470
00:44:54,275 --> 00:44:56,820
but the more plants we eat,
471
00:44:56,903 --> 00:45:00,073
the more space we can make
for wild plants.
472
00:45:05,620 --> 00:45:08,456
Remarkably,
it's possible to restock
473
00:45:08,540 --> 00:45:12,752
even highly degraded land
with wild plants.
474
00:45:19,718 --> 00:45:22,178
In Brazil, the needs
of cattle ranching
475
00:45:22,262 --> 00:45:25,056
drive most deforestation.
476
00:45:31,813 --> 00:45:35,859
30 years ago, the owners
of one former cattle ranch
477
00:45:35,942 --> 00:45:40,363
wanted to restore their land
to the Atlantic rainforest
478
00:45:40,447 --> 00:45:42,824
that once covered it.
479
00:45:45,076 --> 00:45:48,037
They had no idea
if it could be done.
480
00:45:49,748 --> 00:45:52,333
The land was so bare
and eroded.
481
00:45:54,961 --> 00:45:56,838
But they were determined
to try.
482
00:45:59,132 --> 00:46:00,675
First, they cleared
483
00:46:00,759 --> 00:46:03,803
the introduced
African cattle grasses,
484
00:46:03,887 --> 00:46:05,722
invasive plants
that outcompete
485
00:46:05,805 --> 00:46:07,682
most of the native plants.
486
00:46:15,940 --> 00:46:18,568
The grasses were replaced
by seedlings
487
00:46:18,651 --> 00:46:20,361
grown from seeds gathered
488
00:46:20,445 --> 00:46:24,240
in nearby remnants
of Atlantic rainforest.
489
00:46:32,791 --> 00:46:36,252
The Earth Institute,
or lnstituto Terra,
490
00:46:36,336 --> 00:46:39,088
as the ranch is known now,
491
00:46:39,172 --> 00:46:41,758
was encouraged by early success
492
00:46:41,841 --> 00:46:44,636
and expanded its scope
and ambition.
493
00:47:03,404 --> 00:47:07,325
In five years,
trees covered the land again.
494
00:47:08,910 --> 00:47:10,703
And within ten, it was clear
495
00:47:10,787 --> 00:47:14,123
something remarkable
was happening.
496
00:47:17,126 --> 00:47:19,671
(BIRDSONG)
497
00:47:31,516 --> 00:47:33,810
(THUNDER RUMBLES)
498
00:47:33,893 --> 00:47:36,145
When rain falls,
499
00:47:36,229 --> 00:47:39,899
it now no longer
simply runs off the land,
500
00:47:39,983 --> 00:47:41,484
leaving it parched.
501
00:47:45,280 --> 00:47:48,575
Instead,
it clings to the plants,
502
00:47:48,658 --> 00:47:51,244
to every root, stem and leaf...
503
00:47:53,663 --> 00:47:57,625
...and then slowly filters
to the forest floor.
504
00:48:00,587 --> 00:48:03,840
And so previously dry streams
505
00:48:03,923 --> 00:48:07,302
burst into life
for the first time in decades.
506
00:48:13,141 --> 00:48:16,144
The Institute never introduced
animals or plants
507
00:48:16,227 --> 00:48:18,271
other than the trees.
508
00:48:23,860 --> 00:48:27,238
The animals came back
on their own.
509
00:48:30,783 --> 00:48:32,368
Small ones came first.
510
00:48:50,303 --> 00:48:52,055
And then, very recently,
511
00:48:52,138 --> 00:48:55,224
camera traps left in the forest
512
00:48:55,308 --> 00:49:00,688
captured images beyond
the hopes of everyone involved.
513
00:49:04,108 --> 00:49:06,235
A maned wolf.
514
00:49:07,403 --> 00:49:09,322
An animal that is being driven
515
00:49:09,405 --> 00:49:13,117
from its native habitat
by deforestation,
516
00:49:13,201 --> 00:49:15,870
drawn to its favourite plant,
517
00:49:15,954 --> 00:49:18,831
the wolf fruit tree.
518
00:49:22,043 --> 00:49:23,586
Not only that...
519
00:49:23,670 --> 00:49:26,089
(HIGH-PITCHED CALLS)
520
00:49:29,050 --> 00:49:31,260
...a puma.
521
00:49:34,138 --> 00:49:36,349
With cubs!
522
00:49:45,942 --> 00:49:50,780
The arrival of these precious
top predators and their young
523
00:49:50,863 --> 00:49:52,407
shows what can happen
524
00:49:52,490 --> 00:49:56,119
when we make space
for wild plants.
525
00:50:01,582 --> 00:50:04,961
We have for centuries
robbed wild plants
526
00:50:05,044 --> 00:50:08,798
of the space and time
they need to thrive.
527
00:50:10,466 --> 00:50:14,595
That has certainly not been
to their benefit.
528
00:50:16,347 --> 00:50:20,143
Nor, ultimately, is it to ours.
529
00:50:25,982 --> 00:50:31,112
Our relationship with plants
has changed throughout history.
530
00:50:31,195 --> 00:50:33,114
And now it must change again.
531
00:50:36,492 --> 00:50:38,578
We must now work with plants...
532
00:50:40,246 --> 00:50:43,750
...and make the world
a little greener,
533
00:50:43,833 --> 00:50:46,127
a little wilder.
534
00:50:49,839 --> 00:50:54,135
If we do this,
our future will be healthier,
535
00:50:54,218 --> 00:50:57,263
and safer, and happier.
536
00:51:03,061 --> 00:51:07,398
Plants are, after all,
our most ancient allies.
537
00:51:11,152 --> 00:51:16,824
And, together, we can make this
an even greener planet.
39839
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