All language subtitles for Gardeners’ World 2021 S54E28

Hello.
Welcome to Gardeners' World,

and a rather special
Gardeners' World today

because we're going to devote
the whole programme to trees

and celebrate their wonder
and magic and mystery.

And I'm here at Nant y Bedd

which is the creation of
Sue and Ian Mabberley.

And what they've done is
establish this magical garden

set deep in the forest
in the Brecon Beacons.

Coming up on today's programme -

Nick shares his top tips

for choosing the right tree
for your garden.

No matter if your garden
is large or small,

or in the city
or in the countryside,

I reckon there is a tree
to suit virtually every space.

Arit talks with
the environmentalist Al Gore

about the importance of planting
more trees for the planet.

Gardeners can play a key role

by helping to enhance awareness of
the role the natural world plays

in stabilising and protecting
our ecological systems

and the integrity of those systems.

We meet a bonsai enthusiast

who has perfected the ancient art
of creating these living sculptures.

This is a lonicera
that came from a hedge

and it's something that
you can root very, very easily

and look after very easily.

And I meet the world's leading
tree authority, Tony Kirkham,

to discuss the role that
trees play in our ecosystem.

Our native oak plays host
to something like 2,300 species.

It is an incredible tree.

Now, our films from your gardens
in today's programme

are an expression of
your love of trees,

and the first of these
comes from Merseyside.

Hi, my name's Rebecca

and I live just outside of Liverpool
with my husband Ross

and I'd love to give you
a tour some of the trees

that we've got in our garden today.

Our garden isn't a huge garden,

it's 60 foot by 24 foot,

but we've managed to fit in
over 20 trees

so I think it's safe to say
that we love, we love our trees.

Quite possibly my favourite tree
in the garden

has to be
the golden Indian bean trees.

I just love the foliage so much.

They've got these beautiful,
big, heart-shaped leaves

that are tissue-paper-thin

and they're the most
vibrant shade of lime green.

Our golden Indian bean trees
are grafted

which is brilliant
for a smaller garden

as it basically means that
the stem will stay at that height

and only the head of the tree
will grow.

And we're hoping that these trees
will grow together

and form an archway.

Another tree that we love
are the standard ginkgoes

and we actually have
three of these planted

in a pebble trough in the patio,

and we've added some alpines
at the base for some extra interest.

The foliage on these is lovely.

It's such a unique shape,
it's almost got frills.

And in the autumn, the leaves turn
a buttery golden-yellow colour

which just extends
that period of interest.

So, hopefully, you've enjoyed
having a little look around

all of our trees,
and maybe it gave you some ideas

of some trees that you might like
to add to your own garden.

I think Rebecca's garden
looks absolutely fantastic

and it does show you that
you don't need a great big space

to do extraordinary things
using trees in your garden.

Now, recently, I went to visit
a garden, Hergest Croft Gardens,

in Kington in Herefordshire

to meet the great tree expert
Tony Kirkham.

And we walked through the arboretum
there on a very rainy day

to discuss the role of trees in our
gardens, and indeed in our lives.

Tony, I think everybody would agree
that trees are wonderful

but why?

What's wonderful about them?

When we think about the benefits
that trees provide us with,

so, without trees,
we wouldn't be able to breathe.

They take carbon dioxide,
bank it into the tree,

so they make wood from it, store it,
and then give us oxygen in return.

So we desperately need that.

Does it have to be trees?

There are lots of plants that
will do that as well, aren't there?

There are lots of plants,
but the trees are the workhorse.

So, for example, Monty, an oak tree
about 100 to 150 years old,

if we took every leaf off that tree

and laid them side by side
on the ground,

we would cover an area
the size of a football pitch.

And you imagine the work that
that's doing, photosynthesising,

taking in carbon dioxide, and giving
us the oxygen that we breathe -

I think that really puts it
into perspective.

They are incredible machines,
really,

and sometimes we take them
for granted.

One of the things that has become
really topical - and rightly so -

is the role of our gardens
for wildlife. Yes.

Now, I know that trees are
an integral part of that.

But to what extent?
How important are they for wildlife?

It's the habitat, really,
that they provide for wildlife.

So, for example,
our native oak plays host

to something like
2,300 species alone -

that's fungi, lichens, mosses,
insects, mammals, birds.

And of those 2,300,
over 300 - 320 to be precise -

are what we call obligate species,

so they will only live on the oak,
they can't live on anything else.

Trees bring countless benefits
to our world.

But the challenges they're facing
are growing year on year.

Generally speaking, today,
the biggest threats to trees

are changing climate.

So, the seasons seem to be merging,

and we're going away
from four seasons into two.

So autumn merges into winter,

and then spring merges into summer,
and plants get mixed up.

Remember, trees have been around
for millennia,

and over a very short
period of time, you know,

45 years that
I've been working with trees,

that has been a very big change.

Trees need a rest.

So, trees are like you and I.
We need our sleep.

If we don't get our regular sleep
pattern, then we're a bit grumpy,

a bit moody, a bit stressy.

And it's the same with trees -

they need that winter dormancy
just to relax and rest

and get everything back to normal,
ready for the next growing season.

And that rest period is getting
shorter and shorter and shorter.

And then, the growing season
where they have to work

is getting longer and longer.

The fact that our world is
more interconnected than ever

is causing problems for trees.

Well, the main thing now is

the threat from
introduced pests and diseases.

I mean, when I started,
probably the same as you, Monty,

Dutch elm disease was the thing.

We were all terrified of Dutch elm.
Yeah, yeah.

But it was the only one.

Now the oaks are threatened
with acute oak decline,

sudden oak death, and then, in pest
terms, oak processionary moths.

And so the list is growing,
and there's a whole range of pests

and diseases that aren't necessarily
here yet that we don't want.

So what can gardeners do
to mitigate those problems?

The first form of defence really
is prevention.

Not bringing in any plant material
on your travel.

That's... Don't be tempted.

When you go on holiday,
you see an olive or something

and you are tempted to bring
cuttings back, or seeds,

don't do that.

The problems that trees are facing
can seem overwhelming

but we can all play a part
in turning this around.

What should we, as gardeners,
be doing?

We could all help
by planting a tree.

And if you think, if everybody
with a garden planted a tree,

20 million people, 20 million trees,

that would be
a massive step forward.

In terms of wildlife,

there's a general perception
that native trees are better.

I think we should be planting
more diversity, different species.

I mean, look at this tree.
This is from China.

It lives up to its name.

It's Sorbus splendens.

All these berries
will be eaten by birds,

so, even exotic trees
are good for bird species.

And when we go to a nursery,

we should be deciding
what do we want from our tree?

It's usually ornamental attributes,

so, a good bark, good flower,

good fruit,

a nice-shaped leaf, autumn colour.

And if we can tick
all those boxes for a tree,

then that is a really
hard-working tree,

and deserves that position
in the garden.

So let's all plant a tree.

I'll be chatting to Tony
later on in the programme,

talking particularly about the way
trees communicate with each other,

it's absolutely fascinating stuff.

But you may feel that,
with the best will in the world,

you simply can't accommodate a tree
in your garden,

may not even have a garden.

But think again,
because there really is a tree

for every situation in every garden.

There are trees that
you can grow on balconies,

trees that you can grow
in a pot on a windowsill.

And if you want to find out more,
then one of the best places to go

is a flower show.

And a few weeks ago,
Nick went to Chelsea

in search of tree inspiration.

Ideally, every garden
could and should have a tree,

but it's really worth doing
your homework.

Getting the right-sized tree,
the right-sized space

is so important because
you're not just planting for now,

you're planting for the future.

With a huge variety of trees
to choose from, it's a good idea

to consider not only
your climate and soil conditions,

but also your budget,

and how long you're willing to wait
to get that fully matured effect.

With bigger trees,
you're buying time.

But don't be afraid to plant
a sapling and watch it grow -

young trees often establish better.

30 years ago, I started
my first job in horticulture

which was working on a tree nursery,

and I spent that first summer bent
double, budding and grafting trees -

a huge proportion of which
were malus, or crab apples.

They were hugely popular back then,
and they're just as popular today.

And rightly so, because they provide
so many seasons of interest

and they're great for wildlife

as the fruit provides food
through autumn into winter.

There are lots of varieties
to choose from

meaning there's something
for every size of garden.

Some will even grow in containers.

As with any tree, always be sure
to check the ultimate size,

what soil and light requirements
your tree needs,

and you can't go wrong.

Now, this particular cultivar,
Winter Gold,

will go up to about four metres

and it starts out in spring

with a mass of white blooms,
which are brilliant for pollinators.

It then produces these fruits
which are initially green,

and then take on this lovely golden
tone in late summer and into autumn.

Now, they persist well into winter
so they're brilliant food for birds.

But if you can get in there quickly
yourself, then you can harvest them

and make wine or crab apple jelly.

But if you want
an even more compact tree,

it's worth thinking about
a cultivar called Red Jade.

That's a weeping form

and it only goes up to
about two-and-a-half metres.

It's absolutely covered
in glossy red fruit

which also lasts well into winter.

Crab apples are easy to grow.

They'll cope with a bit of shade

but the fruit will ripen even better
in a sunny position.

So it's well worth
having a look around

and seeing which malus
is going to suit your garden.

In my book,
the best small garden trees

are those that provide you with
interest throughout the year.

One of my absolute favourite
small garden trees is this -

it's Rhus typhina.

And this specifically is
a cultivar called Dissecta.

It's called that because you've got

these really sort of
chopped-up fine leaves.

In the ordinary form,
they're solid leaves.

And it's incredibly adaptable,

so it'll grow virtually anywhere
in the UK.

Now it's great small garden tree
because it'll only go to about two

and a half metres tall, but it's
got interest throughout the year.

So you can see the old flower
heads here from last winter

and then the flower heads
that have been produced this year,

and they'll persist all the way
through winter, even when the leaves

have dropped off.

Now the leaves are pretty
much the star of the show.

In fact, I defy you to come up
with a tree

that has better autumn colour
than this.

It's got a fantastic range
of really vibrant red, orange

and yellow leaves that persist
for about three weeks.

It does come with one small
challenge,

and that's down at the
root level.

Its roots are fairly determined
to run and send up new suckers,

so they'll travel out
from the centre and then suddenly

send up a new tree.

A simple way to manage it is to just
put in a barrier underground,

which will prevent those roots
of spreading.

There are plenty of trees that will
grow happily in a container

given the right care, and growing
a tree in a pot means

you can have one almost
anywhere in the garden,

even on a patio or balcony.

If you are looking for a compact,
evergreen statement piece

for a small garden or courtyard,

then I reckon that this is the
tree to go for.

It's Pinus mugo pumillio.

Now, unlike
most of the pines,

which are absolutely vast,
this one is naturally a baby.

In fact, it's known as the Dwarf
Mountain Pine, and this particular

specimen is 50 years old.

But it's something that you can
start yourself at home with a

medium-sized specimen and gradually
train it over the years.

I think it adds that fantastic sort
of oriental look to small spaces.

Like most pines, Pinus mugo isn't
particularly fussy about its soil

type, as long as it isn't heavy
clay.

It will benefit from regular
watering in the hottest of summers

as its roots lie very close
to the surface of the soil.

It has to be said, there's a pretty
fine line between what constitutes

a large shrub and a small tree.

This is a prime example.

It's a brilliant plant.

It's called Heptacodium miconioides.

It's often known
as Seventh Son of the Seventh Son,

and that's because of the way
its flowers are structured.

So you've essentially got a cluster
of six flowers,

with one in the centre.

Now it really is the large shrub
or the tree with it all.

Right now we're in late summer
going into autumn, and it's covered

in massive blooms, which are
absolutely loved by pollinators.

But once the flowers have dropped
those Calluses, those little pink

supports on the back of the flowers
sustain until November or December.

So all this looks like a pink
flowered shrub, then through the

winter you've got these fabulous
sort of ghostly stems.

You can see the bark is peeling
off in beautiful strands.

Now it's genuinely small,
so it'll never get

to more than about four
metres or so high.

And, of course, because it's got
that open quality, it's good

as a host for other plants, things
like bitter clematis, which flower

in the end of autumn
would be absolutely perfect

to grow up through this.

So for an all season large shrub
or small tree,

I reckon Heptacodium miconioides
is the one to try.

One way to maximise your vertical
space and ensure you get the most

from a fruit tree is to grow
them against a wall or a fence.

Espalier apples and pears
are ideal for this.

Now, this particular specimen
is a conference pear

and this is probably about 50
years old.

You can see it's seriously gnarly,
but if you want to grow them

yourselves, you can buy them
pre-trained as a relatively young

tree, two or three years
old. Once they're in the ground,

they will fruit in one to two
years' time,

Or you can just take a tree yourself

and gradually train it over
the years.

Both pears and apples can be grown
in this way, and you can see there's

a basic T framework here from
which all of these spurs emerge.

And it's these spurs that produce
the fruit,

and so they need to be pruned
during the winter

down to about two buds.

And what you'll find is in spring,
they come into bloom,

masses of white flowers, brilliant
for the pollinators.

Then you'll get embryonic fruit
through summer and then harvestable

fruit in the autumn.

You can grow Espaliers in a number
of different ways.

The classic thing is to grow them
against a wall, trained out flat,

but you can equally put them onto a
garden fence or an interesting

way to use them is mid-garden,
so virtually use them

as a screen or a fence.

So if you're looking for a compact
tree that delivers lots of interest

and is productive, then it's
really worth

considering growing Espaliers.

No matter if your garden
is large or small,

or in the city or in the
countryside,

I reckon there is a tree to suit
virtually every space.

I agree with everything Nick says,

but there aren't many gardens that
could accommodate

these Douglas firs.

It's not so much the footprint.

It's how they soar up into the air.

This is about 85 years old, and yet
already it's 150 feet tall.

And there is no other living thing
on the planet that can match it.

Still to come on today's
programme...

Arit chats with the former American
Vice President and environmentalist

Al Gore, about what we can all do
to protect our trees

and his mission
to get us planting more.

Worldwide, there's now a global
effort to plant one trillion trees,

but we have to plant the right kind.

We climb high into the canopy
of a Staffordshire woodland

to explore the very latest
in cutting edge carbon science.

We are taking the laboratory out
into the forest and asking ourselves

how that forest will respond
to the changed atmosphere

that will be all around everybody
by the middle of the century.

And we get a masterclass
in how best to plant a tree,

when Toby visits a North
London school.

I actually have to name it,
I name everything.

Ted? No, it's not a Ted. Aw.

But first, we're going to Ellsbury
to meet a bonsai artist.

The ideal tree will look
like a mature tree

with ideal proportions.

Something that you can stand
underneath, sit around the base

of the trunk and look up into the
leaves.

My name is Harry Harrington,
and I'm a bonsai artist.

When I worked as a gardener
in my twenties, I would see

these trees that the owner
of the garden had.

And they were just saplings in pots,
but I would see them every day

and having this, this tree
in my hand for me

was just an amazing feeling.

And that is the very essence
of bonsai for me

is you have this beautiful living
entity that you can capture

and nurture and look after.

There was a big mystique
about bonsai, and it was seen

as something very unattainable.

But I think in the past 30 or 40
years, particularly in Europe,

we've realised that you can use
very, very common European trees.

In bonsai, we have naturalistic
styles and we have abstract styles

and naturalistic trees is the tree
that you would still see growing

in a field or on the horizon.

Abstract styles would be
more caricatures of trees.

They may have cloud pruning,
or they may be something

that is a thing of beauty,
but doesn't look like a tree

that you would ever actually
see in nature.

If you try and bring a tree inside
for a day or two, that's absolutely

fine, and it's something that's
very traditional for the Japanese

to show their one tree
for a few days.

But if you try and keep a tree
inside on a long term basis,

it will just gradually diminish
in vigour and health.

When we have a branch that's not
pointing in the right direction,

what I'll do is I will coil copper
wire around that branch

and this enables me to place
it exactly where I want to,

within the design of the entire
tree.

I can put bends into the shoots and
I can completely redirect them.

The wire then holds that branch
in its new position until it's set,

which can be anything from a few
weeks to six months later.

Then the wire is cut away.

So when we're designing the tree,
we're designing the branches.

But we also design the roots
and the surface roots,

and they're very important,
something we call the nabari.

And we have various techniques,
including growing a tree on top

of ceramic tile to ensure
that it grows lateral roots

and no plunging roots.

And after four or five years
of growing in the grounds,

you can actually have quite
an impressive nabari build up.

So this is a great piece
of material for a bonsai.

This is boxwood, it's 20,
30 years old.

It's been dug out of the grounds
and it's survived.

It's got a new root system growing.

And the important thing is,
we've got a nice fat trunk

on which to start developing
branches and start putting a design

into this plant.

However ugly it is now,
you could turn it into a beautiful

bonsai in 10, 15 years.

So this is a Lonicera that came
from a hedge

and was just a basic
block of wood.

And it's something that you can
root very, very easily and look

after very easily, and
they create style.

To your right is a privet.

And this again came from a hedge row
as a big lump of wood.

Rooted really easily,

and over 15 years I've developed and
developed it.

And, again, very easy to look
after species.

One of the lovely things
about having a bonsai collection

is you will start to associate some
of your bonsai with different events

in your life,
whether they're good or bad.

You'll remember the times
where things have been a bit

of a struggle and you're gone out
into the garden, worked on the tree

and just being able to relax
and get away from life.

I have one tree that I obtained
the trunk literally the day

before my daughter Alice was born,
and this was 11 years ago.

So Alice's tree has taken
a journey alongside my daughter

growing up, and that gives
it some additional poignancy.

There is also trees that
I have photographed my children

alongside in various stages
of both their development.

And it's lovely to look back and see
how everything sort of grows

together as you nurture them.

So I think when you accomplish
a design in a tree,

particularly after 10 or 15
years,

there is a buzz, it's something
that you've created yourself.

And it can only improve as time goes
on.

And it will outlive me, and my
children and my grandchildren.

Whenever I see bonsai, created
with the same sort of skill

and experience that Harry has shown
in his, I always marvel at the fact

that these are old, mature trees,
sometimes as old as a big oak tree,

but just condensed and
distilled down into miniature.

They really are completely
fascinating.

Earlier in the programme,
I was chatting to Tony Kirkham,

the great tree expert
at Hergest Croft Gardens,

and our talk turned to the way that,
recently, more and more discoveries

are being made about the ways
that trees communicate

with each other.

We've been discovering more and more
about what you might call

the secret life of trees. Mm.

Well, you're absolutely right.

We are learning more about how trees
communicate to each other.

They do talk to each other,
but in a different way

to...to what we do.

First of all, underground,
there's an incredible network

going on between tree and fungi.

There's mycorrhizal fungi that's
connecting all the roots together.

We call it the "wood wide web".

They work together in a symbiotic
relationship, sharing resources.

So the trees are the host,
the fungi helps the tree

and all the resources are switching

from one tree to another and
from the fungi to...to the trees.

So if a tree feels a bit
under the weather,

then the other trees will help it
and bring it back.

I can give you an example.

I went into a redwood forest and saw
an albino redwood, pure white.

Now that tree can't survive
without chlorophyll.

It had zero chlorophyll.

The only way it could have been
growing happily and healthily

is by other trees supporting it.

As well as helping
and nourishing each other,

trees also seem to have developed
early warning systems for dealing

with the threat of certain pests.

I've seen oak trees where they've
been under attack from winter moth,

but when those groups
of caterpillars get too big

or too large for a branch
or for a leaf,

they can reduce respiration,

increase the tannin levels
in the leaf,

so the leaves become very bitter
to the caterpillars.

Then the tree can communicate
to other trees and say,

"You need to shut down and make
your leaves unpalatable

"for these caterpillars."

How they do that is probably
emitting pheromones

through the leaves, so through
smells and taking smells

in through respiration,
electrical impulses and also

through the root system.

You would think that
in survival of the fittest,

individual trees would be trying to
outcompete their neighbours,

not...not to work with them.
Yeah, you would.

But remember in a woodland, Monty,

it's about building a community
that gives them the protection

from winds, from weather, animals,
etc.

So it's about building that family
and that community

that can survive better in numbers,
rather than on their own.

The information that we are
discovering about this

"wood wide web" is endlessly
fascinating and surprising.

What do you think that
we don't yet know about trees?

Where is the research taking us?

Well, it's certainly taken
us into the...to give us a better

understanding of trees, and I think
there's a long way to go yet.

So, for example,
I know there's research being done

on how trees like pines,

when they're under attack
from aphids,

they can send out a scent,
a pheromone that ladybirds pick up.

And that scent is like blood
in the sea to a shark.

It attracts the ladybirds that come
in and then eat the...eat the aphids

and manage the aphids for the pine.

So they're not just communicating
with each other,

they're communicating to insects
and other creatures.

That's right. Yeah. Extraordinary.

There is so much to learn,
really, isn't there,

about how trees work
and this communication?

I was left with so much to think
about from my day with Tony,

but...but certainly this idea of
trees communicating on the ground

and through their leaves
is mind boggling.

And sitting here, you realise
that all these thousands of trees

in the landscape
are all interacting together,

speaking a language which we can
only hear the faintest whispers of.

Now, Arit had
the opportunity to talk

to the former US Vice President, and
lifelong environmentalist, Al Gore,

about the significance
and environmental role of trees.

You're never really very far away
from a tree in the UK.

Whether you're lucky enough
to have them in your garden

or surrounded by them in the park
or countryside,

or pass them when out and about,

trees in all their wonderful,
beautiful forms are everywhere.

And it's easy to take them
for granted.

They are constants and markers
in our lives and can often

be older than us.

In recent decades, we've begun to
understand the importance of trees

and the role they play
in our changing climate.

For former US Vice President Al
Gore - Nobel Peace Prize winner

for informing the world of the
dangers posed by climate change -

getting this message out
has been his lifetime's work.

Al, it's so great to see you,
and thank you for taking the time

to chat with me today.

It's a great honour to be asked
to be on with you.

Clearly, your passion
for this planet is...is clearly

in your blood and I know
that you grew up on a farm.

And I wonder if that's really
where the relationship started

with you in the land?

And what was your connection
to trees?

My childhood had two parts to
it every single year.

There was the concrete of the city
in Washington DC

and then there
was the farm with trees

and pasture and animals
and blue sky.

And it was pretty easy to make
a choice between those two venues.

And I really enjoyed the time
I was able to spend

being closer to nature.

I didn't really think of it
in those terms as a child,

but my earliest lessons
on environmental protection

were from my dad following him
across the farm,

three, four, five, six years old.

And then it was just a hop,
skip and a jump on to climate

when I had a professor in college
who focused my interest on that.

And I can feel it now
when I get back and walk

through the forest
and we have trails here now

through the trees,
and it's just, it's renewing.

Oh, that's fabulous to hear.

And I have planted
10,000 new trees here on the farm.

It's a small amount compared
to what we need worldwide.

There's now a global effort
to plant one trillion trees.

But we have to plant the right
kind and we have to avoid

these monoculture forests
that are just good

for cutting them down, making paper
or cardboard or something.

You don't get the rich web
of biodiversity that you find

in old-growth forests or mature
forests that have multiple species.

In the UK, over half of our nation
are keen gardeners,

and in the last 18 months,

we've had another three million
gardeners join the band

and this is very much about how
we want to know, as gardeners,

what can we be doing?

You can join and support
the organisations

near you that are fighting to
protect natural land and encourage

community leaders to protect
these valued resources.

Whether you're planting a single
tree in your garden or working

to restore biodiversity
across a larger landscape.

That's really good to hear.

And I love the fact that, you know,

you're saying just even that one
tree

makes you part of a bigger
community, which is so important.

What's your take on the fact
of how we are saving

our existing global forests?

It's important to highlight
the incredible efforts of indigenous

communities who serve as land
defenders and so much of the world

and protect forests
around the globe.

Then we should do more to learn
from them about how we can

effectively protect our
planet's ecology.

And gardeners can play a key role
by helping to enhance awareness

of the role the natural
world plays and stabilising

and protecting our ecological
systems

and the integrity of those systems.

I know that you're incredibly busy,
but do you get time to kind of

go out and still
have woodland walks

and how does that make you feel
when you...when you get to do that?

I make time for it, and I just find
it, as I've said before,

calming and renewing.

We know from the science
and from our own feelings

that, when we tune into them,
that being in the forest

and being in nature is good for us.

I am so, so thrilled to have spoken
to you and listened to your insights

and your...your personal thoughts.

So thank you so much, Al.

Thank you, Arit.

I realise that I normally see
trees from the ground up

and peering up at them,

so it's lovely to have the
opportunity to get up here

into the treehouse
and be in the branches,

surrounded by all these leaves.

Nothing else makes
you realise just how many leaves

there are on a large tree.

And every one of these leaves is
playing a role in capturing carbon

and releasing oxygen.

And Frances has been discovering
more about this

via an extraordinary new project.

Hidden in the heart
of the Staffordshire countryside,

something very special is happening.

And when you look up into the
canopy,

you realise this is anything
but a walk in the woods.

This woodland is a site of the
Birmingham Institute of Forest
Research,

known as BIFoR,
a £50 million international project

to detect changes
in a mature woodland,

brought about by the increasing
carbon dioxide in our atmosphere.

Head of the 40-strong team of
scientists working on this ongoing

ten year project is Rob MacKenzie.

Rather than putting plants
into a laboratory,

we are taking the laboratory out
into the forest

and asking ourselves how that forest

will respond to the changed
atmosphere that will be all

around everybody by the middle
of this century.

We used to think about forests
like this as just gently turning

over in a state of balance.

But, of course, then we realised
that we're changing the goalposts.

As far as the forest is concerned,

we have been pushing it and pushing
it through changes in carbon
dioxide,

changes and pollution due to
traffic, power stations and
fertiliser use.

All of those things have been like a
continual set of knocks

to the system.

And so it's a bit much to expect
the system to just continue

to absorb those knocks.
That's what we're worried about.

Each year, across the world,
temperate forests, not too hot,

not too cold, soak up about as much
carbon dioxide as is released

by the EU and UK combined,

carbon dioxide which would
otherwise stay in the atmosphere

and contribute to global warming.

The question is, can they keep doing
it if we keep pushing them

with more and more carbon
dioxide in the atmosphere?

To answer that, Rob and his team
have created an atmosphere

in this semi-natural deciduous
woodland, which experts calculate

reflects that of the year 2050.

It involves taking pure carbon
dioxide, mixing it with air,

piping it up the towers

and releasing it, very carefully,
under computer control,

into the patches
that we want to experience

that future atmosphere.

These trees are being exposed to
just over a third more
carbon dioxide

than they'd be receiving today,

and the first part of the experiment
is trying to understand

what's going on in the canopy
when this happens.

Up here, this is the domain of the
oaks,

and they're dominating the process
of photosynthesis,

which is the start of the whole
chain of reaction

that we're interested in studying.

Photosynthesis is the process

by which CO2 and water,

by the power of sunlight,
are converted into sugar, into food,

and that food powers the growth
of the plants, but also the growth

of every other single living thing
around us in this forest.

Sugar is created through
photosynthesis,

and is the initial store for
carbon from the atmosphere.

The question is, what happens
to the extra sugar created

through the raised levels
of carbon dioxide?

We need to measure almost
everything you can think of.

And so all around this patch,
there are measurements going on.

We're making measurements
of the amount of leaf

up in the canopy,

how much of it falls down
onto the ground.

We're making measurements of the sap
flowing up through the stem

of the tree.
That's what this is, here.

Of course, one of the classic places
that a tree can store carbon

is in its trunk, building wood.

So one of the measurements that
we make is the girth of the tree.

We measure it continuously
using this band.

We then look at all the trees
in each patch, total up how much

they're growing, and what we find
is more growth in the patches

that are getting the extra
carbon dioxide.

So some of the carbon dioxide,
some of the sugar has been put

into growing the girth of the trees.

So, above ground, the raised
carbon dioxide is having the effect

of boosting the size
of the tree trunks.

But what is this sugar hit doing
to the rest of the forest?

A lot of what we're finding
is happening below ground.

That's difficult to see.

One of the ways that we do it
is by putting cameras

into the soil repeatedly
and measuring the same root

as it slowly grows
over the course of a season.

And we're finding
that there is more root.

Those roots are exchanging chemicals
with the fungus

that's around the roots,
trading sugar in order to get

the rest of what they want
for a balanced diet.

So far, what we're seeing
is a positive effect

from increasing carbon dioxide.

We're finding
that there's more of everything

below ground, more life.

While for now, this mature forest
and the plants and fungi in it seem

to be thriving, with carbon dioxide
levels set to rise even further

after 2050, Rob's team don't yet
know if this ecosystem can continue

to respond favourably
to the changed balance of nutrients.

What we find is that the forest
is responding resiliently.

I feel I know the forest well enough
to say it's even responding

valiantly to the push
that we're giving it,

because we are giving it
a very big push.

But however valiant
the response of the forest is,

it can never be enough
to do the hard work

that we should be doing
in reducing fossil fuel emissions.

If we just expect forests
to do all the work for us,

we're just going to be disappointed.

One thing is for sure, our mature
trees are doing an incredible job

in soaking up
unwanted carbon dioxide.

These guardians of our environment
would take hundreds of years

to replace, and we should do
everything we can to protect them,

whether it be in our forests,
parks or gardens.

Doing so could be the key

to ensuring the future
of our planet.

The way that Professor Rob MacKenzie
and his team have set up

that outdoor laboratory
and are using trees to get as much

knowledge and information to help us
all face the problems that lie

ahead of us,
whether we like it or not,

is inspiring and encouraging.

Now, for our last visit
to one of your guns,

we've been sent this film
from Paul Morrison near Morpeth.

Hi, Gardeners' World.

I'm Paul and I live
in Northumberland, I just want

to show you around my garden.

This is a photo that I did a couple
of years ago, and many plants

with evergreens
and little dwarf conifers.

I've planted it quite closely
because I want instant effects,

straight away.

This is part of my back garden.

This has been planted up
a number of years now.

Absolutely just love trees.

But it's trying to find

the right tree
for the right location.

This is called Acer griseum.

Had this one in about 30 year.

It just has an amazing peeling...

..peeling bark.

Quite slow-growing.

And again, amazing autumn colour.

And half up the border,
they're absolutely crammed

with Japanese maples and acers
and...

..is coming through everything.

This is called
the wedding cake cornus,

and it grows up in tiers,
like a wedding cake,

and it gets lovely white flowers on
in the summer

and it gets
the most amazing autumn colour -

it goes like a bright yellow
in the autumn.

A really nice tree
for a small garden.

This tree here is
Betula utilis jacquemontii.

It's really, really lovely
for winter interest.

It's got an amazing bark,
and the pure brilliant white

looks great in a mixed planting,
or a mixed border.

It doesn't get too big,

so it'll grow
in a normal-sized garden.

And I would said
this one is definitely a most.

Hope you've enjoyed the tour
of my garden in Northumberland,

Gardeners' World.
Thank you for watching.

Take care, bye.

Yes, Paul, I did enjoy your garden,

and thank you very much
for sharing it with us.

It's fine to talk about
the importance of planting trees,

but there is a right way to do it,

and certainly it helps

if you plant them
so that they thrive from day one.

And Toby has been to a school
in North London,

where they've been doing
some tree planting, to talk to them

about the trees that they've chosen

and give them some advice
on how best to go about it.

Most schools lucky enough
to have an outdoor space

or playing fields, use them
for social gathering and sports,

and that's great.

However, here
at the Torridge Academy in London,

they use some of their site
for something completely different.

In partnership
with the local charity Grow,

who work with schools
and volunteers,

they're taking their students
from the classroom to the farm

on five acres of land
that's given over

to growing fruit and veg.

Today, we're going to harvest
some cabbages, which are going to go

into the school canteen
and into our weekly box scheme,

so I'm going to show you
how to do it, first of all.

Farm manager Sarah Allen-Jones works
with this and other schools to bring

teaching to the outdoors.

Really nice.

We'll have food tech lessons
on the farm where they'll come

and harvest veg and learn
about seasonality,

and then the next week
they'll cook it.

We have science lessons out here.

We've had lessons on decay
where we look at the compost heap

and turning the compost heap
to see the different levels.

And we also have creative writing
out here as well.

And the idea is that,
over the years,

we'll have every subject
coming out to the farm,

and that it can be
a real learning hub for the school.

Sowing the seeds of ideas,
sowing cabbages,

but also you've got plans
for planting trees. Yes.

Yeah, and that's something
that we...

It was really important to do
with young people,

to show that they can have an impact
on the world.

They can plant something now

and they can come back in ten years'
time and it'll still be there.

As they use their produce
for school meals,

it makes sense for them to plant
fruit trees to add to the menu.

Oh, and we've got some good ones
here.

This one is a pear
called Conference Moors.

It's like
a regular Conference pear -

super reliable, self-fertile,
looks after itself,

but you get a bit more -
the fruit are bigger.

And what I love about pear trees
in the school garden situation

is they flower so early
in spring - they're there

for the early pollinator,

so great for lessons
around what pollination

and insectivorous life.

And then, over here, what's this?
A miracot.

Now, a miracot is an unlikely
marriage between a mirabelle plum,

or a hedgerow plum, and an apricot.

It's as tough as the hedgerow plants
that you see flowering in early

spring, but also has
the lovely flavour of an apricot.

I mean, the fruits are like plums.

What they get from the apricot
is this freestone ability,

which means that when you open them
up, the stone inside doesn't stick

to the flesh, which is always nice.

And there's a hazel. I'd always
recommend having a hazel tree

in a school garden.

This is Tonda Gentile Trilobata.

Now, what makes this so good is
it's an Italian variety,

and it's the one they use for making
those lovely chocolate spreads.

But like all hazels, it does need
a partner to be pollinated.

So a regular hedgerow type
with this is just perfect.

But even if you don't get nuts,

or squirrels steal them all
before you get them,

hazel is so brilliant.

It's such a useful plant
because all the side shoots

and suckers that come off this,

they make such useful building
materials for making wigwams,

arches and, of course, pea sticks
to hold up the cut flowers.

The students are raring to go.

So I'm going to give them
a lesson in tree planting.

What I want you to tell me
is how deep you think that needs

to be planted.
How deep do we need the hole?

I think, like, where it is there.

So we've got the top
of the compost there.

Mark it on the spade.

That is how deep your hole
needs to be.

Yeah, I'll just make this hole
a bit squarer, a bit larger,

cos if it's square,
the roots can get to the corners

and find their way out.
That makes sense.

What do you know about them,
regarding the bees and pollination?

The bee flies in and then, like,
takes the pollen and, like,

rubs it around its back and stuff.

Then the bee goes, and then...

But it like falls off its body

so that it pollinates flowers
on lots of different occasions.

So it's very clever.

Think about this, right?
Back when the time of the dinosaurs,

there were no bees.

There's only conifers,
trees without flowers.

Isn't that mind-blowing? It is.

We've also got apple variety
Hidden Rose,

with a delightful pink flesh.

So why do you think trees are good?

I think trees are good

because, like,
they're just so calming.

And if you just take your time
to just look at them,

then you can just see the beauty
and, like, all the life that's

living in them. It's like...it's
kind of like a big house

for like bugs and like birds.

It's beautiful.

It absorbs all the carbon dioxide

and also it lets out,

like, really clean, fresh air.

So if you're ever by a tree,
you just have to like, smell

all the lovely fresh air.
Sniff it all up. And give tree hugs.

Tree hugs are awesome.

Yeah, the trees give
the best hugs ever. Brilliant.

Now, there is another ingredient
to go on this.

Now, do you know what this is?

It's fungi.

Yeah, it's just got to be in contact
with the roots, and that way

the fungi will go into the roots
and connect with the other fungi

in the field and the rest
of the food.

So that way it gets its nutrients.

It is, yeah, it's sort of
a really complex process.

But the tree, in exchange
for all the fungi, bringing it food,

nutrients and water, gives sugar.

So it's kind of...kind of a trade.
Like a trade. Exactly.

It's important to stake young trees
while they establish.

The wind in the whole country
largely comes from the southwest.

So you always put a stake
on the southwest side of a tree.

OK. Right?

And that way, when you lash the tree
to the stake to protect it

from the wind, the tree falls away
from the woodwork

and doesn't rub against it
and get damaged.

The tree will flourish
if you backfill with soil

and firm it in.

I actually have to name it,
I name everything. Do you? Ted.

No, it's not a Ted.

Do you see Ted in this?

I'm very disappointed in you. Adam.

Yeah, we can name it Adam.
Yeah. Yeah, Adam!

We've gone Adam.

Adam's apple. Very good.

Well, I sat the trees in.
Done a good job on that.

Excellent.

Thank you. Thank you.

Most vital of all,

make sure your tree gets
plenty of water in the first year

while its roots establish.

It's often said
that when you plant a tree,

you do it for your grandchildren,
but today,

well, I've learned the profound
importance of getting

young people involved.

I'll tell you what, with such
inspirational, wonderful young

people coming through,

there's hope for this planet yet.

Of course, it's extra important
that we get children to plant trees

and learn about them
and be interested in them

because it is their world
that trees are going to play

such an important role in.

And if you want to plant trees,

you might like to take part
in the Plant Britain project

that Countryfile has established,
where they're aiming to plant

three quarters of a million trees
over the coming two years,

and you can get all the details
about it from our website.

That's it for today.

And I do hope this has inspired you
to go out and just make the most

of the wonderful trees
we have, wherever you are.

And if you've got a garden,
to plant a tree.

They are wonderful for wildlife.

And from day one, however small
that tree is, I can promise you

they're completely fascinating.

I am back at Longmeadow
next Friday at eight o'clock.

So join me, Patti and Nelly then.

Bye-bye.