Forests The Great British Winter

The British countryside in winter.

Cold, unforgiving, bleak.

As temperatures plunge, the skies open,

the winds rage and the light fades early.

This winter, we've seen extremes of weather.

Mild, wet and freezing cold.

Conditions that challenge both wildlife

and the people trying to survive here.

In this series, I'm going to get under the skin of our British winter

to reveal its hidden secrets.

I'll be exploring five of our most extreme winter landscapes.

I'll be including some of my BBC colleagues' experiences

from over the years.

Together, we'll reveal what's really out there

during our most challenging season.

Today, I'll be looking at our woodlands.

Discovering why winter is the time to grow a forest.

-Lovely stuff.

-Give it a wee taste, just to make sure it's...

-Nice and firm.

-Nice and firm, that's right.

'Finding out how the re-introduced British beavers

'survive the harsh weather.'

It's my first up-close encounter with a wild beaver.

'And using the latest military hardware

'to monitor Britain's largest terrestrial mammal

'under the cover of darkness.'

Oh, there's a deer already! There's a few!

Welcome to The Great British Winter.

The British Isles boast an extraordinary variety of habitats.

From snow-capped mountains

to huge networks of rivers and lakes.

Our vast swathes of woodland

range from ancient oak forests to dense coniferous plantations.

Coastal birch and beech to planted poplar avenues.

Altogether, Britain's woodlands cover an area

almost one-and-a-half times the size of Wales

and form a defining part of our landscape.

Today, I'm in Knapdale Forest in Argyll

on the west coast of Scotland.

In winter, it's all peaceful and quiet,

but a couple of months ago, this landscape

would have been bustling with activity.

Knapdale Forest covers 48,000 acres

and is home to a huge diversity of woodland animals.

As winter approaches, here and in forests all across Britain,

these animals race to collect enough food

to see them through the lean times ahead.

Small mammals such as dormice

find warm, safe places underground to hibernate.

Sleeping up to six months during the coldest weather

and surviving off the body fat they accumulated during the summer.

Other animals, such as badgers, which don't hibernate,

spend long periods of time sheltering.

Blocking up their sets and sitting out the harshest weather.

There is one animal that takes refuge from these conditions

amongst the forest trees that I'm hoping to see.

It's Britain's largest terrestrial mammal, the red deer.

During the winter, many of these iconic animals

congregate in woodlands, forming dense groups.

With much of the ground frozen or under snow, food can be scarce.

And this can be a difficult time of year,

when mortality rates are at their highest.

Despite this, in Scotland, red deer populations are increasing.

With no natural predators to limit their numbers,

they have to be monitored.

And there is one group responsible for doing just that.

Scottish Natural Heritage take advantage of the winter

to monitor their red deer, keeping track of their numbers.

And even though it's dark and leathering down with rain,

I'm on my way to join them now for one of their deer counts.

The deer are more active at night, so this is best time to check them.

And a tough job falls to Jamie Hammond and Jimmy Irvine.

-Evening, gents.

-Evening.

-How are you doing?

-Very well.

-Ellie. Nice to meet you.

-Jimmy.

-Hiya. Are you all right?

-Nice meeting you.

So, Jimmy, where are we off to on this really dark, cold night?

We're going to head out and do a thermal-image red deer count

just up the glen there, in a bit of woodland.

That's ideal. So, where are we all sitting?

-Yourself and Jamie will be in the back.

-OK.

Thank you.

Right.

So, what's all the kit that you use to do this?

We're using a hand-held thermal-imaging camera,

which is this device here.

It looks like massive binoculars.

It's effectively a giant pair of binoculars which picks up...

it detects differences in temperature,

so it picks up the heat signature of any living thing,

be it a mouse, a bird or a deer.

-Really? Down to a mouse?

-Absolutely.

-Wow!

And then whatever I'm seeing through the camera

is connected via a live video feed to the laptop here,

which will display effectively the live video

from what the camera's seeing onto the screen.

-So any deer that we see, you can see on the laptop.

-Fantastic!

-So you'll see exactly what I see through the camera.

-Excellent.

As we head out into the wild weather,

the temperature drops and the rain turns to snow.

But thankfully, it's not long before we come across our first group.

Oh, there's a deer! There's a deer already! Oh, there's a few!

How many have we got there? One, two, three, four, five.

How far away are they?

These ones are probably 150 metres.

-And there's one much closer.

-Oh, yeah!

Maybe 30 metres away.

Why do you do the counts in winter?

Obviously, during the winter, night-time temperatures are colder.

Because we're relying on a thermal-imaging camera,

it detects heat sources.

So the difference between an animal's body temperature

and the atmospheric temperature.

On a cold, frosty night, it's a much sharper, clearer picture.

That allows us to pick up deer much easier.

What this really shows is how little body heat they lose.

-It's just really around the...nose.

-They're pretty well insulated.

You can see their coats there and obviously their legs,

the eyes and the nose is kind of where the hotspots are.

And that's where the heat's going to be lost.

The rest of it is really dark.

You can see around their necks,

-they've got a quite, sort of shaggy mane.

-Yeah.

And that's quite typical of red deer stags.

Jimmy and Jamie go out on winter nights,

braving all conditions to count the deer populations.

And tonight, it seems they are everywhere.

Wow! There's loads! My goodness!

A big group of stags there.

It's pretty wild weather out there.

How do they seem to do in the winter?

Deer are pretty well equipped to deal with the Scottish climate.

They've been here for a long time, so they've seen it all before.

As humans, we think, "We wouldn't want to be out in this,"

but, you know, they've got, um...

particularly, they've got their winter coats,

obviously, at this time of year, it's thick.

The individual hair fibres are hollow,

so they capture air and they're insulated.

So...yeah, they'll obviously use woodland to their advantage

to shelter from the wind.

What they don't like is wet, driving rain.

That really can suck the energy out of them.

So they're pretty clever at finding somewhere sheltered

out of the wind, where they've got, um...

somewhere where they can feed and get a bit of respite from the weather.

In Scotland, red deer populations have doubled

from around 150,000 in the 1960s

to over 300,000 today.

And the data collected by Jamie is vital for many people.

Once you've got all this information,

what do you or what do landowners do with it?

Every landowner, land manager

will be doing something different with their land, with their deer.

Whether that's areas which have nature conservation interest,

such as, um...woodland regeneration.

So they'd be looking at keeping a balance between deer numbers

and allowing woodland to regenerate.

We might be counting deer

where they may present a risk to public safety, to road accidents.

We may be counting deer in an agricultural setting,

where they might be having an impact on agricultural crops.

So there's a whole range of things

that this information can be used to help provide advice for.

The camera picks up a whole host of woodland animals out in winter.

There an owl there! That is...fabulous!

-A tawny owl.

-Oh-ho-ho-ho!

He's sitting on a fencepost.

Oh, and off it goes!

Joy of a shot, that one.

Jimmy and Jamie spend up to ten hours a night

in freezing conditions counting these deer.

It may be hard and cold work,

but monitoring their numbers across Scotland is vital

to maintain the health of our forests.

Throughout our history, humans have always had to balance

the needs of the forest in different ways.

And in winter, this means tree felling.

This is the time of year when people harvested the forest for fuel

and building materials.

Local woodsman Peter Quelch is passionate about keeping up

this winter tradition known as coppicing.

-Hi, Peter.

-Hi.

Am I able to come in and take the glory

in the final few seconds of felling this tree?

-Well, you can't work these saws on your own.

-Oh, right, OK.

So it's all about pulling with these? I've used it once before.

There is a cut. We're going there.

-Ooh.

-No rush.

There we go.

Fantastic. You made very light work of that with an axe and a saw.

-They're very old-fashioned tools, aren't they?

-They are.

But they're the normal tools of woodmanship, as it were,

before forestry,

in the 19th century, which is when this work was going on.

How is coppicing done and why is it done in the winter?

Coppicing was a system of regularly cutting trees.

It's a sustainable system, it's a renewable system.

Because there's instant regrowth, as long as animals are kept out.

This ancient form of winter woodland management allows shoots

to regrow from felled tree stumps.

The trees aren't killed and continually grow back.

Over time, this creates characteristic, multi-trunked trees.

So, historically,

why was this sort of work done in the winter?

All broad leaves are felled in the winter when the sap is down,

when the leaves are off. The trees are dormant.

If you felled a tree like this in summer,

it would already be gushing with sap.

If the sap's down, the sugars are down, it's fairly dry inside,

therefore it seasons better

and everything you make is better from winter-cut broad leaves.

Also, it's easier to move on the ground, although it's wet.

In many countries, they do felling when the snow's on the ground

and horses can go over it, or you can use sledges easily, for example.

Whatever the weather, horses have traditionally been used

to clear the felled timber.

As recently as the 1950s, there were more than 400 horses

working in British forests, dragging millions of trees

to our busy sawmills.

As tractors took over, horse logging declined,

but it's still a method used today,

as Matt Baker discovered in the Lagan Valley Forest

in Northern Ireland.

'Steven Donaghy is one of Ireland's only horse loggers,

'reviving a tradition which had died out here.

'And it's not just for show -

'it's actually quicker than using a tractor.'

-Come on!

-I've got to leg it to keep up with him! What a good boy.

Go on, go on, go on.

-Up-up-up!

-Whoa.

And his brakes work perfectly.

That is... That was extraordinary. He doesn't hold back, does he?

No, that's it. Whenever he needs to pull, you see him,

he pushes into it and he just rips straight into the forest, like.

And you obviously love this?

It's far better working with a living animal than a machine.

We had the tractor on the start of the site there and it took about

half an hour to even get the tractor in there and it wrecked the ground.

It's all about watching the horse, the horse watching you, too.

You see him now, he's looking, his ears are turned round

-listening to me, waiting for me to give him the command.

-Yeah.

'Samson's an impressive horse,

'but how will he perform with me at the reins?'

Go easy with him. If he starts to get a bit fast, say, "Easy, easy,"

-pull on the reins and he'll slow down.

-All right.

-Let's have a go, Samson. Let's see what happens, my friend.

-Go on.

-Keep him right, that's it, yep.

-Good boy. Steady.

-That's it.

-Right, right.

-Go on, go on.

-Good boy.

Good lad.

Left, left!

-Left! Good lad. Up-up-up.

-That's it, run with him. That's it. Up!

Wey! Nearly went!

-Right, right, right.

-Go right.

Hup-hup-hup!

Good boy. Good lad.

Go on, hup!

Stay. Whoa. Park up. Beautifully done. Lovely.

I'll tell you what, this is some feeling.

Coppiced woodlands like Lagan Valley in Northern Ireland

and the Knapdale area here in Scotland

are harvested in rotations, so every winter, there are trees to fell.

I feel like I ought to do a little bit more work.

-Do we need to head on up there to do some chopping?

-Yeah.

I'll bring this. Here we go.

'Once on the ground, the trees are cut by hand, which is no mean feat.

'Every part of the tree is used.'

The top part there, the rough wood, can be useful

and the rest of the tree can be made into better things.

We could cut this every foot or so into clogs.

And it's not just clogs -

keeping up with old traditions, Peter uses 19th-century tools

to make a whole range of items.

From brooms, to timber joists for houses,

tent pegs and barrel hoops.

The wood from these trees would have had many uses, but perhaps

most importantly, at this time of year,

they'd have been turned into charcoal for winter fuel.

Charcoal burning was once an essential part of every woodsman's year

in the late autumn and early winter,

a tradition carried out in areas such as the New Forest in Hampshire.

You'd get a real good fire going, real good hot base.

And then the drum, we'll raise it up

roughly about four inches, with wooden blocks.

You pack it in the drum as tight as you can, really.

It's looking quite good at the moment.

It's building up a lot of heat inside the drum now, which is what we want.

You don't want the wood to really burn,

so you are more or less cooking it.

But once you know it's well alight at the bottom,

you can start shutting the air out.

Then you're just keeping the fire, it's just turning over then

and it's not roaring away.

That's when it really starts cooking and you get loads

and loads of white smoke come out.

Charcoal is formed when the heat from the fire drives off water

and impurities to leave just carbon.

The white smoke is the water being turned into steam.

When it starts to really turn to charcoal,

very thin smoke starts coming off then, bluey colour.

And that's when you can start really shutting it down.

You shut all your gaps up round the bottom, then you shut the top off.

Without the air getting to it, it'll just naturally go out.

Just let the drum cool down, then.

With a bit of luck, you'll have some nice charcoal.

Just enough to make a few pound here and there on a bag.

The charcoal from hazel coppices like this

was once the most valuable source of fuel in Britain.

It's almost pure carbon, burning hotter than coal,

and for thousands of years was the only fuel hot enough to smelt iron.

Now it is more commonly used for household fires -

as long as Dave can get it home safely.

Sometimes it has been known, you've just got to leave a little spark in there

and it can reignite again,

so the first few hours is crucial, or else you'll be driving home and say,

"What's that burning?" And your bag's alight in the back of the truck, you've got another fire!

Winter can be a tough time for both people and animals in forests,

but the trees themselves also have to cope with the conditions.

For them, it's all about preparation.

In autumn, deciduous trees like this one

draw down the nutrients from their leaves into their roots

and this helps them conserve energy during the cold, dark winter.

They survive the harsh conditions by shutting down

and staying dormant.

But there are species of tree in Britain, such as conifers,

which are able to remain active throughout the winter.

As Alan Titchmarsh revealed when he visited the conifer forests

in Scotland's Highlands.

This land can be covered in snow for up to 100 days of the year,

but the conical shape of many trees ensures the snow

slides off their branches, so they don't break.

The sap contains antifreeze,

so the water inside the tree doesn't turn into ice.

And of all the Caledonian trees,

the toughest must be the magnificent Scots Pine.

It's the world's most widespread conifer.

And there's one important adaptation that enables it

to grow in the most unexpected places.

The rock face below me is exposed to all the elements - wind, rain,

snow and nice.

But amazingly, some trees manage to grow even here.

Against all the odds, this pine tree here has managed

to establish itself on this sheer rock face.

There's hardly any soil here, and, consequently, hardly any moisture.

And what there is freezes in winter.

Temperatures here can fall to minus 20 degrees,

and winds can reach speeds of up to 140 miles an hour.

So, how does it survive?

By using these - pine needles.

They are leaves, but they're very, very narrow, and they're covered

in a waxy coating which hangs on to as much moisture as possible.

So, while deciduous trees shed their leaves in autumn

and grow new ones each spring,

the pine hangs onto its leaves all year round, saving itself the energy.

Remaining active during the winter means that these trees' pinecones

grow throughout the year.

And in the evergreen forests of Scotland's Cairngorms, this gives

rise to a sound you wouldn't expect to hear in the depths of winter.

CHEEPING

They're chicks - crossbill chicks.

It is unusual to find baby birds like this in winter, because chicks

need lots of food, and it's just not available at this time of year.

But pine cones allow crossbill chicks to get an early start.

The seeds are locked away inside the cones, and early in the season

when the cones are barely open, birds can't get at them.

Except the crossbill.

Which, likes its name suggests, has crossed bills.

It is the only bird in the world where the upper and lower parts

of its bill cross over when its bill is closed.

It's the perfect shape to prize open the wooded scales of the pine cone

and get at the seeds inside.

With the scales prized apart,

it uses its flexible tongue to pull out the seed.

By adopting this breaking and entering technique,

the crossbill opens a treasure chest of food,

allowing it to bring up its young at what seems to be

the worst time of year...

..and be one step ahead of all the other birds in the wood.

This family of Scottish crossbills have made a home for themselves

in what is left of the Caledonian forest...

..a mighty forest which once covered vast areas of Scotland.

Generations of human deforestation mean that only tiny fragments

of this ancient forest exist, and this is true throughout Britain.

Today, only 2% of our woodlands are ancient wood,

with the rest having being replanted and managed.

Large-scale forest management started with the creation

of the Forestry Commission, set up in the wake of the First World War.

By the end of the conflict,

over 90% of our wood was imported from abroad.

Worried by the prospect of the supply lines being cut,

the government ordered the creation of a strategic timber reserve -

trees that could provide pit props to keep our mines open.

That meant planting fast-growing species,

and the shape of our landscape was changed forever.

Today, the timber from these forests is harvested and precision cut

to be used in anything from paper products to houses.

In order to meet the huge demand for wood,

millions of trees are planted each year - a huge job.

'This is only carried out in winter, and for the forests around Argyll,

'it all begins here - on the edge of Knapdale Forest.

'Andy Hunt is the area operations manager

'from the Forestry Commission.'

-Andy, how are you doing? Nice to meet you.

-You too.

-Strange way for a forest to begin.

-Yeah, that's right.

-In here?

Yep, this is it, in here.

Wow, what's all this?

'He shows me a giant freezer, stacked from floor to ceiling

'with hundreds of thousands of saplings.'

So this is basically where we store our plants

when they come to us from the nurseries.

Why are they kept here in this cold room?

How cold is it in here, by the way?

Well, basically, we regulate the temperature to two degrees,

plus two degrees. That's just to maintain or ensure the trees

stay in a dormant condition.

Nice and peaceful, they don't start to develop in any way

-until we get them into the forest.

-How many have you got in here?

At the moment, we've got approximately 300,000 in here.

Through the planting season, we'll be planting about 3,500,000 trees.

Through this winter? 3,500,000?!

Basically between October and the end of March.

'The cold store here contains 15 different species of tree,

'dormant and ready to be planted.'

These are the trees we're going to be planting today.

This is Norway spruce. So we're taking these out to site.

-Can I have a look?

-Absolutely.

I can't promise you 3,500,000 today, but I'll do what I can.

-We'll do what we can.

-Oh, wow, little diddy things there.

So these are effectively dormant now,

and that means they'll sleep through the process of being planted.

That's right, until the spring, when the weather warms up.

They'll be in a new environment, the roots will establish,

and off they'll go.

Great, so they'll sleepwalk through this bit, then. Excellent.

-Shall we take this lot?

-Yep.

'In West Argyll alone, the 3,500,000 trees

'are planted each year in an area of over 7,000 acres,

'which is a massive job, especially considering it is still done

'the old-fashioned way - by hand.'

I've got my rubber gloves on now, I'm ready to give you a hand.

So just put one of these little ones in here, like this?

That's right, just make your slot deep enough and put all your roots

in nice and gently. Just heel them in. Nice and tight to the ground.

-Lovely stuff.

-That's it, then just give it a wee test,

-just to make sure it's...

-Nice and firm.

-Nice and firm, that's right.

It's manual labour, this, isn't it?

Are there not any machines that can do it?

We do have machines in development for planting trees,

but it's mainly on new planting sites

where we haven't had previous crops. This one we're in just now,

this has grown a timber crop previously,

and you can see some of the debris around that makes it

inaccessible for a lot of these machines.

So how many of these do you plant in a day?

Most planters will plant somewhere between 1,500-2,000 trees per day.

-A day?!

-It's quite hard work, and it's pretty intense.

I've hardly helped you out there, with one, have I?

We've got a bit to do. Let's move on.

A couple more in here.

So, Andy, once this is all planted, this area, what happens next?

How do you manage the site?

These trees will grow for the next 30, 40 years plus.

Through that time, we'll actually come in, when they get to

sort of 20 years old, 25 years old, we'll come in and thin this area.

That will open up the stems and allow light to come in.

'From 50 years old, the trees are ready to be harvested,

'cut down in their millions.

'It's an impressive spectacle - as amateur woodsman Rob Penn

'discovered when he visited Tywi Forest in Mid-Wales.'

This land belongs to the Forestry Commission,

Britain's largest woodland owner...

..looking after a third of all our woods.

Jerry Pritchard is the head of sales for Wales.

What we've got here is a clear felling operation of a spruce crop.

The crop, I would say, is 1950s. Reached maturity.

We've got a harvesting machine that will cut down approximately 100,

150 trees a day.

What?

Producing between 500 and 1,000 tonnes a week.

-Goodness me.

-In fact, this site he started yesterday.

So he's gone through here in a day...

He's gone through here in just over a day and a half.

We grow the timber, we crop it and we replant it.

It's a long-term operation, a long-term view.

But it's a harvest of a crop.

Each harvester machine weighs 20 tonnes.

A mechanical hand grips the trunk

while an automatic saw cuts the base.

When they are working fast, a machine can fell, strip

and log a tree every 30 seconds.

It's a very modern approach to managing woodland.

My personal best was 550 cubic metres in a day.

That was approximately 400 trees.

It is a good feeling.

The thing is, it gets harder and harder to break a personal best.

The figure keeps getting higher.

You've got to work harder to beat it.

The Forestry Commission's work may look brutal,

but it does more than just grow and harvest trees for timber -

it's also responsible

for managing many of the UK's forests to help wildlife.

'That includes the red squirrel.

'Once common, its numbers have decreased dramatically in Britain,

'largely due to the introduction of the grey squirrel from America.'

The Forestry Commission have just started to introduce these

red squirrel feeders to help them monitor their numbers here,

because Argyll is one of their last strongholds in the UK.

This camera trap monitoring trial is in its early stages,

but the results could be important -

Scotland is one of the red squirrel's last refuges,

with 75% of the UK's population.

In Invernes-shire, in the Highlands,

Michaela Strachan sat out to get a chance of seeing them up close.

I've got a red squirrel right in front of me.

My patience has paid off. They are such cute little characters.

One thing that really stands out are their little tufty ears.

At this time of the year,

those ears are as fluffy as they are ever going to get.

Not only do they look rather dashing, but they're very useful, too -

they use those tufty ears for communication.

By signalling with their ear tufts and tails,

they send important messages to other squirrels.

This is particularly important for their courtship

and to work out who is the most dominant squirrel in a territory.

Now, this morning, although it's cold up here, it's not freezing.

And so these little guys are quite active.

Once the temperatures really drop

and there is snow on the ground, they become a lot less active.

In fact, they do what a lot of people do.

They stay in bed.

Quite sensible, really!

Red squirrels have numerous nests, known as dreys,

which protect them from the harsh weather.

With up to seven centimetres of cosy lining,

these small homes can be up to 30 degrees warmer on the inside.

I've always loved squirrels.

To me, it doesn't matter whether I'm watching grey ones or red ones.

They're always very endearing and entertaining to watch,

and for me, that was a great way to spend an hour.

The forests in Knapdale extend all the way up through Argyll,

but the place I'm heading now isn't just any old piece of woodland,

but a hidden valley

with exotic flowering plants, even in the middle of winter!

Crarae woodland gardens was created 101 years ago

by Sir George Campbell - a man obsessed

with collecting rare plants from around the world.

Now, it spans 50 acres of forest -

exotic plants grow in the shelter of towering conifers.

Jason Copestick, the first gardener, has agreed to show me around.

-Hi, Jason, how you doing?

-Hello.

-Nice to meet you.

-Nice to meet you.

Even at this time of year, there are colours and scents,

such as Mahonia, and Hamamelis.

This is another strongly-scented plant. Have a little smell of that.

It's lovely.

'These exotic plants, many originally from the Himalayas

'and East Asia, find our British winters comparatively mild

'and burst into flower.'

Jason, how lovely to see this bloom in the middle of winter.

-What's this plant?

-This is a Mahonia, one called media charity.

This is one of Britain's most common garden plants, I suppose.

You see this everywhere. Heavily scented, beautiful plant.

The flowering plants - how do they manage to survive

-these really low temperatures?

-They have various means.

This plant we can see here obviously has leathery, waxy leaves.

This keeps them very well.

If they haven't got that, they tend to have different

mechanisms of keeping themselves warm.

What we see in this garden with a lot of plants is the rhododendrons,

they curl up to keep the heat in the leaves so they don't get too cold.

Obviously, another defence is losing their leaves so they've not got

that surface area to let the cold in, which is what deciduous plants do.

What about the flowers themselves, how do they survive the frost

-and snow?

-They survive frost and snow by being very small plants.

I don't know if you can see this sort of bell-shaped effect.

It keeps them warm. It means they don't burn,

because obviously plants in the winter, you will see this burning

effect where the edges go brown if the petals and leaves are too big.

You've got this very compact, small area, so the frost can't affect it.

It seems amazing that, in the middle of winter,

flowering plants can attract pollinators.

Generally speaking, that's because they have a very strong scent.

They may have insignificant flowers, but it's scent.

What do you tend to see in the winter, in terms of pollinating?

We tend to see birds, really.

They are the mainstay of pollination at this time of the year.

Yes, there will be the odd insect. There are some hardy insects about.

But obviously, with there not being the numbers,

you don't see them as much. But they are about.

These plants use a very strong scent to attract animals

from a great distance - far more so than in the summer.

What about generally in the winter,

what should people who've got gardens be doing about now?

At this time of year, especially on a frosty day, very little,

to be honest. Don't try and prune things,

because the cold will get into these open wounds.

It's more about keeping the wildlife happy

and keeping the place tidy, to be honest.

At the moment, we're not really doing

what you would call traditional gardening.

It's more about landscaping,

more about thinking about next year's work.

That sounds like an office job with a coffee,

-thinking about next year's work!

-I wish it was! I wish it was.

'This place might be a plant collector's paradise,

'but this garden also holds another secret.

'Hidden amongst the trees of this woodland garden

'is a forest testing site -

'an experiment started 80 years ago to find foreign trees that can

'survive our British climate.

'And it has resulted in an absolute giant.'

Wow, this is an epic tree.

This must be one of the biggest trees you have here, is it?

I would believe so, yes.

This is obviously a sequoia or, as we know it, a giant redwood.

This comes from the hills of California.

The hills being snowy - in fact,

covered in snow for the majority of the year.

So it can cope, then, with our very chilly winter?

Very much so. In fact, it's covered in its own little electric blanket.

-If you feel it, it's very soft.

-Yeah, it is, spongy, even.

-Try and give it a wee punch?

-Really?

-Really.

-Let's have a go.

Oh, that is soft! Gosh, that's amazingly soft. How thick is it?

It's about a foot thick.

Yes, they come from a very, very cold, wintry climate.

In California, the oldest trees can reach record heights

of over 370 feet.

In the UK, they are growing well, but as the experiment is

relatively recent, no one knows how big these trees will grow.

Giant sequoias can live for over 3,000 years,

so this one is an infant at just 80 years old.

They provide the perfect winter habitat for one of our winter birds.

But to see them, you have to wait until dark,

as Iolo Williams did in Newtown in Wales.

And this is it. It's a tree creeper.

The bird has dug himself a little hole into that soft bark,

knowing full well he is going to be insulated all-around.

His face, belly and feet have gone right in

and all that sticks out are his dense back feathers.

And he also knows that any passing owl is never going to see him.

Because those feathers blend in perfectly with the surrounding bark.

And that's one of the cosiest roosting sites that any bird

could possibly have.

It's not just the tree creepers that are worth seeing.

In winter, woodland plants put on a spectacular display.

There is one flower that really epitomizes the British winter,

and that's the snowdrop.

It's not native but it's spent the last 400 years

making its home in our woodlands.

Snowdrops were originally brought to the UK from the Mediterranean

and Eastern Europe, and these days, they are big business,

especially at the Cambo Estate in Fife.

There are few things as beautiful as a walk through the woods.

Particularly when they are sprinkled with snowdrops wherever you look.

Here though, they are not just decorative.

They are a real cash crop.

I like snowdrops, but some people absolutely love them

to the point of quite literal obsession.

Which makes some varieties worth their weight in gold.

-This one here is grumpy.

-Why is it called grumpy?

If you look inside, you can see his face.

-He looks pretty miserable, doesn't he?

-That's amazing!

That's so creative to come up with that.

I would see that a million times and never even see a face.

A lot of them have got these wonderful little faces inside.

He must be a really popular one.

-That's a great little surprise in there.

-Yes, he's a very popular one.

Also quite an expensive one.

-It's one of the rarities.

-So how expensive are we talking?

£30 or £40 a bulb.

-Per bulb?

-Per bulb. That's not a record, no.

I think the most expensive one so far has been £226.

-£226 for a single snowdrop bulb?

-Yes.

-That's incredible.

It does seem crazy, doesn't it?

This is Catherine Erskine's kingdom.

She's a galanthophile, that's a snowdrop enthusiast to you and me.

And in these 70 acres of woodland, she grows no less than 300 varieties.

Not just because she loves them, but because they are a good earner.

What's the thing that really draws you to snowdrops?

Because to me, they are beautiful, but they all look quite similar.

They're white, and a similar shape. Green bit on the end.

What's the huge draw for you?

I suppose what really started us off was snowdrop farming.

With the downturn of agriculture,

farming used to pay for almost everything on the estate.

And we needed more income, and we had this wonderful

resource of snowdrops, so we started farming the woods.

What we are standing in now looks ornamental,

and looks like something you just planted to look good,

but this is an active farm, believe it or not.

This is almost like a mini field. It's a snowdrop field

of a particularly strong form of the single snowdrop.

You'll see these ones, they are very tall.

Lovely strong leaves.

Nothing special in the marking so we are bulking them up here

and we will be able to sell them.

Why are they planted amongst trees

and in a really patchy naturalistic way? Is that just for the look?

Partly for the look, but also, they are happiest like this.

Snowdrops have resisted all my attempts to grow in straight lines.

I've tried growing them in crates so that I could find them dormant.

But no, they are much happiest in the wood.

Our woodlands can be surprisingly active in winter.

There really is life thriving, if you just know where to look,

as Sanjida O'Connell discovered

when she visited Hebden Bridge in West Yorkshire.

It's 7:00 in the morning, but listen to this.

BIRDS CHIRPING

This whole valley is already alive with birdsong.

February is a good time to get a handle on birdsong.

Because at this time of the year,

it's the native British birds that are shouting loudest.

What's even better is that there are no leaves on the trees

so it's much easier to match the birds to the birdsong.

Hardcastle Crags is a real hotspot for nature.

There are loads of birds here but there's another creature that

lives in these woods that outnumbers them by several million to one.

It would be really easy to mistake this pile of pine needles

and twigs for a bit of woodland debris.

But this is actually the nest of the northern hairy wood ant.

And look at it. It's massive! This one is almost as big as me.

And it's certainly a lot wider.

There are 400 nests at Hardcastle Crags.

With a total of 200 million individuals.

That's over three times the UK's human population

on just one hillside.

One person who knows the ants' life-cycle inside out is

National Trust warden Ian O'Leary.

-This is massive, isn't it? It so impressive.

-It's huge, isn't it?

A structure like this is the equivalent of human beings

building Everest by hand.

-Wow! That's amazing!

-It is.

And is this what you see is what you get,

or is there more to it than this?

There's more to it as you look round.

It goes another two metres at least down into the ground.

And there will be kilometres of tunnels

that are maintained by these ants.

So how many ants do you think are in here?

There would be over a million individuals in this particular nest.

All maintaining the thatching, which they are trying to repair now.

And keeping the tunnels clean, looking after the pupae

and the eggs.

Am I right in thinking that the million ants in here are all female?

They are. They are all sisters. The males have one purpose.

They come out in May with wings, fly and mate with the queen.

And then they die off and the rest is left to the female workers

to forage and look after the young.

-Ant girl power.

-Ant girl power, yes.

They are called northern hairy wood ants. What's the hairy bit?

-I know, because they don't look very hairy, do they?

-No.

Somewhere on here you've got, if you look for where the mandible

is here, just going up from there to, see the little eye?

-Yes.

-There is a little ridge of hairs.

-Are they quite defensive?

-They can be, yes.

Under any threat, they will definitely get rid of an intruder.

If you've got a tissue, I will be able to show you how they do that.

Yeah, I've got one in my pocket.

If we get the ants interested in this bit here,

get a few on there, you can see straight off...

They are heading for it straightaway.

What are the actually doing here?

That's actually spraying formic acid.

-So that's coming out of its abdomen here?

-On its lower abdomen, yeah.

You should be able to actually smell that.

It does. It smells quite pungent. It's a bit like fish and chips.

It's like the vinegar.

Ants' nests make it easy to spot in the forest, but here in Knapdale

there is another animal that leaves tell-tale signs of its activity.

The beaver.

Since 2009, four families of beavers have been reintroduced

back into this very forest.

For the first time in 400 years.

Heading up this reintroduction is

Simon Jones of the Scottish Beaver Trial.

-Simon, how are you doing?

-Nice to meet you, Ellie. How are you?

Two years ago, the BBC came here with specialist cameras to try

and film these elusive, nocturnal animals,

spending three weeks sitting in the dark, waiting.

HE YAWNS

And they got some incredible footage.

HE LAUGHS

I got it.

I found it straight away. It's right here.

'I've come back to see how they are getting on.'

There's lots of signs of activity here.

Yes, this is classic beaver tree felling activity.

Really, it's the only species we would find in the UK that could

produce something like that.

If you come across that anywhere in the UK,

it's definitely beaver activity.

It always surprises people that they do actually eat this wood,

-don't they? In the winter, particularly.

-Yes.

Beavers are completely vegetarian, they're herbivorous.

It's a common misconception that they eat fish. They don't.

They just eat vegetable matter.

In the winter, this time of year, what they really need to

rely on, heavily, is the bark of broadleaf species of trees.

It's actually not the wood itself that they are after.

You can see that they spit the hardwood out as they chew through it.

It's the vascular tissue,

the tissues within the tree that move the sap up and down

that's the part of the tree that they're really after,

as well as the bark.

They must have impressively strong teeth in order to fell a tree.

Exactly. Millions of years worth of evolution has really produced

something that's perfect to deal with wood.

If we have a look at a beaver skull, and I've got a replica with me here,

you can see really that the tools of the trade

are really these incisor teeth.

You see the front is this sort of bright orange colour,

and that's cos it's got a really hard enamel.

Behind it, at the back of the tooth, is this softer, whiter dentine.

And that erodes at a different rate from the hard enamel.

So by sharpening the teeth, by grinding the teeth together,

beavers are able to put on this chisel-like edge.

-Incredibly sharp edges.

-Exactly.

Does there tend to be more of this type of building

activity at this time, landscaping in the winter?

Yeah, well, the beavers spend a lot of time,

particularly in the late autumn and the early winter,

getting themselves ready to get through the harsh winter months.

Tree felling is part of that.

'All this winter preparation is the work of one beaver family.

'They have not only felled the trees here for food

'but also for construction.

'And further round this lake,

'is this family's most impressive accomplishment.

'A beaver dam.'

Oh, my goodness!

It must take a huge amount of energy to build these dams.

So why do they do it?

Well, beavers fundamentally need water to move around.

They're not very good on land

so they swim wherever they can rather than walk.

They also need to protect the entrance to the lodge.

They must have an underwater entrance to the lodge,

so therefore they need a certain depth of water.

So it's about protecting the lodge and also allowing them

to swim to places to forage.

This huge dam is two metres high and 15 metres long

and, incredibly, it was built by only two beavers.

It can be life saving.

Elsewhere in the world, like in North America,

where the water regularly freezes, dams like this

keep the lake deep enough so they can swim around underneath the ice.

'But their most important winter survival constructions

'are the beavers' home or lodge and food store.'

-It's a really big lodge, isn't it?

-Yep.

People are always surprised how big beaver lodges are.

This lodge is probably nearly ten metres long now.

If you include the big food cache that's been built

here in the autumn and over the winter.

By maybe five or six metres wide. Maybe 1.5 metres or two metres high.

So it's a structure that's as big an investment in time

and energy as a dam is for a beaver family.

They use the lodge to have offspring,

but would they also use it for protection from winter weather?

Yeah, it's the beavers' home and it is protection for everything.

So, at this time of year, coming into the actual mating season,

and then later in the spring, obviously, it's the breeding season.

But in the lead up to winter, critically, like the dams,

beaver lodges have a lot of work done to them.

So the beavers will be out in their territory.

They'll be felling lots of trees. Lots of them will be brought back.

The top finer parts of the trees will be converted into

their winter food cache.

And we can see the finer branchwood that sticks into the water there.

That's this huge investment.

This is this larder, this food cache that's designed to see

the animals through the winter period when weather is really harsh.

How much warmer is it in the burrows, in these chambers,

compared to outside temperature?

It can be up to ten degrees warmer than outside,

depending on the time of year.

What it is is quite a stable temperature.

'All this preparation allows beavers to survive,

'whatever conditions are thrown at them.'

In winter, beavers are able to stay safe and warm

in their insulated lodge,

opening up vents to let off steam and keep the temperature stable.

With a close by food-store, which can be accessed even under ice,

beavers can sit out the winter.

'But it's not just their lodges, it's also their bodies.

'And the best way to see that is to study the beaver up close.'

During the short winter days, the beavers will be in the lodge,

where it's several degrees warmer than out here.

But it's at night that they come out to find food.

'As the beaver project here is a trial, Simon and his team have

'to monitor the health of the beavers, especially in winter.'

And this means setting beaver friendly traps to try and catch one

to give it a check up.

It also might be my chance to glimpse one up close.

How do you set this, then, Simon?

-OK, if you go around to the other side.

-Yeah.

-I'll show you. You put the carrots on the top there.

-OK.

What we're going to do is take the catches, the latches at the end here,

lift them up and then you're going to slowly bring up their door.

It's quite heavy. Rest it on the top.

-Do we need to bait it?

-Yes. So we've got some carrots with us today.

That lures the beaver right into the middle of the trap.

So if the doors are sprung, then the animal is in the middle of the trap.

And there's no danger of the animal being caught...

-By these heavy doors.

-By these heavy doors.

If we now take the door and carefully move it down.

Have you ever caught anything other than a beaver in here?

We haven't caught any.

We've certainly had things that go into them.

Pine martens regularly go through them.

And we've seen birds hopping around them. And deer walk right past them.

Everything that you get in this forest.

But luckily, no, we've never caught anything else,

-aside from what they're designed to catch, which is beavers.

-Fantastic.

-Can we see it in action, then?

-Yes. Absolutely.

I'll show you how it works.

'With the trap set, it's time to test it.'

-Ah!

-And that's it.

It's really, really loud. It's quick but it's safe.

And the animal is now in there, it's got something to eat.

There's nice shelter in there. It's dark in there.

So the animals tend to just generally curl up for

a little while in there, until we come and check in the morning.

-So let's reset it, then, ready for tonight.

-Yep.

All set and ready for tonight.

Hopefully tomorrow,

I will get my first glimpse of a truly wild beaver.

At first light, I head back to the trap with Simon

and his team to check the trap.

The trap has been sprung, and sure enough,

there is a beaver inside.

This is a wild animal and it is vital that the team

work quickly and quietly to get the data

without causing any unnecessary stress to the beaver.

(So this is an annual event for each beaver?)

Yeah, we try and trap every animal every year and then, over time,

we can start to build up a picture of their body condition,

and how that changes through the five-year period of the trial.

So what Roisin and Rob are doing here now is,

we start by taking tail measurements.

And tail measurements are particularly important.

Tails are a bit like the health indicator of beavers.

So by measuring the length, the width and the thickness, you can

calculate the body condition and how much fat has been stored in the tail.

And in the winter, that's a particularly important thing.

And after, when they've finished doing the tail measurement,

they'll also maybe take a sample, maybe a faecal sample,

sometimes we take blood samples as well.

And that gives us more information that can go for analysis

back at the lab to tell us what a beaver's eating,

what its hormone levels are like,

and what its general health condition is as well.

And then the final step in the process is, when that's been done,

we will generally weigh the animal before the release.

'The check up is complete and this beaver is fit and healthy enough

'to be released back into the water.'

-Trap him for a bit.

-OK.

That's my first up-close encounter with a wild beaver.

It was amazing to be as close.

The tail was really quite thick at the base,

just showing how well it is, and how ready it is for winter.

And now to see it disappear off into the wild is a joy.

Subtitles by Red Bee Media Ltd