Would you like to inspect the original subtitles? These are the user uploaded subtitles that are being translated:
1
00:00:05,527 --> 00:00:09,440
Ten million species live on planet Earth-
2
00:00:11,127 --> 00:00:12,845
Each one is remarkable-
3
00:00:14,767 --> 00:00:16,598
But none can survive on its own-
4
00:00:21,207 --> 00:00:23,516
All life depends upon connections.
5
00:00:25,687 --> 00:00:28,679
Unexpected, invariably complex,
6
00:00:28,727 --> 00:00:32,845
beautiful relationships between
millions of plants and animals.
7
00:00:38,127 --> 00:00:40,721
This time, in our seasonal forests,
8
00:00:40,767 --> 00:00:44,760
why does this lynx need a caterpillar?
9
00:00:44,807 --> 00:00:49,164
Why does the tree need the fish?
10
00:00:49,207 --> 00:00:52,756
And why does this truffle fungus
need one of these?
11
00:00:53,727 --> 00:00:55,479
Flying squirrel!
12
00:00:58,047 --> 00:01:03,599
Connections like these
form the planet's great ecosystems-
13
00:01:03,647 --> 00:01:07,606
They're vital for all life-
14
00:01:07,647 --> 00:01:12,402
I want to show you our world
as you've never seen it before.
15
00:01:53,247 --> 00:01:54,885
New England in autumn.
16
00:01:56,287 --> 00:02:01,315
There really can't be a more magical place
anywhere on Earth
17
00:02:01,367 --> 00:02:06,725
to appreciate that dramatic transition
between summer and winter.
18
00:02:10,287 --> 00:02:13,643
But we mustn't get blinded
by this natural fiesta,
19
00:02:13,687 --> 00:02:19,683
because such an extreme transformation
is a huge challenge for life,
20
00:02:19,727 --> 00:02:24,357
and autumn is just one of many
transformations the forest must face-
21
00:02:28,727 --> 00:02:34,404
From summer to winter, this land of plenty
will appear to collapse,
22
00:02:34,447 --> 00:02:39,362
before attempting to rebuild itself
all over again in the spring-
23
00:02:52,647 --> 00:02:55,366
To see how, 1'm going to what is, for me,
24
00:02:55,407 --> 00:02:58,922
the greatest seasonal forest
on the planet-
25
00:03:06,847 --> 00:03:11,159
The wooded wilderness that stretches
right across North America-
26
00:03:13,527 --> 00:03:15,677
From the land of the Canadian lynx
27
00:03:15,727 --> 00:03:18,366
to the land of the grizzly bear-
28
00:03:25,207 --> 00:03:27,721
Our story begins in autumn-
29
00:03:38,807 --> 00:03:43,517
As the days are drawing shorter,
less light is feeding the forests-
30
00:03:47,767 --> 00:03:51,077
Deciduous trees are shedding their leaves-
31
00:03:54,487 --> 00:03:59,277
Many creatures are burrowing away
to escape the cold-
32
00:03:59,327 --> 00:04:03,206
And others are simply leaving-
33
00:04:05,047 --> 00:04:09,723
But there's one animal
with a crucial job to do,
34
00:04:09,767 --> 00:04:11,837
now, before the winter sets in-
35
00:04:13,967 --> 00:04:17,562
1t's a job the entire forest depends upon-
36
00:04:20,487 --> 00:04:24,878
The best time to see them is in
the first couple of hours after dark.
37
00:04:24,927 --> 00:04:27,760
And what I'm hoping is
that if I stand here
38
00:04:27,807 --> 00:04:31,083
and stay really quiet,
I'll be in for a real treat.
39
00:04:34,967 --> 00:04:41,440
1t's a creature 1've waited all my life
to see, but they move so fast!
40
00:04:49,327 --> 00:04:51,124
0h! Did you see that?!
41
00:04:52,847 --> 00:04:54,803
That was amazing,
it went right past my face!
42
00:04:55,967 --> 00:04:58,527
Flying squirrel!
43
00:05:03,687 --> 00:05:08,602
They really are expert gliders-
They can glide for up to 2OO metres!
44
00:05:14,087 --> 00:05:17,557
When I was a kid, I was obsessed
with things that were, you know,
45
00:05:17,607 --> 00:05:19,040
not meant to fly.
46
00:05:19,087 --> 00:05:23,000
Flying fish, flying frogs,
flying lizards, flying squirrels.
47
00:05:23,047 --> 00:05:25,242
And this is the first time
I've ever seen them.
48
00:05:25,287 --> 00:05:28,484
It was worth a 45-year wait - honestly!
49
00:05:33,767 --> 00:05:36,361
Did you...? 0h! Did you see that?!
50
00:05:36,407 --> 00:05:41,686
I felt it, it went right through my hair!
Seriously! Centre parting!
51
00:05:41,727 --> 00:05:44,036
It was like having a sheet of A4
coming right over my face,
52
00:05:44,087 --> 00:05:46,999
and as soon as they hit the tree,
they're running and up they go.
53
00:05:51,367 --> 00:05:54,837
They're just crisscrossing
all of the trees.
54
00:05:54,887 --> 00:05:59,165
And they immediately scamper up to the
top and then take off and glide again,
55
00:05:59,207 --> 00:06:02,882
and sometimes, I've noticed, they can
even change direction during flight.
56
00:06:11,647 --> 00:06:15,640
Urgh! 0ne hit me in the chest!
57
00:06:15,687 --> 00:06:18,201
It doesn't come better than that, does it?
58
00:06:18,247 --> 00:06:20,238
It doesn't get more exciting.
59
00:06:20,287 --> 00:06:24,724
But what on Earth
have they got to do with our story?
60
00:06:24,767 --> 00:06:27,725
Well, at the moment,
these flying squirrels are out and about
61
00:06:27,767 --> 00:06:30,440
in the woods trying to find
as much food as possible
62
00:06:30,487 --> 00:06:33,365
before the weather turns nasty
and the winter kicks in.
63
00:06:33,407 --> 00:06:38,640
But what are they after?
Well, they're after these - truffles.
64
00:06:39,687 --> 00:06:42,440
They're the fruiting bodies of fungi
65
00:06:42,487 --> 00:06:45,559
and they appear in the damp cool
of autumn-
66
00:06:47,967 --> 00:06:49,605
1n preparation for winter,
67
00:06:49,647 --> 00:06:54,516
the hungry squirrel needs to hoard food
such as truffles-
68
00:06:54,567 --> 00:06:58,116
But the truffles also need
the squirrel to eat them-
69
00:07:06,247 --> 00:07:10,365
As the squirrel moves through the forest,
the spores are dispersed-
70
00:07:14,727 --> 00:07:16,604
And that's crucial-
71
00:07:16,647 --> 00:07:19,764
Not just for the truffle,
but for the trees-
72
00:07:26,327 --> 00:07:29,524
What's so special about these truffles?
73
00:07:29,567 --> 00:07:31,683
They certainly don't look much,
74
00:07:31,727 --> 00:07:35,037
and the smell can be said to be
an acquired taste.
75
00:07:35,087 --> 00:07:38,284
And they're not just here
as another organism to be eaten
76
00:07:38,327 --> 00:07:40,841
by hordes of hungry squirrels either.
77
00:07:40,887 --> 00:07:42,764
Because without these truffles
78
00:07:42,807 --> 00:07:45,526
and all of the other fungi
here in the wood,
79
00:07:45,567 --> 00:07:50,482
this woodland simply couldn't function.
It couldn't exist.
80
00:07:50,527 --> 00:07:51,880
Why?
81
00:07:51,927 --> 00:07:54,441
Well, take a look beneath the soil
down here.
82
00:08:01,087 --> 00:08:04,443
Each truffle has thread-like roots
extending from it-
83
00:08:05,487 --> 00:08:10,242
The threads extract nutrients in the soil
from rotting material, like the leaves-
84
00:08:20,887 --> 00:08:22,684
And, cunningly,
85
00:08:22,727 --> 00:08:27,323
they also tap into the roots of the trees
to siphon off sugars-
86
00:08:29,087 --> 00:08:32,966
But this is not a one-way relationship,
because the tree
87
00:08:33,007 --> 00:08:37,080
can now tap into the nutrients
extracted by the fungal threads-
88
00:08:44,087 --> 00:08:48,080
This symbiotic relationship
between the trees and the fungus,
89
00:08:48,127 --> 00:08:52,962
where each is dependent on the other,
clearly helps the tree grow,
90
00:08:53,007 --> 00:08:57,398
but it's not only that.
It greatly extends the reach of its roots.
91
00:08:57,447 --> 00:09:02,123
Because in effect, they become
as extensive as the fungal network
92
00:09:02,167 --> 00:09:03,839
that they're connected to.
93
00:09:06,127 --> 00:09:10,439
1n autumn, throughout the northern
hemisphere, trees use fungi
94
00:09:10,487 --> 00:09:14,765
to extend their roots
and absorb sufficient nutrients
95
00:09:14,807 --> 00:09:16,001
for the big freeze ahead-
96
00:09:24,087 --> 00:09:26,726
1 love this little web of relationships-
97
00:09:26,767 --> 00:09:28,917
The squirrels, the fungi, the trees-
98
00:09:28,967 --> 00:09:33,040
1t ensures that they're all ready
to face the winter-
99
00:09:43,167 --> 00:09:47,524
But for me, one of the most
magical relationships of all
100
00:09:47,567 --> 00:09:50,923
is seen on the far west coast of Canada,
101
00:09:50,967 --> 00:09:56,963
as one of the world's most ancient forests
prepares for the oncoming challenge-
102
00:10:08,327 --> 00:10:13,401
Here, 1 can stand at the foot
of thousand-year-old cedars
103
00:10:13,447 --> 00:10:16,803
and 9O-metre tall sitka spruce trees-
104
00:10:24,687 --> 00:10:28,600
The combination of large mountains
and ocean winds
105
00:10:28,647 --> 00:10:31,878
generates unusually heavy rainfall,
106
00:10:31,927 --> 00:10:35,602
earning this place the title
the Raincoast-
107
00:11:08,687 --> 00:11:12,726
There's so much rain in autumn
that the rivers are swollen-
108
00:11:18,287 --> 00:11:21,677
And that is vital
to the forest's survival-
109
00:11:30,767 --> 00:11:34,123
There's a significant event happening here
110
00:11:34,167 --> 00:11:38,718
which allows the whole forest
not only to survive the winter,
111
00:11:38,767 --> 00:11:42,077
but also to flourish throughout
the course of the year.
112
00:11:42,127 --> 00:11:44,436
But, you know,
the really incredible thing is
113
00:11:44,487 --> 00:11:48,765
that this key to life is not here
in the forest at all at the moment,
114
00:11:48,807 --> 00:11:51,002
but it will be soon.
115
00:12:01,687 --> 00:12:04,884
After years at sea,
salmon are returning to spawn
116
00:12:04,927 --> 00:12:07,964
in the same forest streams
in which they were hatched-
117
00:12:13,127 --> 00:12:15,880
And the swollen rivers
make it easy for them
118
00:12:15,927 --> 00:12:19,044
to swim deep into the forest-
119
00:12:22,327 --> 00:12:26,764
But the scent of home also draws them
irresistibly towards danger-
120
00:12:29,647 --> 00:12:33,037
Predators make the most
of this banquet of seafood-
121
00:12:47,567 --> 00:12:52,038
But none of them compare
to the most formidable fish-eater of all-
122
00:12:58,207 --> 00:12:59,925
Grizzly bears!
123
00:13:01,247 --> 00:13:02,362
Just look at this.
124
00:13:02,407 --> 00:13:07,765
There's a female here,
about 40 metres in front of me,
125
00:13:07,807 --> 00:13:10,924
in the shallows fishing for salmon.
126
00:13:11,967 --> 00:13:15,084
Behind her, on the bar over there,
she's got three cubs.
127
00:13:16,487 --> 00:13:18,443
They're not struggling
to catch the fish here,
128
00:13:18,487 --> 00:13:22,241
there's such a tremendous surfeit
of tired salmon out there.
129
00:13:22,287 --> 00:13:24,596
All she really has to do
is wander into those shallows
130
00:13:24,647 --> 00:13:26,239
until one comes close.
131
00:13:26,287 --> 00:13:29,404
And then she can grab it,
much to the delight of her cubs.
132
00:13:33,047 --> 00:13:36,926
For these cubs, it's the first salmon run-
133
00:13:36,967 --> 00:13:40,198
They've got to learn how to catch fish
by watching their mother-
134
00:13:44,887 --> 00:13:46,161
Look at this, look!
135
00:13:49,287 --> 00:13:54,156
This is the adult grizzly
that's just leapt off of the island there,
136
00:13:54,207 --> 00:13:56,596
and caught a salmon, look at that,
right in its mouth.
137
00:13:57,927 --> 00:14:00,202
Overjust six weeks in autumn,
138
00:14:00,247 --> 00:14:03,762
tens of millions of salmon
are going to return to these rivers-
139
00:14:03,807 --> 00:14:07,243
And during the course of a day,
one adult bear like this can eat
140
00:14:07,287 --> 00:14:12,725
40kg of salmon, and during the course
of the salmon run, 1,400kg.
141
00:14:12,767 --> 00:14:15,918
That's just one bear's intake.
142
00:14:18,527 --> 00:14:23,476
But every salmon caught by these bears
increases their chances of survival-
143
00:14:47,447 --> 00:14:49,836
And they are incredibly important
to these bears,
144
00:14:49,887 --> 00:14:51,718
particularly at this time of year
145
00:14:51,767 --> 00:14:54,839
when it's essential they bulk up
as quickly as possible
146
00:14:54,887 --> 00:14:58,402
before they slip into hibernation
with the winter coming.
147
00:15:01,247 --> 00:15:03,807
This cub hasn't quite
got the hang of it yet-
148
00:15:04,887 --> 00:15:09,961
But he hasn't got long- The salmon run
has only got a couple of weeks to go-
149
00:15:13,647 --> 00:15:16,684
Until they learn,
Mum has to work even harder-
150
00:15:22,967 --> 00:15:26,357
Every salmon caught
makes a real difference-
151
00:15:36,967 --> 00:15:40,198
These bears, those that are close
to a huge amount of salmon,
152
00:15:40,247 --> 00:15:43,637
grow 80%/ larger than those in other areas.
153
00:15:43,687 --> 00:15:46,247
They have 25%/ more cubs
154
00:15:46,287 --> 00:15:49,006
and occur at densities 50 times greater.
155
00:15:49,047 --> 00:15:52,483
So salmon, frankly,
are great news for bears.
156
00:16:12,927 --> 00:16:14,724
Exciting as it is to watch,
157
00:16:14,767 --> 00:16:19,966
there's a lot more going on here
than simply bears catching fish-
158
00:16:21,247 --> 00:16:24,523
And the reason
is thanks to what happens next-
159
00:16:32,567 --> 00:16:36,606
And the only way to see it
is with remote cameras
160
00:16:36,647 --> 00:16:38,444
positioned deep in the forest-
161
00:16:53,007 --> 00:16:56,602
These younger bears have carried fish
3O metres from the river-
162
00:16:59,487 --> 00:17:04,197
Because here they're less likely
to be challenged by hungry adults-
163
00:17:05,607 --> 00:17:07,245
So they can eat in peace-
164
00:17:10,807 --> 00:17:14,482
There's so much fish available,
they just eat the richest bits
165
00:17:14,527 --> 00:17:17,405
to lay down enough fat for hibernation-
166
00:17:19,407 --> 00:17:23,764
The rest appears to be wasted,
abandoned on the forest floor-
167
00:17:26,207 --> 00:17:28,038
Along with our camera-
168
00:17:34,127 --> 00:17:37,517
The aftermath of this feast
is unbelievable-
169
00:17:39,407 --> 00:17:44,765
Up to four tonnes of carcasses are left
in an area the size of a football pitch-
170
00:17:46,847 --> 00:17:52,001
But what have dead fish got to do
with the forest preparing for winter?
171
00:17:55,207 --> 00:17:57,721
Well, this is where it starts
to get really intriguing,
172
00:17:57,767 --> 00:18:01,840
because the catching of the salmon
is just the start of it.
173
00:18:01,887 --> 00:18:06,119
Bears aren't the only creatures
attracted by such a feast-
174
00:18:08,327 --> 00:18:14,118
A banana slug- At 25cm long, it's one
of the largest slugs in the world-
175
00:18:17,727 --> 00:18:20,002
And masses of insects-
176
00:18:26,247 --> 00:18:29,045
These flies won't survive the winter,
177
00:18:29,087 --> 00:18:32,238
but if they plant their eggs
in the salmon's flesh,
178
00:18:32,287 --> 00:18:34,005
their offspring might-
179
00:18:39,927 --> 00:18:45,479
This flurry of activity eventually breaks
the flesh down into simple nutrients
180
00:18:45,527 --> 00:18:47,836
that are absorbed into the soil-
181
00:18:56,687 --> 00:19:00,236
The significance
of all of this decaying fish
182
00:19:00,287 --> 00:19:04,326
goes far beyond it being
just a feast for scavengers.
183
00:19:04,367 --> 00:19:09,043
Without all of these rotting salmon
accumulating here every autumn,
184
00:19:09,087 --> 00:19:11,920
this forest would be
a very different place.
185
00:19:14,127 --> 00:19:18,882
The salmon nutrients in the soil
are taken up by the fungi-
186
00:19:23,167 --> 00:19:28,958
So this ancient forest is better equipped
to face the almighty change
187
00:19:29,007 --> 00:19:30,759
that's fast approaching-
188
00:19:43,847 --> 00:19:47,920
For forests in the northern hemisphere,
time has run out-
189
00:19:53,047 --> 00:19:57,677
Every day, the sun sinks lower in the sky-
190
00:20:29,127 --> 00:20:31,038
Winter.
191
00:20:31,087 --> 00:20:33,203
And on the face of it,
all of the life here
192
00:20:33,247 --> 00:20:35,886
seems to have just gone away.
193
00:20:36,967 --> 00:20:38,923
Those truffles and the seeds,
194
00:20:38,967 --> 00:20:42,164
they're locked away
underneath all of this snow.
195
00:20:42,207 --> 00:20:44,118
The salmon run is over.
196
00:20:44,167 --> 00:20:48,479
The vegetation - look at it -
it appears just to have shut down.
197
00:20:48,527 --> 00:20:52,998
Even the water is in short supply.
It's all frozen.
198
00:20:54,207 --> 00:20:57,404
All of those connections
appear to be broken.
199
00:21:00,847 --> 00:21:04,396
The fungi have reduced their recycling
to a bare minimum-
200
00:21:06,087 --> 00:21:10,603
And the trees they're connected to
are producing little in return-
201
00:21:15,207 --> 00:21:19,439
The deciduous trees pre-empted
the winter by shedding their leaves-
202
00:21:19,487 --> 00:21:23,082
The conifers are slowing down too-
203
00:21:23,127 --> 00:21:27,325
The waxy coating on the needles
protects their leaves from the cold-
204
00:21:33,487 --> 00:21:38,117
But not everything here can exist
in a state of suspended animation.
205
00:21:38,167 --> 00:21:41,284
Some of the animals
have to remain active,
206
00:21:41,327 --> 00:21:44,876
and surviving in conditions like this
isn't easy.
207
00:21:55,807 --> 00:22:00,756
The icy cold is the cue for the bears
to leave the forest altogether-
208
00:22:03,607 --> 00:22:05,279
With the salmon run over,
209
00:22:05,327 --> 00:22:09,286
they are retreating to their winter dens
up in the mountains-
210
00:22:10,407 --> 00:22:14,605
They must spend the entire winter
living off their fat reserves
211
00:22:14,647 --> 00:22:17,366
gained by feeding on all of those salmon-
212
00:22:20,647 --> 00:22:24,560
The squirrels and other small mammals
must keep their activity to a minimum---
213
00:22:27,927 --> 00:22:31,317
---only occasionally venturing out
to retrieve their autumn caches-
214
00:22:39,167 --> 00:22:43,399
The lower the temperature falls,
the more vulnerable creatures become-
215
00:22:45,927 --> 00:22:50,159
Winter has been too brutal
for this young white-tailed deer,
216
00:22:50,207 --> 00:22:54,564
but at least it's an opportunity
for some nocturnal scavengers-
217
00:22:58,367 --> 00:22:59,482
A racoon-
218
00:23:01,487 --> 00:23:06,322
Out of the forest, a fisher,
a relative of martens and weasels-
219
00:23:06,367 --> 00:23:10,155
And it's smart enough
to keep this meal to itself!
220
00:23:24,967 --> 00:23:30,166
But there is more to this lifeless-looking
forest than just the scavengers-
221
00:23:37,807 --> 00:23:43,882
For most creatures,
winter is a brutal and unforgiving time.
222
00:23:46,007 --> 00:23:50,842
But others actually thrive
in these conditions.
223
00:23:50,887 --> 00:23:55,915
You see, for animals
that have adapted to live in winter,
224
00:23:55,967 --> 00:24:02,725
this stripped-down forest ecosystem -
well, it's a wonderland.
225
00:24:21,967 --> 00:24:25,926
1n winter here,
there are beautiful connections
226
00:24:25,967 --> 00:24:29,880
between some of the forest's
most enchanting characters-
227
00:24:37,967 --> 00:24:42,563
There is one predator here,
an incredibly important animal
228
00:24:42,607 --> 00:24:45,599
that has no intention
of avoiding the snow,
229
00:24:45,647 --> 00:24:49,560
because, unlike me,
it's perfectly adapted to it.
230
00:24:49,607 --> 00:24:53,486
But it's an enigma,
a really, really shy animal,
231
00:24:53,527 --> 00:24:55,757
one that's difficult to study.
232
00:24:55,807 --> 00:24:58,560
Having said that,
scientists have been tracking them
233
00:24:58,607 --> 00:25:01,724
through the forest here
for more than a decade.
234
00:25:12,407 --> 00:25:16,082
Researchers from the Maine Department
of Fisheries and Wildlife
235
00:25:16,127 --> 00:25:19,642
have set a trap to catch one alive-
236
00:25:32,167 --> 00:25:37,002
With those distinctly pointed ears,
it can only be a Canadian lynx-
237
00:25:39,527 --> 00:25:43,122
Lynx are the world's
most northerly dwelling cats-
238
00:25:48,727 --> 00:25:54,040
And this particular lynx is well known
to chief scientist Jen Vashon-
239
00:25:56,127 --> 00:25:58,766
The ear tags are blue with white.
240
00:25:59,967 --> 00:26:02,606
- That indicates it's L1 -1 1 .
- (LYNX BARKS)
241
00:26:02,647 --> 00:26:08,005
He's called L 1-1 1
and was born in May 2OO4-
242
00:26:17,447 --> 00:26:20,962
They've discovered that he is just one
of hundreds of lynx living here-
243
00:26:25,647 --> 00:26:28,559
JEN: It's too intimidated
with everybody right there.
244
00:26:44,127 --> 00:26:48,006
1n fact, there are more lynx
living in these eastern forests
245
00:26:48,047 --> 00:26:50,481
than anywhere else in North America-
246
00:27:10,007 --> 00:27:16,765
Now, the fact that L1 -1 1 has lived
all of his life in this frozen forest
247
00:27:16,807 --> 00:27:21,722
has to mean that this is
a perfect place for a lynx to live.
248
00:27:21,767 --> 00:27:27,080
But how can a top predator
like this survive
249
00:27:27,127 --> 00:27:29,277
in such a stripped-down environment
250
00:27:29,327 --> 00:27:32,763
when there appears to be
so little else here?
251
00:27:45,847 --> 00:27:48,725
The tracks of their prey are everywhere,
252
00:27:48,767 --> 00:27:52,476
but actually finding one
is a real challenge,
253
00:27:52,527 --> 00:27:55,883
because its winter camouflage is perfect-
254
00:28:16,767 --> 00:28:22,763
It's taken some finding,
but it's there - the snowshoe hare.
255
00:28:22,807 --> 00:28:26,482
You can just make out
its beady little black eye
256
00:28:26,527 --> 00:28:29,121
and the black tips to its ears.
257
00:28:29,167 --> 00:28:34,446
And these things form 80%/
of the lynx's diet,
258
00:28:34,487 --> 00:28:38,526
but as you can see,
they don't make it easy for that lynx.
259
00:28:38,567 --> 00:28:41,843
Their camouflage is astonishing.
260
00:28:41,887 --> 00:28:44,037
In the summertime, they're brown,
261
00:28:44,087 --> 00:28:46,840
but in the winter,
they moult through to a white coat.
262
00:28:46,887 --> 00:28:50,323
But they also use this thick brush.
263
00:28:50,367 --> 00:28:54,121
It provides them with excellent cover
to hide from the lynx,
264
00:28:54,167 --> 00:28:55,725
also hide from the elements,
265
00:28:55,767 --> 00:28:59,203
but it's also crucial
in keeping them alive,
266
00:28:59,247 --> 00:29:05,436
because they climb on top of the snow and
nibble at all of the shoots and the bark
267
00:29:05,487 --> 00:29:07,398
growing from all of this brush.
268
00:29:13,047 --> 00:29:15,766
Look at that - beautiful!
269
00:29:15,807 --> 00:29:18,116
And with those big snowshoe feet,
270
00:29:18,167 --> 00:29:21,318
it just sort of floats across
the surface of the snow.
271
00:29:32,647 --> 00:29:36,481
What the snowshoe hare needs most
to survive the winter
272
00:29:36,527 --> 00:29:38,882
is a specific type of vegetation-
273
00:29:41,367 --> 00:29:43,437
1t must be the right height to eat
274
00:29:43,487 --> 00:29:48,038
and provide enough cover
to hide from all of those lynx-
275
00:29:50,007 --> 00:29:53,477
So the vegetation here must be perfect-
276
00:30:00,767 --> 00:30:05,238
And the reason that it does grow into
this perfect environment -
277
00:30:05,287 --> 00:30:07,357
well, you could never guess-
278
00:30:11,847 --> 00:30:18,286
The most beautiful thing about this story
is that the lynx, the hare,
279
00:30:18,327 --> 00:30:21,160
patches of cover like this
amongst the forest
280
00:30:21,207 --> 00:30:23,801
didn't happen by chance.
281
00:30:23,847 --> 00:30:28,363
They're all controlled
by the most unlikely of creatures,
282
00:30:28,407 --> 00:30:33,481
a tiny thing, less than the size
of one of my fingernails.
283
00:30:33,527 --> 00:30:35,597
And at the moment, it's hiding,
284
00:30:35,647 --> 00:30:39,083
having burrowed into the bark
of one of these trees,
285
00:30:39,127 --> 00:30:43,803
or perhaps in a crack in a log
lying on the forest floor,
286
00:30:43,847 --> 00:30:46,042
covered with frozen snow.
287
00:30:46,087 --> 00:30:49,397
But it's there and it's waiting.
288
00:30:49,447 --> 00:30:52,120
It's waiting for springtime.
289
00:31:13,607 --> 00:31:17,395
As the hours of daylight increase
and the ground thaws,
290
00:31:17,447 --> 00:31:22,202
as if by magic,
the northern forests change again-
291
00:31:45,447 --> 00:31:49,963
As new leaves appear,
trees start producing sugars,
292
00:31:50,007 --> 00:31:53,044
and that's good for fungus in the soil-
293
00:31:53,087 --> 00:31:58,207
Entwined with the trees'roots,
they can siphon off some of these sugars-
294
00:32:00,407 --> 00:32:03,479
But not everything appears
so harmonious-
295
00:32:03,527 --> 00:32:07,645
1n the land of the lynx, something
extraordinary is happening to the forest-
296
00:32:10,567 --> 00:32:13,559
These trees may have endured the winter,
297
00:32:13,607 --> 00:32:16,804
but now it's spring, they're under attack-
298
00:32:19,007 --> 00:32:20,759
Some are even dying-
299
00:32:23,887 --> 00:32:27,197
But what's happening here now is vital
300
00:32:27,247 --> 00:32:31,320
for how this ecosystem functions
over the year-
301
00:32:34,087 --> 00:32:37,796
This defoliation is entirely natural.
302
00:32:37,847 --> 00:32:40,645
And I might be able to find
one of the culprits down here,
303
00:32:40,687 --> 00:32:42,405
although they're quite tricky to spot.
304
00:32:44,247 --> 00:32:47,603
They live in these fresh, green shoots.
305
00:32:48,807 --> 00:32:50,160
Yes, here we are.
306
00:32:50,207 --> 00:32:55,281
Now, wrapped delicately in these leaves
307
00:32:55,327 --> 00:32:58,444
is a species that is single-handedly
308
00:32:58,487 --> 00:33:03,163
influencing the ecology
of this entire forest.
309
00:33:03,207 --> 00:33:07,405
Inside this nest is the caterpillar
of the spruce moth - the budworm.
310
00:33:07,447 --> 00:33:10,917
And it hasn't only wrapped itself up
in those leaves
311
00:33:10,967 --> 00:33:14,437
to hide from predators,
because it's eating them as well.
312
00:33:14,487 --> 00:33:16,284
And it doesn't just eat the leaves.
313
00:33:16,327 --> 00:33:22,766
It also eats the buds, the flowers
and the cones on the tree here.
314
00:33:25,127 --> 00:33:28,164
Up in the canopy,
a tiny budworm caterpillar
315
00:33:28,207 --> 00:33:31,279
has just emerged from hibernation
316
00:33:31,327 --> 00:33:33,204
and it's racing to fatten itself up-
317
00:33:43,447 --> 00:33:47,804
When it's finished on one branch,
it releases a strand of silk
318
00:33:47,847 --> 00:33:50,919
and abseils down to the next-
319
00:34:11,847 --> 00:34:14,964
1t's a risky business
being a juicy, fat caterpillar-
320
00:34:15,007 --> 00:34:20,604
You're in danger of being spied by all
of those birds just back from migration-
321
00:34:29,567 --> 00:34:31,046
But the caterpillar has a plan-
322
00:34:32,407 --> 00:34:38,084
1t uses its silk to weave the needles
together and hide in a dense web-
323
00:34:45,447 --> 00:34:48,837
Now, the springtime assault
by these caterpillars
324
00:34:48,887 --> 00:34:51,003
is bad news for the trees-
325
00:34:51,047 --> 00:34:54,676
But for other inhabitants
of these forests,
326
00:34:54,727 --> 00:34:56,957
these caterpillars are heroes-
327
00:35:00,487 --> 00:35:03,365
It's thanks to the behaviour
of this species
328
00:35:03,407 --> 00:35:07,286
that one of North America's most elusive
and charismatic predators -
329
00:35:07,327 --> 00:35:08,760
the Canadian lynx -
330
00:35:08,807 --> 00:35:12,925
is enjoying a bit of a renaissance
in forests like this one.
331
00:35:14,127 --> 00:35:19,918
But the caterpillar lives all the way
up there, in the canopy.
332
00:35:19,967 --> 00:35:24,324
Whilst the cat with the pointed ears
is prowling around down here.
333
00:35:24,367 --> 00:35:27,677
So how can a humble insect like this
334
00:35:27,727 --> 00:35:31,276
have any impact
on a formidable thing like that?
335
00:35:31,327 --> 00:35:34,125
I bet the lynx never even sees
the caterpillar
336
00:35:34,167 --> 00:35:36,761
throughout the course of its life.
337
00:35:36,807 --> 00:35:39,799
Why does the lynx need the caterpillar?
338
00:35:42,087 --> 00:35:46,922
The clue is how they affect
the lynx's prey on the forest floor-
339
00:35:50,247 --> 00:35:54,479
For decades, scientists have studied
budworm caterpillars,
340
00:35:54,527 --> 00:35:57,200
and a remarkable pattern has emerged-
341
00:35:57,247 --> 00:36:02,958
They've discovered that the population
of caterpillars fluctuates dramatically-
342
00:36:03,007 --> 00:36:06,522
And at the peak of the cycle,
343
00:36:06,567 --> 00:36:10,480
there can be tens of thousands
of budworms in a single tree-
344
00:36:18,447 --> 00:36:21,519
And this has devastating consequences-
345
00:36:25,727 --> 00:36:28,480
Whilst these dramatic natural events
346
00:36:28,527 --> 00:36:32,202
might be a catastrophe
for the established trees,
347
00:36:32,247 --> 00:36:37,162
for anything trying to grow on the
forest floor, they are an absolute bonus.
348
00:36:37,207 --> 00:36:39,402
In here, where it's dark,
there's very little,
349
00:36:39,447 --> 00:36:43,565
very poor diversity -
just some mosses and a few ferns.
350
00:36:43,607 --> 00:36:45,484
But as soon as
there's a break in the canopy
351
00:36:45,527 --> 00:36:50,521
and the sunlight can flood in -
well, look at the difference.
352
00:36:50,567 --> 00:36:54,196
Lots of wild flowers, there's young maple
coming through here,
353
00:36:54,247 --> 00:37:00,595
mountain ash and, most importantly of all,
regenerating spruce and fir.
354
00:37:03,007 --> 00:37:08,525
Now, the hares essentially need
these regenerating conifers as shelter.
355
00:37:09,967 --> 00:37:14,279
And, of course, what's good for the hares
is also good for the lynx.
356
00:37:17,487 --> 00:37:21,560
1t's such an elegant connection-
357
00:37:21,607 --> 00:37:24,883
Without the spring emergence
of the hungry caterpillars
358
00:37:24,927 --> 00:37:27,316
to chew holes in the dense canopy,
359
00:37:27,367 --> 00:37:31,280
there wouldn't be enough light
flooding the forest floor-
360
00:37:31,327 --> 00:37:33,363
And with less light down here,
361
00:37:33,407 --> 00:37:39,277
there would be less growing for
our snowshoe hare to forage and hide in,
362
00:37:39,327 --> 00:37:41,795
and then there would be nothing
363
00:37:41,847 --> 00:37:46,967
for L 1-1 1 and all of those
hundreds of other lynx to eat-
364
00:37:47,007 --> 00:37:51,523
And that's why the lynx
needs the caterpillar.
365
00:37:51,567 --> 00:37:54,559
And now it's spring,
there's no better time
366
00:37:54,607 --> 00:37:58,282
to see what the future holds
for the lynx population-
367
00:38:15,647 --> 00:38:19,481
Wildlife biologist Jen is doing a count-
368
00:38:20,967 --> 00:38:24,846
She's detected a signal
from a radio-collared female-
369
00:38:42,047 --> 00:38:44,402
There she is-
370
00:38:44,447 --> 00:38:46,915
But there might be something else here-
371
00:38:52,167 --> 00:38:56,285
Safe inside a den, a lynx cub-
372
00:38:57,687 --> 00:38:59,917
He's just a few weeks old-
373
00:38:59,967 --> 00:39:01,400
(CUB SQUEAKS)
374
00:39:12,447 --> 00:39:14,677
His eyes aren't even open.
375
00:39:14,727 --> 00:39:18,242
Jen must work fast before Mum returns-
376
00:39:35,807 --> 00:39:40,756
Thanks to the timing of the budworm
opening the canopy this spring,
377
00:39:40,807 --> 00:39:45,119
there's going to be enough prey
for these lynx to hunt next winter-
378
00:39:47,567 --> 00:39:48,761
(CUB SQUEAKS)
379
00:40:02,447 --> 00:40:07,396
Far away to the west, the Raincoast forest
is coming back to life-
380
00:40:20,887 --> 00:40:24,880
Thanks to the richness
of the autumn salmon run,
381
00:40:24,927 --> 00:40:27,202
the bears have survived the winter-
382
00:40:32,967 --> 00:40:37,643
They've now returned to the forest,
looking for something to eat-
383
00:40:37,687 --> 00:40:41,202
They'll survive on vegetation
until the next salmon run-
384
00:40:46,727 --> 00:40:48,604
The emergence of the bears
385
00:40:48,647 --> 00:40:53,482
is a cue for scientists to conduct
a rather risky experiment-
386
00:40:53,527 --> 00:40:56,758
They need a large, hungry bear-
387
00:40:58,607 --> 00:41:00,598
1t's the only way to measure
388
00:41:00,647 --> 00:41:04,481
the impact of
all of those salmon on this ecosystem
389
00:41:04,527 --> 00:41:10,762
and to understand why this vast,
ancient forest has thrived for so long-
390
00:41:17,527 --> 00:41:19,722
For such a big question,
391
00:41:19,767 --> 00:41:26,400
the methods employed by senior researcher
Chris Darimont seem a bit curious-
392
00:41:28,687 --> 00:41:31,884
He's equipped
with a can full of old salmon guts,
393
00:41:31,927 --> 00:41:37,797
effusing probably
the most disgusting smell known to man-
394
00:41:37,847 --> 00:41:40,441
CHRIS: This is wonderful stuff.
395
00:41:44,047 --> 00:41:48,040
But he hopes
the bears are going to love it-
396
00:41:49,487 --> 00:41:51,318
He's made an aerial lure,
397
00:41:51,367 --> 00:41:56,566
so the wind will carry this distinctive
perfume deep into the forest-
398
00:41:56,607 --> 00:41:58,757
The wind - extra boost.
399
00:42:05,487 --> 00:42:10,242
Now they surround the area
with barbed wire-
400
00:42:10,287 --> 00:42:15,077
And it's this that they hope will collect
what they're so interested in -
401
00:42:15,127 --> 00:42:20,406
- a single hair from a visiting bear-
- (CAMERA BEEPS)
402
00:42:20,447 --> 00:42:24,599
Now the site is prepared,
it's time to set some remote cameras---
403
00:42:26,607 --> 00:42:29,360
---and beat a hasty retreat-
404
00:42:33,807 --> 00:42:37,800
Personally, 1'm very happy to watch
from a safe distance-
405
00:42:37,847 --> 00:42:41,760
1t's not the smell -
some of those bears are huge-
406
00:42:45,167 --> 00:42:47,158
Look at the size of this bear!
407
00:42:52,607 --> 00:42:56,236
As a trap, this is the perfect bait,
it's working brilliantly.
408
00:42:56,287 --> 00:42:57,640
The bears have come in
409
00:42:57,687 --> 00:43:00,963
and they're snagging themselves
on the wire there.
410
00:43:01,007 --> 00:43:04,283
You can see it vibrating about.
And that's justwhat we want.
411
00:43:06,207 --> 00:43:07,879
Fresh out of hibernation,
412
00:43:07,927 --> 00:43:11,078
it seems they can't resist
this pile of stinking salmon.
413
00:43:12,327 --> 00:43:15,683
This one's even rolling around
in the stuff now.
414
00:43:15,727 --> 00:43:18,195
No doubt it values the scent -
I'm not sure we would.
415
00:43:22,887 --> 00:43:26,197
The bear's coat has been growing
for nearly a year,
416
00:43:26,247 --> 00:43:28,681
but soon it will be moulted and lost-
417
00:43:32,207 --> 00:43:35,005
The more bears we can attract, the better-
418
00:43:46,367 --> 00:43:48,198
Now the coast is clear,
419
00:43:48,247 --> 00:43:51,796
and it's time to retrieve any fur
from the barbed wire-
420
00:43:57,847 --> 00:44:04,446
So what on Earth can hair tell us
about this forest ecosystem?
421
00:44:10,767 --> 00:44:12,678
Well, hair is made of protein
422
00:44:12,727 --> 00:44:17,517
sourced from whatever the bear
has been eating over the last year-
423
00:44:29,207 --> 00:44:31,402
And by analysing this hair,
424
00:44:31,447 --> 00:44:36,601
science can reveal an astonishing level
of detail about a bear's life-
425
00:44:44,367 --> 00:44:48,485
We can learn so much
from a single bear's hair.
426
00:44:48,527 --> 00:44:52,884
So I know, for instance, that this one
has come from a female grizzly.
427
00:44:52,927 --> 00:44:56,044
I know exactly what it's been eating
even on a week-by-week basis,
428
00:44:56,087 --> 00:45:00,524
where that food has come from and even
the impact on the quality of its life.
429
00:45:00,567 --> 00:45:03,604
So this bear has been getting
most of its protein,
430
00:45:03,647 --> 00:45:06,161
not from the forest around here
431
00:45:06,207 --> 00:45:10,200
but actually from the deep ocean,
via the salmon.
432
00:45:10,247 --> 00:45:13,159
And we know that,
throughout the course of the year,
433
00:45:13,207 --> 00:45:17,166
80%/ of that bear's protein
has come from these salmon.
434
00:45:17,207 --> 00:45:19,323
And that's surprising, because, remember,
435
00:45:19,367 --> 00:45:23,679
they're only available to the bear
for a few weeks during the autumn.
436
00:45:23,727 --> 00:45:26,924
And yet the impact
is clearly lasting all year.
437
00:45:28,447 --> 00:45:32,679
So how come the bears appear to be
so full of salmon?
438
00:45:43,567 --> 00:45:45,080
Well, back in autumn,
439
00:45:45,127 --> 00:45:49,917
we saw the bears scattering fish carcasses
all around the forest floor-
440
00:45:58,047 --> 00:46:01,357
As the protein
in those rotting salmon broke down,
441
00:46:01,407 --> 00:46:05,116
nitrogen from it accumulated in the soil-
442
00:46:05,167 --> 00:46:08,557
And this salmon nitrogen
is like fertilizer-
443
00:46:13,327 --> 00:46:17,115
So in spring,
nutrients all the way from the ocean
444
00:46:17,167 --> 00:46:20,955
gradually appear
in all the vegetation growing here-
445
00:46:23,047 --> 00:46:27,916
Just in time for the hungry bears to eat
as they emerge from hibernation-
446
00:46:30,527 --> 00:46:33,803
And hungry bears have huge appetites -
447
00:46:33,847 --> 00:46:37,157
they'll eat a third of their body weight
every day-
448
00:46:40,087 --> 00:46:44,956
That's why their bodies
appear to contain so much salmon-
449
00:46:54,247 --> 00:46:57,523
But the impact
of this ocean-borne nitrogen
450
00:46:57,567 --> 00:47:00,718
extends far beyond bears and their food-
451
00:47:04,327 --> 00:47:09,162
This particular form of nitrogen
can be found in almost all of the animals
452
00:47:09,207 --> 00:47:11,801
and plants that appear here in the spring-
453
00:47:21,967 --> 00:47:26,518
These rufous hummingbirds
have migrated to the forest to breed-
454
00:47:26,567 --> 00:47:31,197
They're drinking nectar from plants
that have been fertilized by rotted fish-
455
00:47:31,247 --> 00:47:35,399
So they'll carry the same salmon nutrients
with them
456
00:47:35,447 --> 00:47:37,039
as they fly through the forest-
457
00:47:44,607 --> 00:47:48,998
And many of the insects
pollinating the plants now
458
00:47:49,047 --> 00:47:52,005
were incubated in that decaying flesh
back in the autumn-
459
00:47:54,687 --> 00:47:56,006
As they themselves are eaten,
460
00:47:56,047 --> 00:48:00,484
the salmon nutrients
are spread even further-
461
00:48:03,967 --> 00:48:07,243
Thanks to the bears, the insects
and the birds,
462
00:48:07,287 --> 00:48:12,236
this salmon fertilizer is spread
deeper and deeper into the forest,
463
00:48:12,287 --> 00:48:16,166
sometimes as much as 800 metres
from the river.
464
00:48:16,207 --> 00:48:19,199
And this pulse of nutrients
465
00:48:19,247 --> 00:48:24,162
then allows the organisms which define
the forest itself to prosper...
466
00:48:25,287 --> 00:48:26,959
...its trees.
467
00:48:42,327 --> 00:48:46,923
Dr Tom Reimchen
can measure exactly how much
468
00:48:46,967 --> 00:48:49,845
these vast old trees need the fish-
469
00:48:52,447 --> 00:48:58,317
The secret is to look inside the tree
by taking a core sample-
470
00:49:06,727 --> 00:49:12,279
Written on it is the entire story
of this 3OO-year-old tree-
471
00:49:18,447 --> 00:49:22,998
T0M: The rings I see are two, three,
even four millimetres,
472
00:49:23,047 --> 00:49:28,917
which continues back to even the early
parts of the 1 800s, late 1 700s.
473
00:49:31,287 --> 00:49:35,200
Tom has taken similar samples
from thousands of trees-
474
00:49:36,287 --> 00:49:39,916
An entire forest is lined up in his lab,
475
00:49:39,967 --> 00:49:42,800
each tree waiting to tell its own story-
476
00:50:02,967 --> 00:50:07,802
1n this seasonal climate, annual rings
are created as the tree grows-
477
00:50:13,687 --> 00:50:17,362
From these rings, he can determine
not just the age of the tree
478
00:50:17,407 --> 00:50:20,524
but also the amount of growth
in each year-
479
00:50:22,407 --> 00:50:24,875
Some of the rings are thicker than others,
480
00:50:24,927 --> 00:50:27,043
showing that the tree has grown more-
481
00:50:33,927 --> 00:50:38,717
Like the bear fur,
each annual ring can be analysed-
482
00:50:38,767 --> 00:50:41,884
Tom can search
for the same type of nitrogen
483
00:50:41,927 --> 00:50:44,361
that's found in the bears'hairs -
484
00:50:44,407 --> 00:50:49,800
it comes from the ocean
and it's called nitrogen-1 5-
485
00:50:55,647 --> 00:50:58,286
And the data will tell us
486
00:50:58,327 --> 00:51:04,357
just how much nitrogen in those trees
comes from all those salmon-
487
00:51:09,927 --> 00:51:12,999
I think this is really exciting.
488
00:51:13,047 --> 00:51:15,641
You see, the annual growth rings here
489
00:51:15,687 --> 00:51:19,362
show the presence
of the stable isotope nitrogen-1 5,
490
00:51:19,407 --> 00:51:22,877
which significantly comes from the oceans.
491
00:51:22,927 --> 00:51:26,363
It could only have been carried here
by the salmon.
492
00:51:26,407 --> 00:51:28,841
Now, look. Here is the present,
493
00:51:28,887 --> 00:51:33,165
the bark on the outside of a tree.
So these rings here represent perhaps
494
00:51:33,207 --> 00:51:35,960
about the last 1 5 years
and they're very closely packed together.
495
00:51:36,007 --> 00:51:40,956
But here, back in the 1 980s,
the rings are twice as thick.
496
00:51:41,007 --> 00:51:45,603
The trees have been growing twice
as much during the course of a year.
497
00:51:45,647 --> 00:51:49,276
So perhaps the salmon runs then
were even more productive
498
00:51:49,327 --> 00:51:51,557
than they have been recently.
499
00:51:51,607 --> 00:51:53,040
But that's not the best thing.
500
00:51:53,087 --> 00:51:55,043
Come and have a look at this.
501
00:51:55,087 --> 00:52:00,161
By measuring the abundance of that
nitrogen isotope in this material,
502
00:52:00,207 --> 00:52:05,440
I can tell you that majestic old giants
like this beauty here
503
00:52:05,487 --> 00:52:13,326
are actually composed of up to
85%/ material that's derived from salmon.
504
00:52:15,287 --> 00:52:20,839
Now, when I was a teenager, I remember
learning that I was made of carbon,
505
00:52:20,887 --> 00:52:23,765
and carbon could only be formed
when stars died.
506
00:52:23,807 --> 00:52:28,881
Effectively, I was made of dead stars,
and that struck me as terribly romantic.
507
00:52:28,927 --> 00:52:34,445
But look at this.
This is a forest made of the ocean!
508
00:52:35,607 --> 00:52:39,202
That's why the tree needs the fish.
509
00:52:42,327 --> 00:52:45,478
Without this
unlikely sounding relationship,
510
00:52:45,527 --> 00:52:51,238
this magnificent ancient forest
just wouldn't be the place it is today-
511
00:52:53,487 --> 00:52:56,081
But there is one more relationship
512
00:52:56,127 --> 00:52:59,597
crucial to seasonal forest
all around the world
513
00:52:59,647 --> 00:53:03,435
when it comes to surviving
constant change-
514
00:53:05,167 --> 00:53:09,080
And it's one that reaches
its greatest intensity now,
515
00:53:09,127 --> 00:53:10,640
at the height of summer-
516
00:53:14,087 --> 00:53:18,603
1t's the driest time of year,
and the trees need water-
517
00:53:20,767 --> 00:53:24,442
Fortunately,
united with their fungal partners,
518
00:53:24,487 --> 00:53:28,036
the trees
have massively extended their roots-
519
00:53:28,087 --> 00:53:30,647
Fungal threads in the soil
are absorbing water
520
00:53:30,687 --> 00:53:32,439
and passing it to the tree-
521
00:53:35,247 --> 00:53:38,000
But what has only recently
been discovered
522
00:53:38,047 --> 00:53:41,926
is the sheer scale
of these fungal root networks-
523
00:53:43,887 --> 00:53:47,516
A single cubic centimetre of the soil here
524
00:53:47,567 --> 00:53:53,164
can have a mile of these
white fungal threads running through it -
525
00:53:53,207 --> 00:53:56,438
they're called mycorrhizae.
526
00:53:56,487 --> 00:53:57,886
And for me,
527
00:53:57,927 --> 00:54:02,557
it's these organisms that are
the real secret of the forest here.
528
00:54:04,847 --> 00:54:05,836
1n the lab,
529
00:54:05,887 --> 00:54:10,722
the genetic fingerprints of individual
mycorrhizae have been identified-
530
00:54:17,727 --> 00:54:21,766
By mapping an area 3O metres across,
it's been discovered
531
00:54:21,807 --> 00:54:26,835
that individual fungi
connect to more than a single tree-
532
00:54:28,607 --> 00:54:30,325
Just one fungus
533
00:54:30,367 --> 00:54:34,679
can be joined to 8O%
of all of the plants growing here-
534
00:54:36,767 --> 00:54:40,316
And, amazingly, these physical links
535
00:54:40,367 --> 00:54:45,999
enable different species of plants
to exchange nutrients-
536
00:54:46,047 --> 00:54:51,326
Older established plants
are even nurturing younger weaker ones-
537
00:54:51,367 --> 00:54:54,325
1t acts like
an underground welfare system-
538
00:54:56,247 --> 00:55:01,367
These giant webs connect all of the trees
in this forest,
539
00:55:01,407 --> 00:55:06,720
and keep them, and all of the things
that are dependent upon them, alive.
540
00:55:06,767 --> 00:55:11,841
That's why scientists
are calling this the wood-wide web.
541
00:55:23,527 --> 00:55:27,998
1t's thanks to this natural phenomenon,
the wood-wide web,
542
00:55:28,047 --> 00:55:33,075
that together the trees
in the forest ecosystems are resilient-
543
00:55:34,367 --> 00:55:38,201
Resilient enough to cope
with the dramatic changes
544
00:55:38,247 --> 00:55:40,283
they encounter every year-
545
00:55:49,407 --> 00:55:52,763
And what's really amazing
is how the web is built-
546
00:55:56,767 --> 00:56:00,885
It's thanks to hungry mammals
like our flying squirrels
547
00:56:00,927 --> 00:56:05,796
that this essential life-support system
is effectively maintained.
548
00:56:07,207 --> 00:56:12,042
It's actually fair to say that these trees
wouldn't be standing here,
549
00:56:12,087 --> 00:56:17,480
wouldn't be thriving,
unless a squirrel had eaten a truffle.
550
00:56:17,527 --> 00:56:19,643
And thatis fantastic!
551
00:56:23,607 --> 00:56:25,006
1t is fantastic-
552
00:56:25,047 --> 00:56:29,165
1t's fantastic to think
that what animals do in one season
553
00:56:29,207 --> 00:56:33,917
influences the forest ecosystem
throughout the year-
554
00:56:38,247 --> 00:56:43,799
1t's almost as if all of these stories
are choreographed-
555
00:56:46,687 --> 00:56:49,997
The arrival of the salmon
at exactly the right time
556
00:56:50,047 --> 00:56:52,356
to fatten the bears for winter.
557
00:56:53,567 --> 00:56:57,242
Then the emergence
of the lush green vegetation
558
00:56:57,287 --> 00:57:02,486
fertilized by those salmon to sustain the
bears when they emerge from hibernation.
559
00:57:02,527 --> 00:57:07,601
The squirrels foraging for truffles
in the autumn time,
560
00:57:07,647 --> 00:57:10,241
and sowing their spores
throughout the forest
561
00:57:10,287 --> 00:57:16,442
to grow a fungal network that joins
all of the trees and all of the plants,
562
00:57:16,487 --> 00:57:18,762
and provides them with nutrients.
563
00:57:19,887 --> 00:57:24,881
The budworm chewing a hole
in springtime in the canopy,
564
00:57:24,927 --> 00:57:29,876
so that in summer, sunlight floods down
to the forest's floor
565
00:57:29,927 --> 00:57:34,079
and produces the perfect hunting habitat
for lynx.
566
00:57:35,127 --> 00:57:36,719
It's all in the timings.
567
00:57:37,767 --> 00:57:41,442
And it's this that makes
these temperate forests
568
00:57:41,487 --> 00:57:43,842
such magical places.
569
00:58:01,687 --> 00:58:06,158
If you'd like to know more about the
fascinating web of links between species,
570
00:58:06,207 --> 00:58:11,759
the 0pen University has produced some
material both to inform and inspire you.
571
00:58:11,807 --> 00:58:16,517
For your free copy, or to find out more
about 0pen University programmes, ring...
572
00:58:21,807 --> 00:58:23,479
0r go to the website...
573
00:58:27,127 --> 00:58:29,197
And then follow the links
to 0pen University.
574
00:58:31,127 --> 00:58:34,597
And join me next time
when 1'll be travelling
575
00:58:34,647 --> 00:58:37,320
to some of the world's
greatest water habitats-
51039
Can't find what you're looking for?
Get subtitles in any language from opensubtitles.com, and translate them here.