WEBVTT

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[TED intro plays]

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Have you ever wondered what it's like
to be a tree?

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Nobody.
[audience laughs]

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Ah, there's somebody.

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See, I thought it was just me,

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but for me, I think--

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Oh, there's more of you out there.

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But I think for me,
it's actually a side effect of my job.

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I work on mountain pine beetle,

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and this insect has the dubious honor
of having developed,

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over just the last few years,
what is very likely

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to be the largest insect outbreak
ever recorded by humans

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on the planet.

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And this tiny little insect,

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the size and appearance
of a mouse turd,

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has managed to kill millions
and, in fact, billions of trees

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across vast landscapes.

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Now, when I'm out working in the forest,

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I actually do think about what it means
to be a tree.

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Now, obviously,
they're quite different from us.

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They're made of wood;
we're made of flesh and blood,

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but I see another big difference.

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Trees can't walk.

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Trees can't run.

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And trees can't hide.

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And that means

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that when a enemy
like mountain pine beetle shows up,

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they have no choice

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but to stand their ground.

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Now, most of us,
when we think about trees,

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we think about
these nice, gentle, passive,

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benign organisms,

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but nothing could be further
from the truth.

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Trees

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are dangerous.

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[laughter]

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I see some skeptics out there,

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but really, put yourself
in the place of a tree.

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What would you do?

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Would you just stand there?

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Would you fight back?

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You'd fight back.

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And that's exactly what trees do.

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Trees are armed
with an amazing array

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of physical and chemical weapons.

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They fight back,
and they fight back really hard.

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So if you're a mountain pine beetle,

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trees pose a significant challenge.

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In fact, it takes hundreds

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and sometimes even thousands
of beetles

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to kill a single tree.

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Now,

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if not enough beetles show up,

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that's a dangerous situation,

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because that means the tree wins
and the beetles die.

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So it's actually very risky

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to be a mountain pine beetle,

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and even when they're successful,

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it hardly seems worth the effort.

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Trees
are the epitome of junk food.

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Woody tissues have almost no nutrients,

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and beetles can't live on wood
much easier than we can.

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So how do they do it?

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Well, guess what,
they do it the same way we do.

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When they've been eating a lot--
well,

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when we've been eating
a lot of junk food,

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we pile on those nutritional supplements,

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and that's exactly what they do,

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only in a very different way
as you might suspect.

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The beetles actually partner
with a couple of fungi

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that provide to them
everything that wood cannot:

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vitamins,
nitrogen to make proteins,

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sterols to make hormones,
and so forth.

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Pretty cool.

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By partnering with fungi,

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beetles can use trees
to raise their kids,

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but being able to use a tree for food

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is just the first step
in developing an outbreak.

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What is it
that actually allows these beetles

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to develop such huge numbers

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that they can kill you,
if you're a tree,

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and your family
and your friends

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and, in fact, the entire forest?

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Well, you'll hear from a lot of people

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that the reason we have this big outbreak

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is because we have unhealthy forests,

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or because we have too many pines,

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or because we have too many big pines,

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or too many lodgepole pines,

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that if we had only managed our forest,

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none of this would have happened.

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But that's not exactly true.

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As you might suspect,

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there's a little bit more
to that story.

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So let me explain
how this big outbreak developed

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and why this one
is so unusual

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compared to those that we've seen
in the past.

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First, you need to know a little bit
about the insect.

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One thing,
outbreaks aren't new.

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Mountain pine beetle is actually native
to western North America,

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and it's been developing outbreaks there
for millennia,

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and these outbreaks
are actually natural disturbances.

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They help maintain and restore
the forest.

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But, clearly,

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beetles are not in outbreaks
all the time.

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They only develop outbreaks
every few decades or centuries,

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and only when you have two things:

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you need to have lots of pines
on the landscape

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that are big enough
for the beetles to use,

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which is a condition we always have,

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and a trigger.

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So let me explain this trigger.

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What you see here
is what a mountain pine beetle population

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might look like
for a couple of hundred years,

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and what you can see
is that the beetle

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is present in very low numbers
most of the time.

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And so at this point,
if you're a tree,

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you should feel very safe,

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because the beetles are actually

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at the mercy
of their own low numbers.

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There are so few of them out there,

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they can hardly ever kill a tree,

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and those few trees they actually kill
have disease or they're damaged

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and can't fight back.

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But of course,
somewhere along the way,

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we get a trigger,

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and for mountain pine beetle,
the trigger

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is a change in climate

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to warmer and drier conditions.

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And at this point,
if you're a tree,

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you should start to worry

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because warmer temperatures

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allow greater productivity
of beetle young

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and greater survival
of their young over the winter,

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and that means more beetles,

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and drought stresses trees,

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and that lowers their defenses,

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and that lowers the numbers
of beetles it takes to kill them.

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And very importantly,
drought stresses trees across regions,

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so that's really big areas.

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So if you're a tree,

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this
is a really bad combo.

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It means
you've got a lot of beetles out there,

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but it doesn't take very many
to kill a tree,

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and there's lots and lots and lots
of trees

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that are easy to kill.

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This situation allows the beetles
to rapidly build in population

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until they reach a threshold

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over which there are so many beetles

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that they can even kill
healthy, defensive trees.

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At this point,

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tree defenses are inconsequential.

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They no longer matter.

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And, in fact, the beetles switch

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to attacking healthy trees

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because they're better food
for their young,

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and better food for the young means...

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more beetles.

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At this point,
the outbreak is self-perpetuating,

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and there's virtually nothing you can do
to stop it.

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Now, once an outbreak initiates,

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there's a couple
of potential end points.

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One,
it can go to completion,

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and that means that they--
the beetles,

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kill most of the suitable trees
on the landscape,

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and then their populations crash

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because they're out of food.

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But in the past,
this seldom ever happened.

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You had the initiation of an outbreak

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when you had
an abnormally warm, dry period,

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but when things went back to normal,

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got cooler and wetter,

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then tree defenses came up;

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beetle productivity went down,

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and the beetles pooped out.

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But the problem now is, of course,

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that we're not expecting to go back

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to cooler, wetter conditions.

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The predictions
are we're going to get warmer

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and in many places drier,

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and that means
that going to completion

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might be the new norm.

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And if that's the case,
we need to be really concerned,

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because that means really big changes

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in our forest ecosystems,

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and of course, then,
big changes in all those services

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and functions that they provide.

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Now, the current outbreak

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is actually, or maybe,
a harbinger of things to come.

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This outbreak is significantly different

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than any we've seen in the past.

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For one, it's <i>ten</i> times bigger,

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ten times.

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Now, that's pretty remarkable
in and of itself.

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But there's more.

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The beetle is actually on the move.

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Because of warming,
the beetle has moved

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several hundred kilometers
further north in Canada,

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and it's now all the way to the Yukon.

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It has jumped the Northern Rockies

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and has spread across Alberta

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and is now even invading Saskatchewan.

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In this location in Canada,

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the beetle
is in a new place;

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it's in a new species of tree,

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and that makes it an exotic.

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And we know that exotics

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are seldom very good

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for our native ecosystems.

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The beetle is expected to continue
to move across the continent,

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through the boreal forest

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and into our eastern pine forests.

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Because of warming,
the beetle has also moved up in elevation

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where it's wiping out white bark pine.

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This is a tree that used to be protected
from the beetle by cold,

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but now the devastation
is so extensive and severe,

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this critically important tree

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is now being recommended for listing

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as an endangered species.

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And all of this
has been due

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to a warming climate.

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Now, I mentioned
that this particular outbreak

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is far outside the historic norm,

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and as such, in many locations,

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the beetle is no longer restorative
for the forest,

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but damaging.

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Effects on water,
vegetation,

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wildlife,
local communities,

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and economies
have been massive.

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And human responses,

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for better or for worse,
to the outbreak

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have added an additional level
of impact.

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At this point,

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if you're a tree,

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you should not only be worried;

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you should be shaking
in your roots.

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[person laughs]
Sorry, bad one.

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[laughter]

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Couldn't help it.

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But, also, if you think about this--
this outbreak,

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it's really tempting to think of it
as a local issue:

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It's just western North America,

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but actually, the implications
are global.

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Trees are incredibly important sinks
for carbon,

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but when vast areas die,

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they become sources.

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In the worst year of the outbreak,

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carbon emissions from beetle kill
in British Columbia alone

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are predicted
to have equaled the carbon releases

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from fires
across all of Canada

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for the preceding forty years.

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Those kinds of carbon releases

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obviously can feed back
to affect humans

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and ecosystems
all around the world.

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Now something else
to actually think about as well

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with mountain pine beetle
is to realize

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that this situation is not unique.

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Climate-driven tree die-offs
are happening right now

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all over the world.

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Take, for example,
the giant Euphorbia tree

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that I work on in Africa.

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It's being mass attacked
by ambrosia beetles.

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These are tiny, little beetles

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related to the mountain pine beetle,

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but they're typically not a problem.

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But because of increasing temperature,

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decreasing precipitation,

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these trees are stressed,

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and the beetles are responding.

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This iconic poison arrow tree
of Africa

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is very likely to disappear

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from many portions of its range

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just over the next decade.

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The massive piñon bark beetle ips
in the southwestern US

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has been so severe and extensive

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that many of these forests
are not expected to recover.

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Over eighty tree species
around the world

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are known to be in trouble
due to climate change,

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and likely there's a whole lot more

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that we haven't yet recognized.

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So, what do we do?

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What do you do?

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What do I do?

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What do the trees do?

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Well, unfortunately,
we can't just go out there somewhere

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and turn down a thermostat.

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We can't lay out

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thousands and thousands of miles
of irrigation,

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even if we could come up
with the water.

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And logging won't do much
if it's driven by climate.

00:13:12.240 --> 00:13:15.329
So we need to finally go
to the root of the problem

00:13:15.330 --> 00:13:18.449
and do something about our emissions
of greenhouse gasses,

00:13:18.450 --> 00:13:20.489
and we need to do it soon.

00:13:20.490 --> 00:13:24.599
We also need to develop
new tools and approaches to our forests.

00:13:24.600 --> 00:13:26.009
We need to move away from thinking

00:13:26.010 --> 00:13:28.169
that logging will fix everything,

00:13:28.170 --> 00:13:30.059
and we need to start working
with our knowledge

00:13:30.060 --> 00:13:33.119
of genetics and adaptation.

00:13:33.120 --> 00:13:37.169
And very importantly,
we need to remember

00:13:37.170 --> 00:13:39.109
that trees can't walk;

00:13:39.110 --> 00:13:41.039
trees can't run,

00:13:41.040 --> 00:13:43.209
and trees can't hide,

00:13:43.210 --> 00:13:45.299
and with increasing stress,

00:13:45.300 --> 00:13:49.855
trees are going to have fewer
and fewer defenses at their disposal,

00:13:49.856 --> 00:13:53.009
and somehow it's going to be up to us
to get them through.

00:13:53.010 --> 00:13:56.328
I hope I've opened some eyes
and minds tonight about the threat

00:13:56.329 --> 00:13:59.399
that a warming climate poses
to our forests,

00:13:59.400 --> 00:14:02.189
but I also hope
I've helped people recognize

00:14:02.190 --> 00:14:05.684
that these threats are not just
through effects on the big things,

00:14:05.685 --> 00:14:07.194
like ice shelves

00:14:07.195 --> 00:14:08.509
and sea level rise

00:14:08.510 --> 00:14:09.949
and extreme weather,

00:14:09.950 --> 00:14:12.389
but through their effects
on the little things,

00:14:12.390 --> 00:14:14.249
like a tiny little insect

00:14:14.250 --> 00:14:15.808
the size and appearance

00:14:15.809 --> 00:14:17.429
of a mouse turd.

00:14:17.430 --> 00:14:19.851
Thank you.

00:14:19.852 --> 00:14:22.525
[applause]