Why wildfires have gotten worse -- and what we can do about it | Paul Hessburg

翻译人员: Hong Li 校对人员: Yang Tao

As you've probably noticed,

大家可能注意到了，

in recent years, a lot of western forests have burned

近几年，西部很多森林爆发了

in large and destructive wildfires.

大规模毁灭性的火灾。

If you're like me --

你们可能跟我一样，

this western landscape is actually why my family and I live here.

西部的森林正是吸引我和我的家人 生活在那里的原因。

And as a scientist and a father,

作为一名科学家，一名父亲，

I've become deeply concerned about what we're leaving behind

我为我们留给子孙后代的东西 感到深深的担忧，

for our kids, and now my five grandkids.

为我的孩子，还有我的5个孙辈。

In the US, an area that's larger than the state of Oregon has burned

在美国，仅仅过去10年间， 就有相当于俄勒冈州这么大的面积

in just the last 10 years,

被火灾烧毁，

and tens of thousands of homes have been destroyed.

数万的房屋被毁。

Acres burned and homes destroyed have steadily increased

火灾面积和被毁房屋数量 在过去30年间

over the last three decades,

一直在持续增长，

and individual fires that are bigger than 100,000 acres --

着火面积超过405平方公里的 单场火灾数量

they're actually on the rise.

也在增长。

These are what we call "megafires."

我们称之为“大型火灾”。

Megafires are the result of the way we've managed this western landscape

大型火灾是过去150年间， 我们在持续变暖的气候下

管理这美丽的西部森林

over the last 150 years

in a steadily warming climate.

所导致的后果。

Much of the destruction that we are currently seeing

很多我们如今看到的灾难

could actually have been avoided.

本来是可以避免的。

I've spent my entire career studying these western landscapes,

我整个职业生涯 都在研究西部的森林，

and the science is pretty clear:

其中的科学道理其实很简单：

if we don't change a few of our fire-management habits,

如果我们不改变一些防火习惯，

we're going to lose many more of our beloved forests.

我们还将失去更多珍爱的森林。

Some won't recover in our lifetime

其中一些可能在我们这一代，

or my kids' lifetime.

甚至是下一代都无法恢复。

It's time we confront some tough truths about wildfires,

我们要面对森林火灾的 几个残酷事实，

and come to understand that we need to learn to better live with them

要明白，我们需要学会适应它，

and change how they come to our forests,

如何改变它来临的方式， 无论是对森林，

our homes

对我们的家，

and our communities.

还是对我们的社区。

So why is this happening?

那么森林火灾是怎么发生的呢？

Well, that's what I want to talk to you about today.

这正是我今天要讲的。

You see this forest?

看到这片森林了吗？

Isn't it beautiful?

真是漂亮极了。

Well, the forests that we see today

我们今天看到的森林

look nothing like the forests of 100 or 150 years ago.

与100到150年前的 森林完全不同。

Thankfully, panoramic photos were taken in the 1930s

幸亏在30年代， 数以千计的西部山区防火员

from thousands of western mountaintop lookouts,

拍下了许多全景照片，

and they show a fair approximation

能让我们一窥所继承的森林的

of the forest that we inherited.

大致情况。

The best word to describe these forests of old is "patchy."

形容这些森林最好的一个词 就是“参差不齐”。

The historical forest landscape was this constantly evolving patchwork

历史上的森林景观 就是这种不断发展的块状区域，

of open and closed canopy forests of all ages,

里面是各个时期的森林，疏密相间，

有许多火灾的痕迹。

and there was so much evidence of fire.

And most fires were pretty small by today's standards.

如果按今天的标准来看， 大部分火灾都很小。

And it's important to understand that this landscape was open,

很重要的一点， 这些森林间是有空隙的，

with meadows and open canopy forests,

中间有草地，树林疏密相间，

and it was the grasses of the meadows

是这些林间草地

and in the grassy understories of the open forest

和位于树林间的落叶层

that many of the wildfires were carried.

承受了大部分的火灾。

There were other forces at work, too, shaping this historical patchwork:

还有其他的力量 也对造成这种块状区域起了作用：

for example, topography, whether a place faces north or south

比如地形，是朝南还是朝北，

or it's on a ridge top or in a valley bottom;

是在山脊还是在谷底，

elevation, how far up the mountain it is;

还有海拔，也就是山的高度，

and weather, whether a place gets a lot of snow and rain,

还有天气，是否有大量雨雪，

sunlight and warmth.

日照和气温。

These things all worked together

这些因素共同作用

决定了森林生长的方式。

to shape the way the forest grew.

And the way the forest grew shaped the way fire behaved

而森林生长的方式 又决定了火灾

on the landscape.

如何对地貌产生影响。

There was crosstalk between the patterns and the processes.

模式和过程互相交织，相互干扰。

You can see the new dry forest.

大家看新的干燥森林。

Trees were open grown and fairly far apart.

树是开放生长的， 树之间的空隙比较大。

Fires were frequent here, and when they occurred,

火灾在这个区域经常发生，

they weren't that severe,

但并不会很严重，

while further up the mountain,

再往山上走，

in the moist and the cold forests,

在潮湿和寒冷的森林里，

trees were more densely grown and fires were less frequent,

树木生长密集，火灾频率不高，

but when they occurred, they were quite a bit more severe.

但是一旦发生，就会更加严重。

These different forest types, the environments that they grew in

森林的种类不同，生长环境不同，

and fire severity -- they all worked together

还有火灾的严重程度， 这些因素交织在一起，

to shape this historical patchwork.

共同形成了历史区块。

And there was so much power

这种区块的作用

in this patchwork.

非常强大。

It provided a natural mechanism

它是一种天然的防御机制

to resist the spread of future fires across the landscape.

防止未来的火灾蔓延到整个森林。

Once a patch of forest burned,

一旦某一个区块的森林着火了，

it helped to prevent the flow of fire across the landscape.

它能防止火灾蔓延到别的区块。

A way to think about it is,

换句话说，

the burned patches helped the rest of the forest

着火的区块拯救了剩下的森林，

to be forest.

让它们得以延续。

Let's add humans to the mix.

让我们加入人类的影响。

For 10,000 years, Native Americans lived on this landscape,

1万年来，美洲原住民生活在这里，

and they intentionally burned it -- a lot.

他们焚烧了大片森林。

They used fire to burn meadows and to thin certain forests

他们焚烧草地，把森林变得稀疏，

so they could grow more food.

这样可以种更多粮食。

They used fire to increase graze

他们增加牧草，

for the deer and the elk and the bison that they hunted.

用来喂养捕猎来的鹿、麋鹿和野牛。

And most importantly, they figured out

最重要的是，他们发现，

if they burned in the spring and the fall,

如果他们在春季和秋季焚烧的话，

they could avoid the out-of-control fires of summer.

就可以避免在夏季 出现无法控制的大火。

European settlement -- it occurred much later, in the mid-1800s,

欧洲移民——这已经是 很久以后的事儿了，在19世纪中叶，

and by the 1880s, livestock grazing was in high gear.

在19世纪80年代， 畜牧业发展很快，

I mean, if you think about it, the cattle and the sheep ate the grasses

想象一下，牛羊吃掉的草

which had been the conveyer belt for the historical fires,

是历史上那些火灾的传送带，

and this prevented once-frequent fires from thinning out trees

它们阻止了日渐稀薄的森林中 曾经频发的火灾，

and burning up dead wood.

并且清除死掉的树木。

Later came roads and railroads, and they acted as potent firebreaks,

然后公路和铁路出现了， 它们是有效的防火道，

interrupting further the flow of fire across this landscape.

能防止火灾蔓延到整片森林。

And then something happened which caused a sudden pivot

之后发生了一件事情，

in our society.

彻底改变了我们的社会。

In 1910, we had a huge wildfire.

1910年，发生了一场巨大的火灾。

It was the size of the state of Connecticut.

着火面积有康涅狄格州那么大。

We called it "the Big Burn."

我们称之为“大火灾”。

It stretched from eastern Washington to western Montana,

它从华盛顿东部一直蔓延到 蒙大拿州西部，

and it burned, in a few days, three million acres,

在短短几天内， 它烧毁了约12000平方公里的土地，

devoured several towns, and it killed 87 people.

毁掉了许多村庄，有87人丧生。

Most of them were firefighters.

大部分是消防员。

Because of the Big Burn, wildfire became public enemy number one,

因为这场大火灾，森林火灾成为了 公众的头号敌人，

and this would shape the way that we would think about wildfire

这件事改变了我们整个社会

in our society

在接下来100年里

for the next hundred years.

对于森林大火的看法。

Thereafter, the Forest Service, just five years young at the time,

之后，刚刚成立5年的 国家森林局，

was tasked with the responsibility of putting out all wildfires

承担起了在78万 平方公里的公共土地上

on 193 million acres of public lands,

扑灭火灾的责任，

and they took this responsibility

他们将这项责任

看得很重。

very seriously.

They developed this unequaled ability to put fires out,

他们发展出了灭火的超级能力，

and they put out 95 to 98 percent

扑灭了每年发生在美国的

of all fires every single year in the US.

火灾中的95%-98%。

And from this point on, it was now fire suppression

从那时开始，森林的主要塑形者

and not wildfires

就不再是森林大火，

that would become a prime shaper of our forests.

而是对森林大火的压制。

After World War II, timber harvesting got going in the west,

二战过后，伐木业开始进入西部，

and the logging removed the large and the old trees.

砍伐掉了许多巨大而古老的树木。

These were survivors of centuries of wildfires.

它们是几个世纪以来 森林大火的幸存者。

And the forest filled in.

新的森林补充进来。

Thin-barked, fire-sensitive small trees filled in the gaps,

是那些树皮很薄，容易着火的小树，

and our forests became dense, with trees so layered and close together

我们的森林变得浓密， 层层叠叠，距离很近，

that they were touching each other.

互相紧挨着。

So fires were unintentionally blocked by roads and railroads,

于是大火无意中 被公路和铁路阻断，

the cattle and sheep ate the grass,

牛羊吃光了林间的草地，

then along comes fire suppression and logging, removing the big trees,

对火灾的压制 以及被伐木业移除的大树，

and you know what happened?

结果怎么样？

All these factors worked together

所有这些因素叠加在一起

to allow the forest to fill in,

让新的森林补充进来，

creating what I call the current epidemic of trees.

我称之为“树木成灾”。

(Laughter)

（笑声）

Go figure.

想想吧。

(Laughter)

（笑声）

More trees than the landscape can support.

树木的数量超出了 森林的承受范围。

So when you compare what forests looked like 100 years ago and today,

所以比较一下100年前 和现在的森林，

the change is actually remarkable.

变化还是很大的。

Notice how the patchwork has filled in.

看这些区块是如何形成的。

Dry south slopes --

南边干燥的斜坡，

they're now covered with trees.

现在已经长满了树。

A patchwork that was once sculptured by mostly small

这些区块曾经是因为小型

and sort of medium-sized fires

或者中型的火灾形成的，

has filled in.

如今已经长满了树。

Do you see the blanket of trees?

看到这一层由树木组成的毯子了吗？

After just 150 years,

仅仅150年，

we have a dense carpet of forest.

就形成了如此致密的树林。

But there's more.

不仅如此，

Because trees are growing so close together,

因为树木是紧挨着生长起来的，

and because tree species, tree sizes and ages

而且在很大的一片区域内，

are so similar across large areas,

树木的种类、尺寸和年龄都很相似，

fires not only move easily from acre to acre,

不仅导致火灾很容易蔓延，

but now, so do diseases and insect outbreaks,

而且一旦有疾病或者病虫害爆发，

which are killing or reducing the vitality

就会导致大片的森林

of really large sections of forest now.

死亡或者是生病。

And after a century without fire,

经历了没有火灾的1个世纪之后，

dead branches and downed trees on the forest floor,

林间铺满了枯枝和倒下的树木，

they're at powder-keg levels.

就像随时会爆炸的火药桶。

What's more, our summers are getting hotter

更严重的是， 如今的夏天是越来越热了，

and they're getting drier

也更加干燥，

and they're getting windier.

更加多风。

And the fire season is now 40 to 80 days longer each year.

每年的火灾季都会延长40-80天。

Because of this, climatologists are predicting

基于此，气候学家预测，

that the area burned since 2000

2000年以后发生过火灾的地区，

will double or triple

在未来30年

in the next three decades.

数量会增致2倍甚至3倍。

And we're building houses in the middle of this.

我们在森林中盖房子。

Two recently published studies tell us

最近公布的2项研究结果表明，

that more than 60 percent of all new housing starts are being built

有超过60%的新建房屋

是位于这些易燃的危险区域。

in this flammable and dangerous mess.

So when we do get a fire,

所以一旦着起火来，

large areas can literally go up in smoke.

会很快蔓延到大片的区域。

How do you feel now

那么在看了我最开始

about the forest image

展示的关于森林的照片

that I first showed you?

你们现在是什么感受？

It scares the heck out of me.

反正我是被吓坏了。

So what do we do?

那我们应该怎么做？

We need to restore the power of the patchwork.

我们要重新发挥区块的作用。

We need to put the right kind of fire

要把程度合适的火灾

back into the system again.

重新引入到整个系统中间。

It's how we can resize the severity of many of our future fires.

这样我们才能够控制 未来火灾的剧烈程度。

And the silver lining is that we have tools

值得庆幸的是我们有工具，

and we have know-how to do this.

我们也很清楚应该怎么做。

Let's look at some of the tools.

我们来看看其中一些工具。

We can use prescribed burning to intentionally thin out trees

我们可以安排有计划的焚烧， 来有意地减少树木

and burn up dead fuels.

烧掉枯枝败叶。

We do this to systematically reduce them and keep them reduced.

我们这么做是为了有计划 并持续地减少枯枝。

And what is that going to do?

这么做有什么好处呢？

It's going to create already-burned patches on the landscape

它能在森林中创造出 已经燃烧过的区块，

that will resist the flow of future fires.

能够阻止未来火灾的蔓延。

We can combine mechanical thinning with some of these treatments

我们可以将机械砍伐 跟上述方式相结合，

where it's appropriate to do so,

在合适的地方这么来操作，

and capture some commercial value

还能获取一些商业价值，

and perhaps underwrite some of these treatments,

也许能将这些方式外包出去，

especially around urban areas.

尤其是在城市周边地区。

And the best news of all is that prescribed burning produces

有计划焚烧最大的好处就是

so much less smoke than wildfires do.

它产生的烟比森林大火少多了。

It's not even close.

根本没法比。

But there's a hitch:

但是有一点，

prescribed burning smoke is currently regulated under air quality rules

有计划焚烧产生的烟 受空气质量法规管制，

as an avoidable nuisance.

是“可以避免的不当行为”。

But wildfire smoke?

但是森林大火的烟呢？

It simply gets a pass.

就没人管了。

Makes sense, doesn't it? (Laughs)

是这个道理，对吧？ （笑声）

So you know what happens?

结果怎么样？

我们的有计划焚烧进行得非常少，

We do far too little prescribed burning,

and we continually eat smoke in the summers

而我们在夏季要吸入大量

from megafires.

森林大火产生的浓烟。

We all need to work together to get this changed.

我们要共同行动，做出改变。

And finally, there's managed wildfires.

最后，还有可控的森林大火。

Instead of putting all the fires out,

我们不必将所有火灾都扑灭，

we need to put some of them back to work

而要善加利用，

thinning forests and reducing dead fuels.

降低森林密度，清除枯枝败叶。

We can herd them around the landscape

我们要在森林中合适的地方

when it's appropriate to do so

让火灾发生，

to help restore the power of the patchwork.

重新发挥区块的作用。

And as you've probably figured out by now,

到现在大家可能已经意识到了，

this is actually a social problem.

这其实是一个社会问题。

It's got ecological and climate explanations,

它跟生态和气候有关，

but it's a social problem, and it will take us humans to solve it.

但其实是一个社会问题， 需要我们人类来解决它。

Public support for these tools is poor.

对于刚刚提到的工具， 公共支持还不够。

Prescribed burning and managed wildfires are not well-supported.

对于有计划的焚烧和 受控制的森林大火支持还不够。

We actually all simply want fires to magically go away

我们都简单的希望， 火灾和它讨厌的浓烟一起

and take that pesky smoke with them, don't we?

神奇地消失，不是吗？

But there is no future without lots of fire and lots of smoke.

然而未来不可能没有火灾和浓烟。

That option is actually not on the table.

这是不可能完全避免的。

Until we, the owners of public lands, make it our high priority

直到我们——公共土地的拥有者们——

to do something about the current situation,

行动起来，努力改变现状，

we're going to experience continued losses to megafires.

我们还会经历许多次 带来巨大损失的火灾。

So it's up to us.

一切取决于我们。

We can spread this message to our lawmakers,

我们可以让立法者明白这一点，

folks who can help us manage our fires

让他们帮助我们管理火灾，

and our forests.

管理森林。

If we're unsuccessful,

如果我们失败的话，

where will you go to play

我们喜欢的地方都被烧毁了，

when your favorite places are burned black?

那我们还能去哪儿玩呢？

Where will you go

我们去哪儿

to breathe deep

尽情地

and slow?

深呼吸呢？

Thank you.

谢谢大家。

(Applause)

（掌声）