As you've probably noticed, in recent years, a lot of western forests have burned in large and destructive wildfires. If you're like me -- this western landscape is actually why my family and I live here. And as a scientist and a father, I've become deeply concerned about what we're leaving behind for our kids, and now my five grandkids.
大家可能注意到了, 近几年,西部很多森林爆发了 大规模毁灭性的火灾。 你们可能跟我一样, 西部的森林正是吸引我和我的家人 生活在那里的原因。 作为一名科学家,一名父亲, 我为我们留给子孙后代的东西 感到深深的担忧, 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 in just the last 10 years, and tens of thousands of homes have been destroyed. Acres burned and homes destroyed have steadily increased over the last three decades, and individual fires that are bigger than 100,000 acres -- they're actually on the rise. These are what we call "megafires." Megafires are the result of the way we've managed this western landscape over the last 150 years in a steadily warming climate. Much of the destruction that we are currently seeing could actually have been avoided.
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 被火灾烧毁, 数万的房屋被毁。 火灾面积和被毁房屋数量 在过去30年间 一直在持续增长, 着火面积超过405平方公里的 单场火灾数量 也在增长。 我们称之为“大型火灾”。 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 所导致的后果。 很多我们如今看到的灾难 本来是可以避免的。
I've spent my entire career studying these western landscapes, and the science is pretty clear: if we don't change a few of our fire-management habits, we're going to lose many more of our beloved forests. Some won't recover in our lifetime or my kids' lifetime. It's time we confront some tough truths about wildfires, and come to understand that we need to learn to better live with them and change how they come to our forests, our homes and our communities.
我整个职业生涯 都在研究西部的森林, 其中的科学道理其实很简单: 如果我们不改变一些防火习惯, 我们还将失去更多珍爱的森林。 其中一些可能在我们这一代, 甚至是下一代都无法恢复。 我们要面对森林火灾的 几个残酷事实, 要明白,我们需要学会适应它, 如何改变它来临的方式, 无论是对森林, 对我们的家, 还是对我们的社区。
So why is this happening? Well, that's what I want to talk to you about today. You see this forest? Isn't it beautiful? Well, the forests that we see today look nothing like the forests of 100 or 150 years ago. Thankfully, panoramic photos were taken in the 1930s from thousands of western mountaintop lookouts, and they show a fair approximation of the forest that we inherited. The best word to describe these forests of old is "patchy." The historical forest landscape was this constantly evolving patchwork of open and closed canopy forests of all ages, and there was so much evidence of fire. And most fires were pretty small by today's standards. And it's important to understand that this landscape was open, with meadows and open canopy forests, and it was the grasses of the meadows and in the grassy understories of the open forest that many of the wildfires were carried.
那么森林火灾是怎么发生的呢? 这正是我今天要讲的。 看到这片森林了吗? 真是漂亮极了。 我们今天看到的森林 与100到150年前的 森林完全不同。 幸亏在30年代, 数以千计的西部山区防火员 拍下了许多全景照片, 能让我们一窥所继承的森林的 大致情况。 形容这些森林最好的一个词 就是“参差不齐”。 历史上的森林景观 就是这种不断发展的块状区域, 里面是各个时期的森林,疏密相间, 有许多火灾的痕迹。 如果按今天的标准来看, 大部分火灾都很小。 很重要的一点, 这些森林间是有空隙的, 中间有草地,树林疏密相间, 是这些林间草地 和位于树林间的落叶层 承受了大部分的火灾。
There were other forces at work, too, shaping this historical patchwork: for example, topography, whether a place faces north or south or it's on a ridge top or in a valley bottom; elevation, how far up the mountain it is; and weather, whether a place gets a lot of snow and rain, sunlight and warmth. These things all worked together to shape the way the forest grew.
还有其他的力量 也对造成这种块状区域起了作用: 比如地形,是朝南还是朝北, 是在山脊还是在谷底, 还有海拔,也就是山的高度, 还有天气,是否有大量雨雪, 日照和气温。 这些因素共同作用 决定了森林生长的方式。
And the way the forest grew shaped the way fire behaved on the landscape. There was crosstalk between the patterns and the processes. You can see the new dry forest. Trees were open grown and fairly far apart. Fires were frequent here, and when they occurred, they weren't that severe, while further up the mountain, in the moist and the cold forests, trees were more densely grown and fires were less frequent, but when they occurred, they were quite a bit more severe. These different forest types, the environments that they grew in and fire severity -- they all worked together to shape this historical patchwork. And there was so much power in this patchwork. It provided a natural mechanism to resist the spread of future fires across the landscape. Once a patch of forest burned, it helped to prevent the flow of fire across the landscape. A way to think about it is, the burned patches helped the rest of the forest to be forest.
而森林生长的方式 又决定了火灾 如何对地貌产生影响。 模式和过程互相交织,相互干扰。 大家看新的干燥森林。 树是开放生长的, 树之间的空隙比较大。 火灾在这个区域经常发生, 但并不会很严重, 再往山上走, 在潮湿和寒冷的森林里, 树木生长密集,火灾频率不高, 但是一旦发生,就会更加严重。 森林的种类不同,生长环境不同, 还有火灾的严重程度, 这些因素交织在一起, 共同形成了历史区块。 这种区块的作用 非常强大。 它是一种天然的防御机制 防止未来的火灾蔓延到整个森林。 一旦某一个区块的森林着火了, 它能防止火灾蔓延到别的区块。 换句话说, 着火的区块拯救了剩下的森林, 让它们得以延续。
Let's add humans to the mix. For 10,000 years, Native Americans lived on this landscape, and they intentionally burned it -- a lot. They used fire to burn meadows and to thin certain forests so they could grow more food. They used fire to increase graze for the deer and the elk and the bison that they hunted. And most importantly, they figured out if they burned in the spring and the fall, they could avoid the out-of-control fires of summer.
让我们加入人类的影响。 1万年来,美洲原住民生活在这里, 他们焚烧了大片森林。 他们焚烧草地,把森林变得稀疏, 这样可以种更多粮食。 他们增加牧草, 用来喂养捕猎来的鹿、麋鹿和野牛。 最重要的是,他们发现, 如果他们在春季和秋季焚烧的话, 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, and by the 1880s, livestock grazing was in high gear. I mean, if you think about it, the cattle and the sheep ate the grasses which had been the conveyer belt for the historical fires, and this prevented once-frequent fires from thinning out trees and burning up dead wood. Later came roads and railroads, and they acted as potent firebreaks, interrupting further the flow of fire across this landscape.
欧洲移民——这已经是 很久以后的事儿了,在19世纪中叶, 在19世纪80年代, 畜牧业发展很快, 想象一下,牛羊吃掉的草 是历史上那些火灾的传送带, 它们阻止了日渐稀薄的森林中 曾经频发的火灾, 并且清除死掉的树木。 然后公路和铁路出现了, 它们是有效的防火道, 能防止火灾蔓延到整片森林。
And then something happened which caused a sudden pivot in our society. In 1910, we had a huge wildfire. It was the size of the state of Connecticut. We called it "the Big Burn." It stretched from eastern Washington to western Montana, and it burned, in a few days, three million acres, devoured several towns, and it killed 87 people. Most of them were firefighters.
之后发生了一件事情, 彻底改变了我们的社会。 1910年,发生了一场巨大的火灾。 着火面积有康涅狄格州那么大。 我们称之为“大火灾”。 它从华盛顿东部一直蔓延到 蒙大拿州西部, 在短短几天内, 它烧毁了约12000平方公里的土地, 毁掉了许多村庄,有87人丧生。 大部分是消防员。
Because of the Big Burn, wildfire became public enemy number one, and this would shape the way that we would think about wildfire in our society for the next hundred years. Thereafter, the Forest Service, just five years young at the time, was tasked with the responsibility of putting out all wildfires on 193 million acres of public lands, and they took this responsibility very seriously. They developed this unequaled ability to put fires out, and they put out 95 to 98 percent of all fires every single year in the US. And from this point on, it was now fire suppression and not wildfires that would become a prime shaper of our forests.
因为这场大火灾,森林火灾成为了 公众的头号敌人, 这件事改变了我们整个社会 在接下来100年里 对于森林大火的看法。 之后,刚刚成立5年的 国家森林局, 承担起了在78万 平方公里的公共土地上 扑灭火灾的责任, 他们将这项责任 看得很重。 他们发展出了灭火的超级能力, 扑灭了每年发生在美国的 火灾中的95%-98%。 从那时开始,森林的主要塑形者 就不再是森林大火, 而是对森林大火的压制。
After World War II, timber harvesting got going in the west, and the logging removed the large and the old trees. These were survivors of centuries of wildfires. And the forest filled in. Thin-barked, fire-sensitive small trees filled in the gaps, and our forests became dense, with trees so layered and close together that they were touching each other.
二战过后,伐木业开始进入西部, 砍伐掉了许多巨大而古老的树木。 它们是几个世纪以来 森林大火的幸存者。 新的森林补充进来。 是那些树皮很薄,容易着火的小树, 我们的森林变得浓密, 层层叠叠,距离很近, 互相紧挨着。
So fires were unintentionally blocked by roads and railroads, the cattle and sheep ate the grass, then along comes fire suppression and logging, removing the big trees, and you know what happened? All these factors worked together to allow the forest to fill in, creating what I call the current epidemic of trees.
于是大火无意中 被公路和铁路阻断, 牛羊吃光了林间的草地, 对火灾的压制 以及被伐木业移除的大树, 结果怎么样? 所有这些因素叠加在一起 让新的森林补充进来, 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, the change is actually remarkable. Notice how the patchwork has filled in. Dry south slopes -- they're now covered with trees. A patchwork that was once sculptured by mostly small and sort of medium-sized fires has filled in. Do you see the blanket of trees? After just 150 years, we have a dense carpet of forest.
所以比较一下100年前 和现在的森林, 变化还是很大的。 看这些区块是如何形成的。 南边干燥的斜坡, 现在已经长满了树。 这些区块曾经是因为小型 或者中型的火灾形成的, 如今已经长满了树。 看到这一层由树木组成的毯子了吗? 仅仅150年, 就形成了如此致密的树林。
But there's more. Because trees are growing so close together, and because tree species, tree sizes and ages are so similar across large areas, fires not only move easily from acre to acre, but now, so do diseases and insect outbreaks, which are killing or reducing the vitality of really large sections of forest now. And after a century without fire, dead branches and downed trees on the forest floor, they're at powder-keg levels.
不仅如此, 因为树木是紧挨着生长起来的, 而且在很大的一片区域内, 树木的种类、尺寸和年龄都很相似, 不仅导致火灾很容易蔓延, 而且一旦有疾病或者病虫害爆发, 就会导致大片的森林 死亡或者是生病。 经历了没有火灾的1个世纪之后, 林间铺满了枯枝和倒下的树木, 就像随时会爆炸的火药桶。
What's more, our summers are getting hotter and they're getting drier and they're getting windier. And the fire season is now 40 to 80 days longer each year. Because of this, climatologists are predicting that the area burned since 2000 will double or triple in the next three decades.
更严重的是, 如今的夏天是越来越热了, 也更加干燥, 更加多风。 每年的火灾季都会延长40-80天。 基于此,气候学家预测, 2000年以后发生过火灾的地区, 在未来30年 数量会增致2倍甚至3倍。
And we're building houses in the middle of this. Two recently published studies tell us that more than 60 percent of all new housing starts are being built in this flammable and dangerous mess. So when we do get a fire, large areas can literally go up in smoke.
我们在森林中盖房子。 最近公布的2项研究结果表明, 有超过60%的新建房屋 是位于这些易燃的危险区域。 所以一旦着起火来, 会很快蔓延到大片的区域。
How do you feel now about the forest image that I first showed you? It scares the heck out of me.
那么在看了我最开始 展示的关于森林的照片 你们现在是什么感受? 反正我是被吓坏了。
So what do we do? We need to restore the power of the patchwork. We need to put the right kind of fire back into the system again. It's how we can resize the severity of many of our future fires. And the silver lining is that we have tools and we have know-how to do this.
那我们应该怎么做? 我们要重新发挥区块的作用。 要把程度合适的火灾 重新引入到整个系统中间。 这样我们才能够控制 未来火灾的剧烈程度。 值得庆幸的是我们有工具, 我们也很清楚应该怎么做。
Let's look at some of the tools. We can use prescribed burning to intentionally thin out trees and burn up dead fuels. We do this to systematically reduce them and keep them reduced. And what is that going to do? It's going to create already-burned patches on the landscape that will resist the flow of future fires. We can combine mechanical thinning with some of these treatments where it's appropriate to do so, and capture some commercial value and perhaps underwrite some of these treatments, especially around urban areas. And the best news of all is that prescribed burning produces so much less smoke than wildfires do. It's not even close.
我们来看看其中一些工具。 我们可以安排有计划的焚烧, 来有意地减少树木 烧掉枯枝败叶。 我们这么做是为了有计划 并持续地减少枯枝。 这么做有什么好处呢? 它能在森林中创造出 已经燃烧过的区块, 能够阻止未来火灾的蔓延。 我们可以将机械砍伐 跟上述方式相结合, 在合适的地方这么来操作, 还能获取一些商业价值, 也许能将这些方式外包出去, 尤其是在城市周边地区。 有计划焚烧最大的好处就是 它产生的烟比森林大火少多了。 根本没法比。
But there's a hitch: prescribed burning smoke is currently regulated under air quality rules as an avoidable nuisance. But wildfire smoke? It simply gets a pass. Makes sense, doesn't it? (Laughs) So you know what happens? We do far too little prescribed burning, and we continually eat smoke in the summers from megafires. We all need to work together to get this changed.
但是有一点, 有计划焚烧产生的烟 受空气质量法规管制, 是“可以避免的不当行为”。 但是森林大火的烟呢? 就没人管了。 是这个道理,对吧? (笑声) 结果怎么样? 我们的有计划焚烧进行得非常少, 而我们在夏季要吸入大量 森林大火产生的浓烟。 我们要共同行动,做出改变。
And finally, there's managed wildfires. Instead of putting all the fires out, we need to put some of them back to work thinning forests and reducing dead fuels. We can herd them around the landscape when it's appropriate to do so to help restore the power of the patchwork.
最后,还有可控的森林大火。 我们不必将所有火灾都扑灭, 而要善加利用, 降低森林密度,清除枯枝败叶。 我们要在森林中合适的地方 让火灾发生, 重新发挥区块的作用。
And as you've probably figured out by now, this is actually a social problem. It's got ecological and climate explanations, but it's a social problem, and it will take us humans to solve it. Public support for these tools is poor. Prescribed burning and managed wildfires are not well-supported. We actually all simply want fires to magically go away and take that pesky smoke with them, don't we? But there is no future without lots of fire and lots of smoke. That option is actually not on the table. Until we, the owners of public lands, make it our high priority to do something about the current situation, we're going to experience continued losses to megafires.
到现在大家可能已经意识到了, 这其实是一个社会问题。 它跟生态和气候有关, 但其实是一个社会问题, 需要我们人类来解决它。 对于刚刚提到的工具, 公共支持还不够。 对于有计划的焚烧和 受控制的森林大火支持还不够。 我们都简单的希望, 火灾和它讨厌的浓烟一起 神奇地消失,不是吗? 然而未来不可能没有火灾和浓烟。 这是不可能完全避免的。 直到我们——公共土地的拥有者们—— 行动起来,努力改变现状, 我们还会经历许多次 带来巨大损失的火灾。
So it's up to us. We can spread this message to our lawmakers, folks who can help us manage our fires and our forests. If we're unsuccessful, where will you go to play when your favorite places are burned black? Where will you go to breathe deep and slow?
一切取决于我们。 我们可以让立法者明白这一点, 让他们帮助我们管理火灾, 管理森林。 如果我们失败的话, 我们喜欢的地方都被烧毁了, 那我们还能去哪儿玩呢? 我们去哪儿 尽情地 深呼吸呢?
Thank you.
谢谢大家。
(Applause)
(掌声)