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.
你們可能已經注意到, 近年來,有很多西部的森林 遭到毀滅性的大型野火摧殘。 如果你們和我一樣, 像這樣的西部風景,就是我和 我的家人會住在這裡的原因。 身為科學家和父親, 我非常關切我們會留下什麼給 我們的孩子,和我現在的五個孫子。
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.
在美國,僅在過去十年間, 被火燒毀的面積就比奧勒崗州還大, 數萬個家園因此被摧毀。 過去三十年間,被燒毀的土地面積 和被摧毀的家園數目 一直穩定在增加, 而面積大於十萬英畝的個別火災數目 事實上是在增加的。 我們稱這些大火為「超級大火」。 超級大火發生的原因, 是我們過去 150 年來, 在穩定持續暖化的氣候下, 經營這塊西部地景的方式。 我們目前看到的破壞, 其實大多數是本來可以避免的。
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.
我的整個職涯都在 研究這些西部地景, 科學是非常明確的: 如果不改變我們 管理大火的一些習慣, 我們將會失去更多更多鍾愛的森林。 有些是在我們一生中, 甚至我們孩子的一生中, 都無法復元的。 該是時候了,該來面對 關於野火的棘手真相了, 要了解,我們必須學習 和它們共處得更好一些, 並改變它們如何來到我們的森林、 我們的家園、 我們的社區。
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.
所以,為什麼會發生? 這就是今天我想和大家談的。 看到這座森林了嗎? 它很美,不是嗎? 我們現今看到的森林, 一點也不像 100 或 150 年前的森林。 謝天謝地,1930 年代時, 自西部山頂瞭望所 拍攝了數千個全景照片, 靠這些照片,我們可以大略呈現出 我們所繼承的森林的樣貌。 要形容這些老森林, 最好的詞就是「拼湊成的」。 歷史的森林地景, 是不斷演化的拼湊之作, 由各種年齡,稀疏與鬱閉的 冠層森林拼湊而成, 有好多大火燒過的痕跡。 用現今的標準來看, 大部份的火災規模都算很小。 重要的是要了解這是個稀疏的地景, 有草地,也有稀疏冠層森林; 是草地上的草, 以及稀疏森林中長滿草的林下層, 被許多野火燒了過去。
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.
還有其他的力量 形成這個歷史上的拼湊物, 比如:地形學,地形朝南或朝北, 是在山脊上或是在谷底; 海拔高度,在山上多高的地方; 是否常常下雪或是下雨, 是否有陽光且溫暖。 所有這些元素加在一起, 造成森林成長的方式。
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.
而森林成長的方式, 就會形成大火在地景上的行為方式。 在模式和過程之間互相干擾影響。 如你所見,左側是新的乾燥森林。 樹木開放成長,且間距算是遠的。 大火常常在這裡發生, 發生時都不會太嚴重, 再往山上一點, 中間是潮濕且寒冷的森林, 樹木的密度比較高, 比較不常發生大火, 但一旦發生大火, 通常會比較嚴重一些。 不同類型的森林、它們的生長環境, 以及大火的猛烈程度, 通通作用在一起, 形成了這個歷史的拼湊之作。 在這個拼湊之作當中, 有著非常大的力量。 它提供了一個自然機制, 來抵抗未來的大火, 不讓它們在地景上擴散。 一旦森林其中一塊被燒掉, 它能協助防止大火延燒至地景各處。 可以把它看待成, 森林中被燒毀的那些部份, 能協助維持剩下的森林仍然是森林。
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.
讓我們混合考量人類的因素。 美國原住民在這地景上住了一萬年, 他們常常會刻意放火, 用火燒草原,讓某些森林變得稀疏, 來種更多的食物。 他們用火來增加牧草的量, 供獵獲的鹿、麋和野牛食用。 最重要的是 他們了解如果在春天和秋天放火, 就能避免夏天失控的大火。
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.
很久之後,歐洲人 於十九世紀中期開始殖民, 1880 年代到達家畜放牧的高點。 我的意思是,試想牛和羊要吃草, 這些草地曾是史上火災的輸送帶, 使得以前頻繁的大火 不再能夠稀疏樹木、燒光枯木。 然後出現了道路和鐵路, 它們成了非常有效的防火道, 進一步阻斷大火延燒至地景各處。
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.
接下來發生的事使社會突然轉變。 1910 年,有一場大野火, 大小和康乃迪克州一樣大。 我們稱之為「大火燒(Big Burn)」。 它的範圍從華盛頓州的東邊 一路延伸到蒙大拿州的西邊, 幾天之內就燒毀了三百萬英畝的地, 吞滅了數個小鎮, 造成 87 人死亡, 大部份是消防員。
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.
這次的大火燒使得野火 成了全民的頭號公敵, 塑造我們社會在接下來百年間 對於野火的看法。 其後,當時成立才五年的林務局 被賦予重任, 要消滅公地上所有的野火, 多達 193 百萬英畝的面積。 他們非常認真地看待這項責任, 發展出無與倫比的滅火能力, 每年 95% 至 98% 的全美國大火 被他們撲滅掉。 從此之後, 撲滅火災取代了野火, 成為我們森林成形的主要因素。
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.
二次世界大戰後, 西部開始伐木, 砍伐原木造成大樹和老樹消失。 它們原是百年來野火下的倖存者。 森林接著填補上來, 對火敏感的薄皮小樹木補滿了空隙, 我們的森林變成高密度, 樹木近近疊在一起,會彼此碰觸;
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.
道路和鐵路無意間阻斷火的蔓延; 牛和羊吃草; 接著而來的人為滅火、 伐木和砍掉大樹, 你們可知道發生了什麼事? 所有這些因素一起作用, 森林填補了間隙, 造成我稱為「目前樹木氾濫的疫情」。
(Laughter)
(笑聲)
Go figure.
去想想吧。
(Laughter)
(笑聲)
More trees than the landscape can support.
樹木的數量遠超過 地景能夠支持的量。
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.
因此,比較百年前和現今的森林, 改變其實很驚人。 注意看拼湊之作是怎麼被填補的。 原本乾燥的南面山坡 現在被樹木覆蓋滿了。 曾經主要由中小型的火災 所塑成的拼湊之作 已經被填補滿了。 看到樹木的覆蓋層了嗎? 僅僅經過 150 年, 已經有了一片高密度的森林。
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.
還不只如此。 因為樹木生長的距離非常近, 因為長在大片區域中的樹木, 種類、尺寸、年齡都太相似, 火勢不但很容易從 一英畝延燒到下一英畝, 發生的疾病和昆蟲疫情 也一樣容易傳播, 因此造成現在的森林 大片區域地死亡或衰弱。 一整個世紀沒有火災之後, 在森林地面上的枯枝和倒樹 處在一觸即發的層級。
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.
此外,夏天越來越熱, 越來越乾燥, 風也越來越大 。 如今每年的火季長了 40~80 天。 因此,氣候學家預測, 自 2000 年起燒掉區域的面積, 在接下來三十年間會 變為兩倍或三倍。
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.
而我們在這其中蓋房子。 兩份近期發佈的研究告訴我們, 超過 60% 的新住房 被建築在這種可燃且危險的地方。 所以一旦發生火災, 會有大片的面積化為灰燼。
How do you feel now about the forest image that I first showed you? It scares the heck out of me.
現在你們對於我一開始 讓各位看的那張森林圖片 感覺如何? 它把我嚇壞了。
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.
我們應該怎麼做? 我們得要恢復拼湊之作的力量。 我們得要把「對」的那種火 再次放回到系統當中。 這種方式能讓我們改變 許多未來火災的嚴重程度。 讓人感到欣慰的是 我們有工具, 也有該怎麼做的實際知識。
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.
咱們來看看其中一些工具。 我們可以用計畫性火燒(控制燒除) 來刻意讓樹木變稀疏, 並燒盡可燃物。 這麼做可以系統性地減少 並保持它們於少量。 那會有什麼結果? 那會在地景上創造出 已經燒光的區塊, 能夠防止未來大火的竄燒。 我們可以把機械式的稀疏做法 和這類處理方式結合, 在適當的情況下這麼做, 並獲得一些商業價值, 也許還能承保這類處理方式, 特別是在都市地區。 最好的消息是計畫性火燒所產生的煙 遠遠少於野火產生的煙。 差距很大。
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.
但有個問題: 依目前空氣品質規定的規範, 計畫性火燒的煙是可避免的妨礙行為。 但野火的煙呢? 它沒被規範。 合理嗎?(笑聲) 所以會發生什麼事? 我們計畫性的火燒做得太少了, 因而使我們在夏天 持續吸入來自超級大火的煙。 我們得要同心協力來改變這一點。
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.
最後,還有管制野火。 不要撲滅所有的野火, 得要讓其中一些繼續燒下去, 讓森林變稀疏,減少乾枯的可燃物。 我們可以在地景上「放牧」野火, 在適當的情況下這樣做, 就能協助恢復拼湊之作的力量。
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.
現在你們可能已經想通了, 這其實是個社會問題。 它的確有生態上和氣候上的解釋, 但它是個社會問題, 需要我們人類來解決。 沒有多少大眾支持這些工具。 計畫性火燒和管制野火 並沒有受到很好的支持。 事實上我們只想要大火 神奇地自己熄滅掉, 也一併帶走討厭的煙,對吧? 但未來不可能沒有 多場火災和很多的煙。 其實桌面上並沒有這選項。 直到公共土地的所有者 將這問題列為優先, 針對目前的情況行動, 不然我們就會繼續經歷 超級大火造成的損失。
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?
所以,決定權在我們的手上。 我們可以把這訊息傳給立法者, 給那些能夠協助我們 管制大火和森林的人。 如果我們沒能成功, 當你最喜歡的地方被燒到焦黑時, 你要到哪裡去玩? 你要去哪裡 緩慢地深呼吸?
Thank you.
謝謝。
(Applause)
(掌聲)