2013年4月26日 星期五

日本屋久島林樹死亡是否為中國污染肇禍的?

日本屋久島日誌

日本樹木死亡疑是中國污染所致

Kosuke Okahara for The New York Times
環境工程學家永淵修(右二)檢查位於屋久島四周的監測站,衡量空氣中臭氧和含硫排放物的水平。Osamu Nagafuchi, second right, an environmental engineer, checks a monitoring station around Yakushima to measure levels in the air of ozone and sulfur emissions, which are typically the byproducts of burned coal or automobile exhaust.

日本屋久島——這座島上的原始森林中出現了一場神秘的疫病,許多樹木死亡。現在,蒼白乾 枯的死樹殘枝散落在深綠色的山間。環境工程學家永淵修(Osamu Nagafuchi)對屋久島及這裡高低起伏的地貌充滿熱情。他認為疫病的幕後元兇是空氣污染物,來自幾百英里之外煙霧滾滾的中國。

多年來,永淵修的理論一直被其他科學家所忽視。而負責管理這座西南島嶼上的森林的中央政府官僚們,對他的觀點也大加嘲笑。然而,現在日本已經開始認 真對待他的警告。日本全國都對健康問題產生了恐慌,人們擔心,可能具有危險性的空氣污染顆粒物越來越多,而且它們已經席捲了日本的其他地區。現在許多人認 為其源頭是快速工業化的巨大鄰國——中國。

最近,中國已向公眾發佈了更多警告,指出中國城市裡濃灰的空氣,產生健康危害的風險越來越高,因此日本的恐慌達到了一個新高度。儘管永淵修和一小群 合作者表示,他們的研究並沒有政治動機,但他們也承認,對中國已經開始產生怨恨的公眾,可能更容易接受他們的觀點。公眾怨恨中國的原因有,中國取代日本成 為了亞洲最大的經濟體,而且他們認為,在針對雙方都聲稱擁有主權的島嶼產生的領土爭端中,中國的態度趾高氣揚。
日本官員仍然在質疑,這些松樹的死亡是否應歸咎於空氣中的污染物。但是,至少他們和其他科學家,已經開始把遠離日本國內工業中心的屋久島看做一個理想實驗室,用於了解中國日益加劇的環境問題對鄰國的影響。

一些島民已經接受了永淵修的觀點,他們擔心污染物會威脅他們的健康。
屋久島町長荒木耕治(Koji Araki)稱:“我們有種煤礦里的金絲雀的感覺了。屋久島正好處在中國的下風向,所以我們首當其衝。”

無論原因是什麼,屋久島上樹木的死亡都很令人擔憂。屋久島是座多山的小島,位於日本四座主島最南端的九州島以南。日本其他地區人口稠密,而這座小島 卻森林茂密,地面上覆蓋著苔蘚,一派罕見的原始自然風貌。人們擔心,日益嚴重的煙霧問題,會使徒步者及其他生態旅行者對屋久島望而卻步。屋久島上的1.4 萬名居民需要以旅遊業為生。
旅客來屋久島,多數是為了觀賞其壯美的雪松。目前,這場導致松樹死亡的神秘疫病尚未影響雪松。1993年,屋久島因其雪松被聯合國教科文組織(Unesco)列為世界遺產。
幾百年來,人們砍伐屋久島雪松,用於建造古都京都的一些宏偉廟宇。現存最大的雪松是繩文雪松(Jomon cedar)。此樹樹榦多瘤,底部周長16英尺(約合4.9米),估計至少有2600年樹齡。

正在死亡的樹木來自一個瀕危的松樹品種。這種松樹只見於屋久島及附近的一座島上。永淵修稱,1992年至1996年,當衛星照片顯示樹木死亡量大幅 增多時,他就注意到了這個問題。永淵修是日本中部滋賀縣立大學(University of Shiga Prefecture)的生態系統研究學教授。

1992年永淵修還是九州一座城市的公務員,當時他在屋久島的山頂徒步旅行時,就發現了變黑的雪。於是,他開始把收集和分析雪樣當做周末的愛好。讓 他驚訝的是,他發現雪樣中有硅、鋁和其他煤燃燒產生的副產品,中國人使用煤來為房屋供暖。利用風向圖判斷,他提出這些污染物是從中國跨過東海來到這裡的。

這個發現促使永淵修辭去了市裡的工作,並最終成為了一名大學教授,他的很多研究都是關於屋久島的。他在島上各處建立了小型的監測站,衡量空氣中臭氧的水平和含硫排放物的水平,這兩種物質通常是燃燒煤或汽車廢氣的副產品。

在最近某一天的下午,永淵修爬到了海拔約為2000米的黑味岳(Mt. Kuromi)頂端,來到了位於山頂的監測站,這是監測站中位置最高的一座。他連接上自己的筆記本電腦,從監測站的小型數字記錄器上下載數據,他指出,本 來應該清新純凈的空氣,現在籠罩着一層薄薄的霧霾。

今年62歲的永淵修每個月來一次屋久島,以收集數據。他說,“風從北京和天津刮過來時情況最糟糕。”這兩座中國城市位於西北方,距離此地900英里(約合1500公里)。“這就說明了,這樣一個大國工業化的時候,其影響會蔓延到各個地方。”

在20世紀90年代中期,最初發表這些研究發現時,永淵修和他的主要夥伴手塚賢至(Kenshi Tetsuka)首先受到了林業官員和資深科學家的嘲笑,這些科學家稱,他們是在聳人聽聞,目的是吸引公眾對樹木死亡的關注。一些科學家還質問,為什麼隨 着中國污染問題的加劇,樹木的死亡卻還是放緩了。永淵修說,相信污染很快地殺死了病弱的樹木,留下了更健壯的樹木。手塚賢至是一名島上的居民,他建立了一 個保護松樹的小型環保組織。

在2000年代早期,由於有證據顯示日本各地來自中國的污染物都出現增多,他的觀點開始得到接受。日本政府的林野廳(Forestry Agency)開始允許永淵修建立自己的監測站,而且正在與他和手塚賢至聯合開展研究。不過林野廳仍然認為死亡是昆蟲侵擾和鹿群規模失控造成的,後者可能 會吃光小松樹的松針。

他們指出,在中國經濟起飛之前,屋久島上就出現了松樹死亡情況。

林野廳駐屋久島的一位官員飯島弘治(Hiroharu Ijima,音譯)說:“我們不同意他的看法,但我們尊重他的研究。”

在北京污染物水平急劇提高,引人警覺之後,日本公眾對中國造成的環境影響所產生的焦慮,今年出現急劇惡化。此後,日本西部幾座城市的官員曾就高企的 PM2.5水平發出警告。PM2.5是指尺寸小於2.5微米的微小顆粒,這種顆粒小到足以沉積到人的肺部。數座日本城市今年發佈了警告,要求居民在污染物 水平急劇提高時待在室內。
上個月的一天,屋久島的空氣變得特別渾濁,當地官員請求借用永淵修的監測站來測量PM2.5水平。結果,當時的水平高於政府建議的安全水平,於是官員們要求當地的小學取消了一次到附近森林的戶外活動。

一些居民相信污染是由中國造成的。他們表示自己感到很無助,即使政府確信永淵修是對的,他們也懷疑政府沒辦法採取什麼措施。

“對於這件事,除了要求中國花費更多的錢凈化環境之外,我們能做的不多,”永淵修的研究助理手塚賢至說,“恐怕情況只會越來越糟。”
翻譯:王童鶴、梁英

Yakushima Journal

Trees Fall in a Japanese Forest, and a Scientist Is There to Blame China


YAKUSHIMA, Japan — A mysterious pestilence has befallen this island’s primeval forests, leaving behind the bleached, skeletal remains of dead trees that now dot the dark green mountainsides. Osamu Nagafuchi, an environmental engineer with a passion for the island and its rugged terrain, believes he knows the culprit: airborne pollutants from smog-belching China, hundreds of miles away.
For years, Mr. Nagafuchi’s theory was ignored by fellow scientists and even mocked by bureaucrats in the national government who administer the forests on this southwestern island. But Japan has begun taking his warnings more seriously, as the nation has been gripped by a national health scare over rising levels of potentially dangerous airborne particles that have swept into other parts of Japan and that many now believe were produced by China, its huge and rapidly industrializing neighbor.
These fears have reached a new level recently as China itself has issued more public warnings about the growing health risks from its cities’ gray, soupy air. While Mr. Nagafuchi and a small number of collaborators say their research is not politically motivated, they admit that they may be finding more receptivity among a public that already resents China for supplanting Japan as Asia’s largest economy, and for what is seen as its haughty attitude in a territorial dispute over islands both countries claim.
Japanese officials still dispute whether airborne pollutants are responsible for killing the pine trees. But they and other scientists have at least begun to view Yakushima, which is far from Japan’s own industrial centers, as a pristine laboratory for understanding how China’s growing environmental problems could be affecting its neighbors.
Many islanders are already believers, and they worry that the pollutants may be threatening their health.
“We are starting to feel like the canary in a coal mine,” said the island’s mayor, Koji Araki. “Our island is right downwind from China, so we get the brunt of it.”
Whatever the cause, the tree die-off is a worrisome turn for this small, mountainous island off Kyushu, the southernmost of Japan’s main islands, whose moss-carpeted forests provide a rare patch of primitive nature in an otherwise densely populated nation. There are fears here that a growing smog problem could scare off the hikers and other ecotourists upon whom many of the island’s 14,000 residents depend for their livelihoods.
Most visitors come to see Yakushima’s majestic cedar trees, which have so far been unaffected by the mysterious ailment killing the pines. The cedars won the island the distinction of a Unesco World Heritage site in 1993.
The cedars were logged for centuries to build some of the great Buddhist temples in the ancient capital, Kyoto. The biggest remaining tree, the gnarled Jomon cedar, measures 16 feet around at the base and is estimated to be at least 2,600 years old.
The dying trees are from an endangered species of pine that is found only on Yakushima and a neighboring island. Mr. Nagafuchi, a professor of ecosystem studies at the University of Shiga Prefecture in central Japan, said he noticed the problem when satellite photographs showed a large increase in the number of dead trees between 1992 and 1996.
Mr. Nagafuchi, then a public employee for a city in Kyushu, had already found blackened snow while hiking to Yakushima’s mountaintops in 1992. He started collecting and analyzing the snow as a sort of weekend hobby. To his surprise, he found it contained silicon, aluminum and other byproducts from the burning of coal, which is used to heat homes in China. Using maps of winds, he theorized that the pollutants were carried here from China, across the East China Sea.
The discovery drove Mr. Nagafuchi to quit his city job and eventually become a university professor, doing much of his research on Yakushima. He has set up small monitoring stations around the island to measure levels in the air of ozone and sulfur emissions, which are typically the byproducts of burned coal or automobile exhaust.
On a recent afternoon, Mr. Nagafuchi climbed to the highest of those stations, atop Mt. Kuromi, a windswept peak that rises 6,000 feet above the sea below. After hooking up his laptop to download data from the station’s small digital recorder, he pointed out the thin, gauzy haze that clouded what he said should have been pristine air.
“The worst is when winds blow from Beijing and Tianjin,” two Chinese cities about 900 miles to the northwest, said Mr. Nagafuchi, 62, who visits Yakushima once a month to collect the data readings. “This is proof that when such a big country industrializes, its effect will spread everywhere.”
When they first started publicizing the findings in the mid-1990s, Mr. Nagafuchi and his main partner, Kenshi Tetsuka, an islander who started a small environmental group to protect the pines, were at first derided by forestry officials and established scientists who said they were sensationalizing the die-off to get public attention. Some scientists questioned why the tree deaths slowed even as China’s pollution problems have grown. Mr. Nagafuchi says he believes the pollution quickly killed off the weak trees, leaving the hardier ones.
His ideas began to win limited acceptance in the early 2000s, amid evidence of a growing influx of Chinese pollutants across Japan. The national government’s Forestry Agency began to allow Mr. Nagafuchi to set up his monitoring stations, and is doing joint research with him and Mr. Tetsuka, though it still believes the deaths are caused by an infestation of bugs and a runaway population of deer, which can strip small trees of pine needles.
They point out that there had been die-offs of pine trees on Yakushima even before China’s economic takeoff.
“We don’t agree with him, but we respect his research,” said Hiroharu Ijima, a Forestry Agency official on Yakushima.
Public anxieties about environmental effects from China have soared this year, after Beijing recorded alarming increases in pollution levels. That was followed by officials in western Japan issuing warnings in their own cities of high levels of particulate matter measuring 2.5 micrometers or less, known as PM 2.5, that are small enough to become embedded in human lungs. Several Japanese cities have issued warnings this year for residents to stay indoors when the pollutant levels spike.
When the air grew particularly hazy on Yakushima one day last month, local officials asked if they could use one of Mr. Nagafuchi’s monitoring stations to measure PM 2.5. The level was above government-recommended safe levels, prompting officials to order a local elementary school to cancel a field trip to a nearby forest.
Residents who believe the pollution is caused by China described feeling helpless, saying they doubt there is any action their government can take even if it becomes convinced Mr. Nagafuchi is right.
“There is not much we can do about this, except ask the Chinese to spend more money on environmental cleanup,” said Mr. Tetsuka, Mr. Nagafuchi’s research assistant. “I’m afraid it will only get worse and worse.”

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