?Forests with numerous tree species, and therefore a mix of water-management strategies, appear more tolerant of drought.在森林里種植多樣樹種,并因此使用混合的水管理策略,這樣能使森林更耐干旱。
? 撰文\播音:克里斯托弗·因塔利亞塔(Christopher Intagliata) 翻譯:陳美娟 審校:郭曉
? You've probably heard the financial advice that?a diversified portfolio is better in turbulent times? Well that same wisdom may hold true for our stocks of trees. Because ecologists say forests with?a diversity of trees?are better at weathering drought. The reason:? 你可能聽說過這樣的理財建議:在動蕩時期,多元投資組合是更好的選擇。這種智慧同樣適用于樹木儲備。因為生態(tài)學(xué)家說,樹種多元的森林能夠更好地抵御干旱。原因是: "There's a huge difference and a huge diversity of water transport strategies in trees." William Anderegg is an ecologist at the University of Utah. "It's everything from having deeper roots or shallower roots, to having these pipes that are incredibly well armored to withstand drought or incredibly weak in the face of drought." “不同樹種運(yùn)輸水分的策略天差地別。”猶他大學(xué)的生態(tài)學(xué)家威廉·安德艾格如是說。“有的樹根深植、有的扎根表面,有的全副武裝以抵抗干旱、有的則在干旱面前不堪一擊。” Anderegg and his team studied droughts in 40 forests around the world. And the forests with diverse tree populations, with a mix of water-management strategies, did better than forests made up of just one or a few species. Could be a couple reasons for that. 安德艾格和他的團(tuán)隊研究了全球40片森林里的干旱現(xiàn)象。擁有多樹種和不同水分管理策略的森林,比那些單一樹種或者少樹種的森林能更好地應(yīng)對(干旱)。這可能有兩個原因。 "One is that there are other forces that are acting on the ecosystem at the same time. Other stressors like insect attack, or other things they're competing for, competing for light and for nutrients, and this is why a more diverse forest is going to be more functional. It'll be more resilient to drought but maybe also have higher carbon uptake rates over the long term."? “其中一個原因是,在干旱時,生態(tài)系統(tǒng)中有其他外因同時發(fā)揮作用。其它刺激源包括昆蟲攻擊或者樹木競爭的光照、營養(yǎng)等,這就是為什么樹種多元的森林功能性更強(qiáng)的原因。這樣的森林干旱過后的復(fù)原性更高,但同時長期的碳吸收率也可能更高。” The second possibility, he says, is that a monoculture of drought-ready trees may?look?really resilient to drought. "Up until the drought is severe enough that a whole bunch of the trees shut down or even die. That threshold cliff response you would get in a one species forest and you may not get in a diverse forest." The full report is in the journal?Nature. [William R. L. Anderegg et al.,?Hydraulic diversity of forests regulates ecosystem resilience during drought] 他說,第二個可能的原因是,單一栽培耐旱樹種,森林在旱后可能復(fù)原力很強(qiáng)。“但干旱要是嚴(yán)重到讓一片樹木停止生長或者死亡,這種強(qiáng)復(fù)原力也就到頭了。這種單樹種閾值懸崖反應(yīng)或許不會出現(xiàn)在樹種多元的森林中。”完整的研究報告發(fā)表在《自然》雜志上。 The lesson for land managers, he says, is that forest restoration efforts following wildfires and disease outbreaks might want to focus on planting a diverse portfolio of tree species. So that even if water plummets, tree stocks will, hopefully, remain stable. 他說,土地管理者可從中得到的經(jīng)驗是,在森林野火和樹木疾病爆發(fā)之后的森林重建工作應(yīng)當(dāng)注重多樹種組合的種植。這樣即使水資源驟減,樹木量也許還有希望維持穩(wěn)定。