One of the consequences of a warming world is that high mountain habitats， which used to be too chilly for trees， are heating up。 "There is now newly available real estate above what we call tree line—the sort of literal line in the sand above which trees can’t grow because it’s too cold。 But now it’s not。"

　　全球變暖的其中一個后果是，對樹木來說曾經過于寒冷的高山環境正在逐漸升溫。“現在，在我們稱為“林木線”的上方出現了新的可用生長空間——這種線類似于分界線，由于過于寒冷，樹木在該線之上無法生長。但是，現在情況已經改變。”

　　Brian Smithers is an ecologist at U。C。 Davis。 He compares this slow—moving migration to land—grabs back in pioneer times。 "You know， they fired the guns and all the settlers made a mad dash to claim their stake。 It’s that， but if everybody were crawling on their bellies or something like that instead。"

　　布萊恩史密瑟斯是加州大學戴維斯分校的生態學家。他將這種緩慢遷移與開拓時期的土地掠奪進行了比較。“你知道，他們開了火，當時所有開拓者都在瘋狂地占領地盤。事實就是這樣，但是如果所有人都匍匐前進，或是替換成會爬的東西會怎么樣？”

　　Smithers is studying this upslope race among bristlecone pines。 These trees can live for more than 5，000 years—making them the oldest individual organisms on Earth。 Many of them eke out a living in dry， rocky soils， on windblown ridgelines around 11，000 feet， in eastern California and Nevada。 "They look like the worst bonsai tree imaginable。 They just look gnarled and twisted， something that looks like it’s taken a beating for 5，000 years and still living。"

　　史密瑟斯正在研究狐尾松之間的上升競賽。這些樹的壽命可超過5000年，這使它們成為地球上最古老的生物個體。在加州東部和內華達州干燥的石質土以及約1。1萬英尺高的風蝕山脊線上，許多狐尾松在勉強度日。“它們看起來像是你能想得到的最糟糕的盆景樹。這些樹有很多節瘤，而且形狀扭曲，看上去像過去5000年一直在挨打，但依然存活著。”