日前科学家们在瑞典发现了目前已知的世界上年龄最古老的树木，这株云杉在冰河时期过后不久就开始扎根，至今已经存活了将近1万年。
由瑞典于默奥大学的库尔曼教授带领的一个科研小组在瑞典中部地区发现了20株左右的云杉，树龄都在8000岁以上，其中一棵云杉，经科学家们利用碳测定法判断，至今已经拥有9550岁的“高龄”，令人惊讶的是至今它的生命力依然很顽强。
在此之前人们一直认为现存最古老的树是在北美发现的距今有4000至5000年历史的松树。根据吉尼斯世界纪录大全记载，此前世界上已知的年龄最老的树木为生长在美国加利福尼亚州白山的一株狐尾松，至今已经生活了4768年。
据库尔曼教授介绍，云杉这种植物对于气候变化十分敏感，而且很长一段时间以来人们都认为它们在瑞典当地属于“外来物种”，而这项重大发现则改变了人们的这种观点。库尔曼教授推测，有可能是早期居住在当地的人类在冰川消退后不久将这种植物移植过去的，而这棵云杉之所以能够生存这么久，原因可能有以下几点：寒冷与干燥的气候、森林大火非常罕见以及并不频繁的人类活动。
这棵云杉的树龄达9550年，打破先前北美地区所发现5000年老松树的纪录，同时改写北欧地区气候史。
这项研究发现的一个重要意义是，过去科学家认为9000多年前北欧地区处在冰河时期，但云杉树的存在显示当时的气候颇温暖，甚至比现在更暖和。
这棵树高度超过2米，树干直径大约20厘米，生长在海拔950米的地方。发现这棵树后不久，科学家就把树木标本送到位于美国佛罗里达州迈阿密的一家实验室检验。
ScienceDaily (Apr. 16, 2008) — The world's oldest recorded tree is a 9,550 year old spruce in the Dalarna province of Sweden. The spruce tree has shown to be a tenacious survivor that has endured by growing between erect trees and smaller bushes in pace with the dramatic climate changes over time.
This 9,550 year old spruce has been discovered in Dalarna, Sweden. A favourable climate has produced an upright trunk since the beginning of the 1940s. (Credit: Leif Kullman)
For many years the spruce tree has been regarded as a relative newcomer in the Swedish mountain region. "Our results have shown the complete opposite, that the spruce is one of the oldest known trees in the mountain range," says Leif Kullman, Professor of Physical Geography at Ume? University.
A fascinating discovery was made under the crown of a spruce in Fulu Mountain in Dalarna. Scientists found four "generations" of spruce remains in the form of cones and wood produced from the highest grounds.
The discovery showed trees of 375, 5,660, 9,000 and 9,550 years old and everything displayed clear signs that they have the same genetic makeup as the trees above them. Since spruce trees can multiply with root penetrating braches, they can produce exact copies, or clones.
The tree now growing above the finding place and the wood pieces dating 9,550 years have the same genetic material. The actual has been tested by carbon-14 dating at a laboratory in Miami, Florida, USA.
Previously, pine trees in North America have been cited as the oldest at 4,000 to 5,000 years old.
In the Swedish mountains, from Lapland in the North to Dalarna in the South, scientists have found a cluster of around 20 spruces that are over 8,000 years old.
Although summers have been colder over the past 10,000 years, these trees have survived harsh weather conditions due to their ability to push out another trunk as the other one died. "The average increase in temperature during the summers over the past hundred years has risen one degree in the mountain areas," explains Leif Kullman.
Therefore, we can now see that these spruces have begun to straighten themselves out. There is also evidence that spruces are the species that can best give us insight about climate change.
The ability of spruces to survive harsh conditions also presents other questions for researchers.
Have the spruces actually migrated here during the Ice Age as seeds from the east 1,000 kilometres over the inland ice that that then covered Scandinavia? Do they really originate from the east, as taught in schools? "My research indicates that spruces have spent winters in places west or southwest of Norway where the climate was not as harsh in order to later quickly spread northerly along the ice-free coastal strip," says Leif Kullman.
"In some way they have also successfully found their way to the Swedish mountains."
The study has been carried out in cooperation with the County Administrative Boards in J?mtland and Dalarna.
