“Old Tjikko”的意思、由来-开放百科全书

Old Tjikko is a {{age nts|-7542|04|17}}-year-old Norway Spruce, located on Fulufjället Mountain of Dalarna province in Sweden. Old Tjikko originally gained fame as the "world's oldest tree."^[1] Old Tjikko is, however, a clonal tree that has regenerated new trunks, branches and roots over millennia rather than an individual tree of great age. Old Tjikko is recognized as the oldest living Picea abies and the third oldest known clonal tree.

The age of the tree was determined by carbon dating of genetically matched plant material collected from under the tree, as dendrochronology would cause damage. The trunk itself is estimated to be only a few hundred years old, but the plant has survived for much longer due to a process known as layering (when a branch comes in contact with the ground, it sprouts a new root), or vegetative cloning (when the trunk dies but the root system is still alive, it may sprout a new trunk).

Discovery and details

The root system of Old Tjikko is estimated to be {{age nts|-7542|04|17}} years old,^[1]^[2] making it the world's oldest known Norway spruce. It stands {{convert|5|m}} tall and is located on Fulufjället Mountain of Dalarna province in Sweden.^[3] For thousands of years, the tree appeared in a stunted shrub formation (also known as a krummholz formation) due to the harsh extremes of the environment in which it lives. During the warming of the 20th century, the tree sprouted into a normal tree formation. The man who discovered the tree, Leif Kullman (Professor of Physical Geography at Umeå University), attributed this growth spurt to global warming and gave the tree its nickname "Old Tjikko" after his late dog.^[3]

The tree has survived for so long due to vegetative cloning. The visible tree is relatively young, but it is part of an older root system that dates back thousands of years. The trunk of the tree may die and regrow multiple times, but the tree's root system remains intact and in turn sprouts another trunk. The trunk may only live for about 600 years, and when one trunk dies another eventually grows back in its place.^[4] Also, each winter, heavy snow may push the tree's low-lying branches to ground level, where they take root and survive to grow again the next year^[1] in a process known as layering. Layering occurs when a tree's branch comes in contact with the earth, and new roots sprout from the contact point. Other trees, such as coast redwoods and western redcedars are known to reproduce by layering.^[5] The tree's age was determined by carbon-14 dating of the root system, which found roots dating back to 375, 5,660, 9,000, and 9,550 years. Carbon dating is not accurate enough to pin down the exact year the tree sprouted from seed; but, given the estimated age, the tree is supposed to have sprouted around 7550 BC. For comparison, the invention of writing (and thus, the beginning of recorded history) did not occur until around 4000 BC. Researchers have found a cluster of around 20 spruce trees in the same area, all over 8,000 years old.^[6]^[7]

Trees much older than 10,000 years would be practically impossible in Sweden, because until around 11,000 years ago the area was in the grip of a world-wide ice age.^[4] Nature conservancy authorities considered putting a fence around the tree to protect it from possible vandals or trophy hunters.^[8]

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References

1. ^¹²{{cite news |url=http://news.bbc.co.uk/2/hi/europe/7353357.stm |title=Swedes find 'world's oldest tree' |date=17 April 2008 |accessdate=6 May 2008 |publisher=BBC News }}
2. ^¹{{cite web|title=The world's oldest tree|url=http://www.nationalparksofsweden.se/choose-park---list/fulufjallet-national-park/experience/the-worlds-oldest-trees/#|publisher=National Parks of Sweden|accessdate=2 March 2017}}
3. ^¹{{cite news |url=http://scitech.blogs.cnn.com/2008/05/06/oldest-tree-in-world/ |title=World’s oldest tree points to global warming impact |accessdate=6 May 2008 |publisher=CNN |author=Landau, Elizabeth }}
4. ^¹{{cite web |url=http://news.nationalgeographic.com/news/2008/04/080414-oldest-tree.html |title=Oldest Living Tree Found in Sweden |accessdate=6 May 2008 |publisher=National Geographic |author=Owen, James }}
5. ^{{cite web|url=http://westinstenv.org/sosf/2008/04/20/worlds-oldest-tree-discovered/ |title=World’s Oldest Tree Discovered? |accessdate=12 April 2009 |date=20 April 2008 |publisher=Western Institute for Study of the Environment |deadurl=yes |archiveurl=https://web.archive.org/web/20090422205309/http://westinstenv.org/sosf/2008/04/20/worlds-oldest-tree-discovered/ |archivedate=April 22, 2009 }}
6. ^{{cite web |url=http://www.info.umu.se/NYHETER/PressmeddelandeEng.aspx?id=3061 |title=World’s oldest living tree discovered in Sweden |accessdate=6 May 2008 |publisher=Umeå University }}
7. ^{{cite news|author=Kirkebøen, Stein Erik |title=Verdens eldste tre |work=Aftenposten |language=Norwegian |date=24 April 2010 |page=14 |url=http://www.aftenposten.no/nyheter/iriks/article3620934.ece |accessdate=30 April 2010 |deadurl=yes |archiveurl=https://web.archive.org/web/20100427004427/http://www.aftenposten.no/nyheter/iriks/article3620934.ece |archivedate=April 27, 2010 }}
8. ^{{cite news |url=https://www.telegraph.co.uk/news/science/science-news/3339982/Worlds-oldest-tree-discovered-in-Sweden.html |title=World's oldest tree discovered in Sweden |accessdate=6 May 2008 |publisher=Telegraph Media Group |author=Highfield, Roger | location=London | date=17 April 2008}}
9. ^{{cite web|title=Activities in Naturum |url=http://www.dalarna.se/en-GB/Hotell/Fulufjallet1/naturum/Activities/ |accessdate=7 April 2014 |deadurl=yes |archiveurl=https://web.archive.org/web/20140408212853/http://www.dalarna.se/en-GB/Hotell/Fulufjallet1/naturum/Activities/ |archivedate=April 8, 2014 }}

Discovery and details

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