| 词条 | Exploding tree |
| 释义 |
Exploding trees occur when stresses in a tree trunk increase leading to an explosion. These explosions can be caused by three different factors: cold, lightning, and fire. CausesColdCold weather will cause some trees to explode by freezing the sap, because it contains water, which expands as it freezes, creating a sound like a gunshot.[1][2] The sound is produced as the tree bark splits, with the wood contracting as the sap expands.[2][4] John Claudius Loudon described this effect of cold on trees in his Encyclopaedia of Gardening, in the entry for frosts, as follows{{ref|Hutton|1}}: {{quote|text=The history of frosts furnishes very extraordinary facts. The trees are often scorched and burnt up, as with the most excessive heat, in consequence of the separation of water from the air, which is therefore very drying. In the great frost in 1683, the trunks of oak, ash, walnut, and other trees, were miserably split and cleft, so that they might be seen through, and the cracks often attended with dreadful noises like the explosion of fire-arms. In the frost of 1837–8 large bushes of heath had their stems split by the frost into shreds, and the wood of the evergreen oak and that of the sweet bay was cracked and split in a similar manner.|sign=John Claudius Loudon|source=Encyclopaedia of Gardening[3][4]}}Henry Ward Beecher records anecdotal evidence of the wood from which instrument cases and carrying boxes were splitting in temperatures of {{convert|-70|F|C}} in Captain Bach's travels near the Great Slave Lake.[3] Linda Runyon, author of books on wilderness living, recounts her experience of the effect of cold on maple trees as follows: {{quote|text=I was relaxing in front of a fire in the crispness of early morning when Crack! A sound like an explosion came from behind me in the woods. I scanned the trees and saw that a maple tree had "exploded". The explosion caused a big crack in the tree about three feet high. When a winter wind stirs the frozen trees, they sometimes appear to burst vertically. When it was 40 degrees below zero at night, I lay awake and listened to the trees explode. That's a true wilderness thermometer!|sign=Linda Runyon|source=The Essential Wild Food Survival Guide [5]}}Wally and Shirley Loudon reported the effect of the freeze of December 1968 upon their orchard in Carlton, Washington as follows:[4] {{quote|text=We saw 47 below on our porch, and we didn't look again. I would hear these bangs and I blamed it on the house expanding or contracting, or whatever, from the cold, but it was the trees exploding. It was the bark bursting, and you could hear it. That's how wild it was.|sign=Shirley Loudon|source="Freezes are becoming a distant memory", Good Fruit Grower[4][6]}}To the Sioux of The Dakotas and the Cree, the first new moon of the new year is known, in various dialects, as the "Moon of the Cold-Exploding Trees".[7][8][9][10] Tree sap is a supercooled liquid in cold temperatures.[11] John Hunter observed, in his Treatise on the Blood, that tree sap within a tree freezes some 17 degrees Fahrenheit below its nominal freezing point.[12][13] LightningTrees can explode when struck by lightning.[4][14][15][16] The strong electric current is carried mostly by the water-conducting sapwood below the bark, heating it up and boiling the water. The pressure of the steam can make the trunk burst.[4][16] This happens especially with trees whose trunks are already dying or rotting.[4][17][18] The more usual result of lightning striking a tree, however, is a lightning scar, running down the bark, or simply root damage, whose only visible sign above ground is branches that were fed by the root dying back.[16][19] FireExploding trees also occur during forest fires[20] and are a risk to smokejumpers.[21][22][23] In Australia, the native eucalyptus trees are also known to explode during bush fires due to the high flammability of vaporised eucalyptus oil produced by the tree naturally.[24][25] April fools' hoaxExploding trees were the subject of a 2005 April Fools' Day hoax in the USA, covered by National Public Radio, stating that maple trees in New England had been exploding due to a failure to collect their sap, causing pressure to build from the inside.[26] The root pressure in a maple tree is approximately 0.1MPa, one standard atmosphere, which is nowhere near enough to cause a tree to explode.[27][28] See also{{Portal|Trees}}
Footnotes
References1. ^{{cite book|title=Life at a High Altitude|series=Life in extreme environments|author=Judith Levin|publisher=The Rosen Publishing Group|year=2004|isbn=0-8239-3987-1|id={{ISBN|9780823939879}}|page=10}} 2. ^1 {{cite journal|date=May 2000|volume=28|issue=186, number 4|issn=0277-867X|publisher=Active Interest Media, Inc.|work=Backpacker Magazine|page=72|title=Pop Goes the Forest|author=Jonathan Dorn}} 3. ^1 {{cite book|title=Plain and pleasant talk about fruits, flowers and farming|author=Henry Ward Beecher|publisher=Derby & Jackson|year=1859|location=New York|page=100}} 4. ^{{cite encyclopaedia|article=Frost|encyclopedia=The New Popular Encyclopedia|editor=Charles Annandale|volume=VI|publisher=The Gresham Publishing Company|location=London and Glasgow|page=37|year=1901}} 5. ^{{cite book|title=The Essential Wild Food Survival Guide|author=Linda Runyon|publisher=Lulu.com|year=2007|isbn=0-936699-10-8|id={{ISBN|9780936699103}}|page=97}} 6. ^{{cite journal|url=http://goodfruit.com/issues.php?article=838&issue=29|title=Freezes are becoming a distant memory|author=Geraldine Warner|date=1996-02-01|volume=47|issue=3|work=Good Fruit Grower}} 7. ^{{cite book|title=Strange empire: a narrative of the Northwest|series=Borealis Books|author=Joseph Kinsey Howard|publisher=Minnesota Historical Society Press|year=1994|isbn=0-87351-298-7|id={{ISBN|9780873512985}}|page=43}} 8. ^{{cite book|title=The rise of Theodore Roosevelt|series=Modern Library Paperbacks Series|author=Edmund Morris|publisher=Modern Library|year=2001|isbn=0-375-75678-7|id={{ISBN|9780375756788}}|page=365}} 9. ^{{cite book|title=The grasslands of the United States: an environmental history|series=Nature and human societies|author=James Earl Sherow|publisher=ABC-CLIO|year=2007|isbn=1-85109-720-1|id={{ISBN|9781851097203}}|page=105}} 10. ^{{cite book|title=The revenge of Thomas Eakins|series=Henry McBride series in modernism and modernity|author=Sidney Kirkpatrick|publisher=Yale University Press|year=2006|isbn=0-300-10855-9|id={{ISBN|9780300108552}}|page=337}} 11. ^{{cite book|title=The physics of hockey|author=Alain Haché|publisher=JHU Press|year=2002|isbn=0-8018-7071-2|id={{ISBN|9780801870712}}|page=8}} 12. ^{{cite book|title=Familiar science, or, the scientific explanation of the principles of natural and physical science: and their practical and familiar applications to the employments and necessities of common life|author=David Ames Wells|publisher=Childs & Peterson|location=Philadelphia|year=1856|pages=129–130}} 13. ^{{cite book|title=The Works of John Hunter: with notes|author=John Hunter|editor=James F. Palmer|publisher=Longman, Rees, Orme, Brown, Green, and Longman|location=London|year=1835|volume=III|page=107|authorlink=John Hunter (surgeon)}} 14. ^{{cite web|url=http://pinetum.org/lightning.htm|title=Sequoiadendron giganteum — A 120 years old tree exploded by lightning|date=2001-02-22|publisher=Arboretum de Villardebelle}} 15. ^{{cite web|url=http://australiasevereweather.com/storm_news/2006/docs/200602-04.htm|title=Funnel cloud observed and lightning explodes a tree in the Lismore area|date=2006-02-12|author=Michael Bath|work=Storm News and Chasing|publisher=Michael Bath and Jimmy Deguara}} 16. ^1 2 {{cite journal|url=http://newton.dep.anl.gov/natbltn/400-499/nb458.htm|title=Nature Bulletin No. 458-A|date=1972-05-20|publisher=Forest Preserve District of Cook County|author1=George W. Dunne |author2=Roland F. Eisenbeis }} 17. ^{{cite web|url=http://wvlightning.com/trees.shtml|title=Tree, nature's lightning rod|work=West Virginia Lightning}} 18. ^{{cite journal|work=Popular Science|date=August 1959|volume=175|issue=2|issn=0161-7370|publisher=Bonnier Corporation|title=The Awesome Miracle of Lightning|author=Ira Wolfert|pages=186}} 19. ^{{cite book|title=The organic gardener's handbook of natural insect and disease control|author1=Barbara W. Ellis |author2=Fern Marshall Bradley |author3=Helen Atthowe |publisher=Rodale|year=1996|isbn= 9780875967530|pages=392}} 20. ^{{cite book|title=Rain Forests of the World|editor=Rolf. E. Johnson|publisher=Marshell Cavendish |location=New York|page=238|accessdate=2009-09-25|url=https://books.google.com/books?id=8UDxeHNx4tsC&lpg=PA238&dq=exploding%20trees%20fire&pg=PA238#v=onepage&q=exploding%20trees%20fire | isbn=978-0-7614-7254-4|date=January 2002}} 21. ^{{cite journal|year=1968|journal=The National Geographic Magazine|volume=134|accessdate=}} 22. ^{{cite journal|last=Weick|first=Karl E.|year=1993|title=The collapse of sensemaking in organizations: the Mann Gulch disaster|journal=Administrative Science Quarterly|doi=10.2307/2393339|volume=38|pages=628}} 23. ^{{cite book|title=Fire Fighters: Stories of Survival from the Front Lines of Firefighting |editor=Clint Willis|publisher=Da Capo Press|year=2002}} 24. ^{{cite journal|url=http://library.csustan.edu/bsantos/section3.htm|title=The Eucalyptus of California — Section Three: Problems, Cares, Economics, and Species|author=Robert L. Santos|publisher=Alley-Cass Publications|location=Denair, California|year=1997|deadurl=yes|archiveurl=https://web.archive.org/web/20100602175115/http://library.csustan.edu/bsantos/section3.htm|archivedate=2010-06-02|df=}} 25. ^{{cite journal|url=http://robertsward.com/eucmore.htm|title=Eucalytus Roulette (con't) Excerpted from America's Largest Weed|author=Ted Williams|work=Audubon Magazine|date=January–February 2002|publisher=Robert Sward}} 26. ^{{cite web|url=https://www.npr.org/templates/story/story.php?storyId=4571982|title=April Fool's: New England Suffers Maple Woes|author=Robert Siegel|date=2005-04-01|publisher=National Public Radio}} 27. ^1 2 3 4 5 6 {{cite web|url=http://wonderquest.com/genetic-pets-exploding-trees.htm|title=Buying genetic pets; Exploding sap trees; Non-blinking cows|first=April|last=Holladay|date=2007-02-07|work=WonderQuest}} 28. ^{{cite web|url=http://www.botany.hawaii.edu/faculty/webb/BOT311/bot311-00/PlantWatMove/Transpiration.htm|title=Transpiration|first=David T.|last=Webb|work=BOT 311 Spring 2006 Syllabus|publisher=University of Hawaii at Manoa}} 29. ^{{cite encyclopaedia|article=Frost|encyclopedia=Mathematical and Philosophical Dictionary|year=1795|author=Charles Hutton|pages=520|location=London|publisher=J. Johnson|url=http://archimedes.mpiwg-berlin.mpg.de/cgi-bin/toc/toc.cgi?page=548;dir=hutto_dicti_078_en_1795;step=textonly}} External links
2 : Explosions|Trees |
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