World’s Biggest Trees

October 11, 2010

The Grizzly Giant Giant Saquoia tree in Mariposa Grove Worlds Biggest TreesThe Giant Sequoia (Sequoiadendron giganteum, Sierra redwood, Sierran redwood, or Wellington tree) is the sole living species in the genus Sequoiadendron, and one of three species of coniferous trees known as redwoods, classified in the family Cuoressaceae and in the subfamily Sequoioideae. The natural distribution zone of the giant sequoia is restricted to the limited western Sierra Nevada, California. in an area of only 144.16 square kilometres (35,620 acres). The giant sequoias are having difficulty reproducing in their original habitat (and very rarely reproduce in cultivation) due to the seeds only being able to grow successfully in mineral soils in full sunlight, free from competing vegetation. When fully grown, these trees typically require large amounts of water and are therefore often concentrated near streams.

Giant Sequoias are the world’s largest trees in terms of total volume and they grow to an average height of 50–85 metres (160–279 ft) and 6–8 metres (20–26 ft) in diameter. Record trees have been measured to be 94.8 metres (311 ft) in height and 17 metres (56 ft) in diameter. The oldest known Giant Sequoia based on ring count is 3,500 years old. The leaves are evergreen, awl-shaped, 3–6 mm long, and arranged spirally on the shoots. The seed cones are 4–7 cm long and mature in 18–20 months, though they typically remain green and closed for up to 20 years; each cone has 30-50 spirally arranged scales, with several seeds on each scale giving an average of 230 seeds per cone.

In September 2003 a fire, that lasted for 45 days, severely damaged the Washington tree. This was previously the second largest tree with a volume of 47,850 cubic feet (1,355 m3), but after losing over half its trunk in January 2005 due to a great snowstorm it is no longer of great size. Currently the largest sequoia by Volume (52,508ft³ [1,486.9m³]) is The General Sherman tree, it is estimated to weigh about 2100 tonnes, 274.9ft [83.8m] high and with a girth at ground of about 102ft [31m].

In addition to fire, there are also two animal agents for giant sequoia seed release. The more significant of the two is a longhorn beetle that lays eggs on the cones, into which the larvae then bore holes, and the Douglas Squirrel that gnaws on the fleshy green scales of younger cones. The squirrels are active year round, and some seeds are dislodged and dropped as the cone is eaten.

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