Redwood facts for kids
Quick facts for kids Redwood |
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| Sequoiadendron giganteum | |
Scientific classification  |
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| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Division: | Pinophyta |
| Class: | Pinopsida |
| Order: | Pinales |
| Family: | Cupressaceae |
| Subfamily: | Sequoioideae |
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The redwoods are a subfamily of conifers, the Sequoideae. They are in the Cypress family Cupressaceae. It is most common in the coastal forests of Northern California and is possibly the largest tree in the world. There are three living genera in the subfamily. There were once more species of redwood trees, but most have become extinct.
These trees are pyrophytes: they have adapted to survive forest fires. Because fire is common in the regions where they grow, redwood trees have developed thick, fire-resistant bark. Their cones open only after a fire. Because fire control is better these days, the trees are endangered because they do not reproduce so well.
Redwood trees can grow to be very large. The largest species, Sequoiadendron giganteum, can reach up to 94.8 m tall and 17 m across. The tallest tree in the world is claimed to be a Sequoia sempervirens named Hyperion. The largest tree in the world by volume is claimed to be a Sequoiadendron giganteum named the General Sherman Tree, after William Tecumseh Sherman.
Contents
Range
South-central China
- The native habitat of Metasequoia glyptostroboides in Chongqing, Hubei, and Hunan in south-central China.
California, USA
- The native habitat of Sequoiadendron giganteum trees is only on the western slopes of the Sierra Nevada range of California.
- The native habitat of Sequoia sempervirens trees is only in the Northern California coastal forests ecoregion, on the Northern California coast and several miles into Oregon.
Description
The three redwood subfamily genera are Sequoia from coastal California and Oregon, Sequoiadendron from California's Sierra Nevada, and Metasequoia in China. The redwood species contains the largest and tallest trees in the world. These trees can live for thousands of years. Threats include: logging, fire suppression, climate change, and burl poaching.
Only two of the genera, Sequoia and Sequoiadendron, are known for massive trees. Trees of Metasequoia, from the single living species Metasequoia glyptostroboides, are much smaller.
Paleontology
Sequoioideae is an ancient taxon, with the oldest described Sequoioideae species, Sequoia jeholensis, recovered from Jurassic deposits. A genus Medulloprotaxodioxylon, reported from the late Triassic of China supports the idea of a Norian origin.
The fossil record shows a massive expansion of range in the Cretaceous and dominance of the Arcto-Tertiary Geoflora, especially in northern latitudes. Genera of Sequoioideae were found in the Arctic Circle, Europe, North America, and throughout Asia and Japan. A general cooling trend beginning in the late Eocene and Oligocene reduced the northern ranges of the Sequoioideae, as did subsequent ice ages. Evolutionary adaptations to ancient environments persist in all three species despite changing climate, distribution, and associated flora, especially the specific demands of their reproduction ecology that ultimately forced each of the species into refugial ranges where they could survive.
Conservation
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The entire subfamily is endangered. The IUCN Red List Category & Criteria assesses Sequoia sempervirens as Endangered (A2acd), Sequoiadendron giganteum as Endangered (B2ab) and Metasequoia glyptostroboides as Endangered (B1ab).
Introduced range
The two California redwood species, since the early 19th century, and the Chinese redwood species since 1948, have been cultivated horticulturally far beyond their native habitats. They are found in botanical gardens, public parks, and private landscapes in many similar climates worldwide. Plantings outside their native ranges particularly are found in California, the coastal Northwestern and Eastern United States, areas of China, Ireland, Germany, the United Kingdom, Australia and near Rotorua New Zealand. They are also used in educational projects recreating the look of the megaflora of the Pleistocene landscape.
See also
In Spanish: Secuoyas para niños
