| Sequoioideae | |
|---|---|
| Sequoiadendron giganteum | |
| Conservation status | |
| Scientific classification | |
| Kingdom: | Plantae |
| Division: | Pinophyta |
| Class: | Pinopsida |
| Order: | Pinales |
| Family: | Cupressaceae |
| Subfamily: | Sequoioideae |
| Genera | |
Sequoioideae is a subfamily in the Cupressaceae family, with three genera.[1]
Contents |
The three redwood subfamily genera are: Sequoia and Sequoiadendron of California and Oregon, USA; and Metasequoia in China. The redwood species contains the largest and tallest trees in the world. These trees can live to an old age, with some for hundreds to thousands of years. This is an endangered subfamily due to habitat losses from: fire ecology suppression, development, and air pollution.
The Sequoia and Sequoiadendron genera are massive trees. The Metasequoia genus, with the living species Metasequoia glyptostroboides, are smaller trees. The trees in Sequoioideae hold the record for the tallest and largest trees in the world. The tallest tree in the world is a Sequoia sempervirens, the Hyperion Tree. The largest tree in the world is a Sequoiadendron giganteum, the General Sherman Tree.
The Sequoioideae is an ancient taxa. The first Seqoioideae, Sequoia jeholensis, was discovered in Jurassic deposits[2]. The fossil record shows a massive expansion of range in the Cretaceous and dominance of the Arcto-Tertiary flora, especially in northern latitudes. Genera of the Sequoioideae were found in the Arctic Circle, Europe, North America, and throughout Asia and Japan[3]. A general cooling trend beginning in the late Eocene and Oligocene reduced the northern ranges of the Sequoioideae, as did subsequent ice ages[4]. The entire paleohistory of the Sequoioideae has been a story of migration rather than adaptation. Evolutionary adaptations to ancient environments persisted in all three species despite changing climate, distribution, and associated flora. Morphological stasis over millennia ultimately forced these species into extremely limited ranges where they persist, though in a very vulnerable state.
The entire subfamily Sequoioideae are endangered flora. The Sequoiadendron giganteum, Sequoia sempervirens are Vulnerable species, and Metasequoia glyptostroboides is a critically endangered species on the IUCN Red List.
The two California redwood species, since the early 19th century, and the Chinese redwood species since 1948, have been cultivated horticulturally near and far beyond their origins. 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, Germany, England and the United Kingdom. They are also used in educational projects recreating the look of the Pleistocene landscape of megaflora.