Sequoioideae
Sequoioideae Temporal range:
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The trunk of a Metasequoia glyptostroboides | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Gymnospermae |
Division: | Pinophyta |
Class: | Pinopsida |
Order: | Cupressales
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Family: | Cupressaceae |
Subfamily: | Sequoioideae |
Genera | |
Sequoioideae, commonly referred to as Redwoods, is a
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,[1] illegal marijuana cultivation, and burl poaching.[2][3]
Only two of the genera, Sequoia and Sequoiadendron, are known for massive trees. Trees of Metasequoia, from the single living species Metasequoia glyptostroboides, are deciduous, grow much smaller (although are still large compared to most other trees) and can live in colder climates.[citation needed]
Taxonomy and evolution
Multiple studies of both morphological and molecular characters have strongly supported the assertion that the Sequoioideae are
Cladistic tree
A 2006 paper based on non-molecular evidence suggested the following relationship among extant species:[9]
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A 2021 study using molecular evidence found the same relationships among Sequoioideae species, but found Sequoioideae to be the sister group to the Athrotaxidoideae (a superfamily presently known only from Tasmania) rather than to Taxodioideae. Sequoioideae and Athrotaxidoideae are thought to have diverged from each other during the Jurassic.[10]
Possible reticulate evolution in Sequoioideae
Reticulate evolution refers to the origination of a taxon through the merging of ancestor lineages.
Several hypotheses have been proposed to explain the origin of Sequoia's polyploidy:
Yang et al. found that Sequoia was clustered with Metasequoia in the tree generated using the LFY gene but with Sequoiadendron in the tree generated with the NLY gene. Further analysis strongly supported the hypothesis that Sequoia was the result of a
Extant species
- Metasequoia glyptostroboides Hu & W.C.Cheng - Dawn redwood; south-central China.
- Sierra Nevadas; California.
- Sequoia sempervirens (D.Don) Endl. - Coastal Redwood, California redwood; Northern California coast and extreme Southern Oregon.
Paleontology
Sequoioideae is an ancient taxon, with the oldest described Sequoioideae species, Sequoia jeholensis, recovered from Jurassic deposits.[12][13] A genus Medulloprotaxodioxylon, reported from the late Triassic of China supports the idea of a Late Triassic Norian origin.[14]
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.[15] A general cooling trend beginning in the late Eocene and Oligocene reduced the northern ranges of the Sequoioideae, as did subsequent ice ages.[16] 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.[citation needed]
The extinct genus Austrosequoia is known from the Late Cretaceous-Oligocene of the Southern Hemisphere, including Australia and New Zealand.[17]
Conservation
In 2024, it was estimated that there were about 500,000 redwoods in Britain, mostly brought as seeds and seedlings from the US in the Victorian era.[18] 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). In 2024 it was reported that over a period of two years about one-fifth of all giant sequoias were destroyed in extreme wildfires in California.[19]
See also
- Temperate cloud forest of North America Westcoast (Sequoia forests)
References
- ^ "Prescribed Fire at Redwood National and State Parks - Redwood National and State Parks (U.S. National Park Service)".
- ^ "Why redwood burl poaching is so destructive". Christian Science Monitor. 5 March 2014.
- S2CID 158505170.
- JSTOR 2419600.
- ^ PMID 10898782.
- .
- ^ PMID 22609823.
- ^ PMID 22550176.
- .
- S2CID 236141481.
- JSTOR 20774036.
- S2CID 227180592. Retrieved 9 March 2021.
- ^ Ahuja M. R. and D. B. Neale. 2002. Origins of polyploidy in coast redwood (Sequoia sempervirens) and relationship of coast redwood (Sequoia sempervirens) to other genera of Taxodiaceae. Archived 2 January 2014 at the Wayback Machine Silvae Genetica 51: 93–99.
- .
- JSTOR 1005641. Retrieved 1 January 2014.
- S2CID 129649877.
- ISSN 1477-2019.
- ^ Tapper, James (16 March 2024). "Hidden giants: how the UK's 500,000 redwoods put California in the shade". The Guardian.
- ^ Sommer, Lauren; Kellman, Ryan (26 February 2024). "Wildfires are killing California's ancient giants. Can seedlings save sequoia trees?". NPR. Retrieved 16 March 2024.
Bibliography and links
- "About the trees". National Park Service. Retrieved 10 January 2014.
- "A few basic facts about Redwoods, and Parks". National Park Service. Retrieved 10 January 2014.
- "Calaveras Big Trees Association". Retrieved 10 January 2014.
- Hanks, Doug (2005). "Crescent Ridge Dawn Redwood Preserve". Retrieved 10 January 2014.
- de:Liste der dicksten Mammutbäume in Deutschland. List of Large Giant Redwoods in Germany
- IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. Downloaded on 10 January 2014.
- James Donald, John Rubin (directors) (2009). Climbing Redwood Giants (film). National Geographic. Archived from the original on 12 April 2013.
- "Big trees". Notes from the Field tv. 6 minutes in. PBS. Retrieved 10 January 2014.
External links
- Media related to Sequoioideae at Wikimedia Commons