Sequoioideae

The three redwood subfamily genera are Sequoia from coastal California and Oregon, Sequoiadendron from California's Sierra Nevada, and Metasequoia in China. The redwood subfamily contains the largest and tallest trees in the world. These trees can live for thousands of years. Threats include logging, fire suppression,{{cite web| url = https://www.nps.gov/redw/learn/management/rxfire.htm| title = Prescribed Fire at Redwood National and State Parks - Redwood National and State Parks (U.S. National Park Service)}} and burl poaching.{{cite web | url=https://www.csmonitor.com/Environment/2014/0305/Why-redwood-burl-poaching-is-so-destructive | title=Why redwood burl poaching is so destructive | journal=Christian Science Monitor | date=5 March 2014 }}{{cite journal |doi=10.1016/j.forpol.2018.06.009 |title=The spatial pattern of redwood burl poaching and implications for prevention |journal=Forest Policy and Economics |volume=94 |pages=46–54 |year=2018 |last1=Kurland |first1=Justin |last2=Pires |first2=Stephen F |last3=Marteache |first3=Nerea |s2cid=158505170 }}

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.{{cn|date=January 2023}}

Multiple studies of both morphological and molecular characters have strongly supported the assertion that the Sequoioideae are monophyletic.{{cite journal |doi=10.2307/2419600 |jstor=2419600 |title=Phylogenetic Relationships Among the Genera of Taxodiaceae and Cupressaceae: Evidence from rbcL Sequences |journal=Systematic Botany |volume=19 |issue=2 |pages=253 |year=1994 |last1=Brunsfeld |first1=Steven J |last2=Soltis |first2=Pamela S |last3=Soltis |first3=Douglas E |last4=Gadek |first4=Paul A |last5=Quinn |first5=Christopher J |last6=Strenge |first6=Darren D |last7=Ranker |first7=Tom A }}{{Cite journal|title = Relationships Within Cupressaceae Sensu Lato: A Combined Morphological and Molecular Approach|year = 2000|last1 = Gadek|first1 = P.A.|last2 = Alpers|first2 = D.L.|last3 = Heslewod|first3 = M.M.|last4 = Quinn|first4 = C.J.|journal = American Journal of Botany|issue = 7|volume = 87 | doi = 10.2307/2657004|pmid=10898782|pages=1044–57|jstor = 2657004|doi-access = free}}{{Cite journal|title = Seed cone and ovule ontogeny in Metasequoia, Sequoia and Sequoiadendron (Taxodiaceae-Coniferales)|year = 1992|last1 = Takaso|first1 = T.|last2 = Tomlinson|first2 = P.B.|journal = Botanical Journal of the Linnean Society|volume = 109|doi=10.1111/j.1095-8339.1992.tb00256.x|pages=15–37}}{{Cite journal|title = Three Genome-based Phylogeny of Cupressaceae s.l: Further Evidence for the Evolution of Gymnosperms and Southern Hemisphere Biogeography|year = 2012|last1 = Yang|first1 = Z.Y.|last2 = Ran|first2 = J.H.|last3 = Wang|first3 = X.Q.|journal = Molecular Phylogenetics and Evolution|volume = 64|issue = 3|doi=10.1016/j.ympev.2012.05.004|pages=452–470|pmid=22609823}} Most modern phylogenies place Sequoia as sister to Sequoiadendron and Metasequoia as the out-group.{{Cite journal|title = Distribution of Living Cupressaceae Reflects the Breakup of Pangea|year = 2012|last1 = Mao|first1 = K.|last2 = Milne|first2 = R.I.|journal = Proceedings of the National Academy of Sciences|issue = 20|volume = 109|last3 = Zhang|first3 = L.|last4 = Peng|first4 = Y.|last5 = Liu|first5 = J.|last6 = Thomas|first6 = P.|last7 = Mill|first7 = R.R.|last8 = Renner|first8 = S.S.|doi=10.1073/pnas.1114319109|pages=7793–7798|pmid=22550176|pmc=3356613|bibcode = 2012PNAS..109.7793M|doi-access = free}} However, Yang et al. went on to investigate the origin of a peculiar genetic component in Sequoioideae, the polyploidy of Sequoia—and generated a notable exception that calls into question the specifics of this relative consensus.

A 2006 paper based on non-molecular evidence suggested the following relationship among extant species:

{{clade | style=font-size:75%

|1 = {{clade

|label1 = Sequoioideae|1 = {{clade

|1 = {{clade

|label1 = Metasequoia|1 = {{clade

|1 = M. glyptostroboides (dawn redwood)

}}

|2 = {{clade

|label1 = Sequoia|1 = {{clade

|1 = S. sempervirens (coast redwood)

}}

|label2 = Sequoiadendron|2 = {{clade

|1 = S. giganteum (giant sequoia)

}}

}}

}}

}}

|2 = Taxodioideae

}}

}}

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.{{Cite journal|last1=Stull|first1=Gregory W.|last2=Qu|first2=Xiao-Jian|last3=Parins-Fukuchi|first3=Caroline|last4=Yang|first4=Ying-Ying|last5=Yang|first5=Jun-Bo|last6=Yang|first6=Zhi-Yun|last7=Hu|first7=Yi|last8=Ma|first8=Hong|last9=Soltis|first9=Pamela S.|last10=Soltis|first10=Douglas E.|last11=Li|first11=De-Zhu|date=August 2021|title=Gene duplications and phylogenomic conflict underlie major pulses of phenotypic evolution in gymnosperms|url=https://www.nature.com/articles/s41477-021-00964-4/|journal=Nature Plants|language=en|volume=7|issue=8|pages=1015–1025|doi=10.1038/s41477-021-00964-4|pmid=34282286|s2cid=236141481|issn=2055-0278}}

Reticulate evolution refers to the origination of a taxon through the merging of ancestor lineages.

Polyploidy has come to be understood as quite common in plants—with estimates ranging from 47% to 100% of flowering plants and extant ferns having derived from ancient polyploidy.{{Cite journal|title = What we still don't know about polyploidy|year = 2010|journal = Taxon|last3 = Doyle|first3 = J.J.|last4 = Soltis|first4 = P.S.|author-link4 = Pamela S. Soltis|volume = 59|issue = 5|pages = 1387–1403|last1 = Soltis|first1 = D.E.|author-link1 = Douglas E. Soltis|last2 = Buggs|first2 = R.J.A. |jstor=20774036 |url=https://www.ingentaconnect.com/openurl?genre=article&eissn=1996-8175&volume=59&issue=&spage=1387&epage=1403&aulast=Soltis |doi = 10.1002/tax.595006|url-access = subscription}} Within the gymnosperms however it is quite rare. Sequoia sempervirens is hexaploid (2n= 6x= 66). To investigate the origins of this polyploidy Yang et al. used two single copy nuclear genes, LFY and NLY, to generate phylogenetic trees. Other researchers have had success with these genes in similar studies on different taxa.

Several hypotheses have been proposed to explain the origin of Sequoia's polyploidy: allopolyploidy by hybridization between Metasequoia and some probably extinct taxodiaceous plant; Metasequoia and Sequoiadendron, or ancestors of the two genera, as the parental species of Sequoia; and autohexaploidy, autoallohexaploidy, or segmental allohexaploidy.{{cn|date=January 2023}}

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 hybridization event involving Metasequoia and Sequoiadendron. Thus, Yang et al. hypothesize that the inconsistent relationships among Metasequoia, Sequoia, and Sequoiadendron could be a sign of reticulate evolution by hybrid speciation (in which two species hybridize and give rise to a third) among the three genera. However, the long evolutionary history of the three genera (the earliest fossil remains being from the Jurassic) make resolving the specifics of when and how Sequoia originated once and for all a difficult matter—especially since it in part depends on an incomplete fossil record.

• Metasequoia glyptostroboides {{small|Hu & W.C.Cheng}} - Dawn redwood; south-central China.
• Sequoiadendron giganteum {{small|(Lindl.) J.Buchh.}} - Giant sequoia, Giant redwood; western slopes of the Sierra Nevadas; California.
• Sequoia sempervirens {{small|(D.Don) Endl.}} - Coastal Redwood, California redwood; Northern California coast and extreme Southern Oregon.

Sequoioideae is an ancient taxon, with the oldest described Sequoioideae species, Sequoia jeholensis, recovered from Jurassic deposits.{{cite journal |last1=Ma |first1=Qing-Wen |last2=K. Ferguson |first2=David |last3=Liu |first3=Hai-Ming |last4=Xu |first4=Jing-Xian |date=2020 |title=Compressions of Sequoia (Cupressaceae sensu lato) from the Middle Jurassic of Daohugou, Ningcheng, Inner Mongolia, China |url=https://link.springer.com/article/10.1007/s12549-020-00454-z |journal=Palaeobiodiversity and Palaeoenvironments |volume=1 |issue=9 |page=1 |doi=10.1007/s12549-020-00454-z |s2cid=227180592 |access-date=9 March 2021 |ref=Jehol|url-access=subscription }}Ahuja M. R. and D. B. Neale. 2002. [http://www.rheinischesmuseumfuerphilologie.com/fileadmin/content/dokument/archiv/silvaegenetica/51_2002/51-2-3-93.pdf Origins of polyploidy in coast redwood (Sequoia sempervirens) and relationship of coast redwood (Sequoia sempervirens) to other genera of Taxodiaceae.] {{Webarchive|url=https://web.archive.org/web/20140102194158/http://www.rheinischesmuseumfuerphilologie.com/fileadmin/content/dokument/archiv/silvaegenetica/51_2002/51-2-3-93.pdf |date=2 January 2014 }} Silvae Genetica 51: 93–99. The fossil wood Medulloprotaxodioxylon, reported from the late Triassic of China, resembles Sequoiadendron giganteum and may represent an ancestral form of the Sequoioideae; this supports the idea of a Late Triassic Norian origin for this subfamily.{{cite journal |last1=Wan |first1=Mingli |last2=Yang |first2=Wan |last3=Tang |first3=Peng |last4=Liu |first4=Lujun |last5=Wang |first5=Jun |year=2017 |title=Medulloprotaxodioxylon triassicum gen. Et sp. Nov., a taxodiaceous conifer wood from the Norian (Triassic) of northern Bogda Mountains, northwestern China |journal=Review of Palaeobotany and Palynology |volume=241 |pages=70–84 |doi=10.1016/j.revpalbo.2017.02.009}}

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.{{cite journal|last=Chaney|first=Ralph W.|year=1950|title=Revision of Fossil Sequoia and Taxodium in Western North America Based on the Recent Discovery of Metasequoia|journal=Transactions of the American Philosophical Society|url=https://books.google.com/books?id=ZVwLAAAAIAAJ&pg=PA169|pages=172–236|volume=40 | issue = 3|place=Philadelphia|isbn=978-1422377055|access-date=1 January 2014|doi=10.2307/1005641|jstor=1005641|url-access=subscription}} A general cooling trend beginning in the late Eocene and Oligocene reduced the northern ranges of the Sequoioideae, as did subsequent ice ages.{{cite journal | last1 = Jagels | first1 = Richard | last2 = Equiza | first2 = María A. | year = 2007 | title = Why did Metasequoia disappear from North America but not from China? | journal = Bulletin of the Peabody Museum of Natural History | volume = 48 | issue = 2| pages = 281–290 | doi=10.3374/0079-032x(2007)48[281:wdmdfn]2.0.co;2| s2cid = 129649877 }} 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.{{cn|date=January 2023}}

The extinct genus Austrosequoia, known from the Late Cretaceous-Oligocene of the Southern Hemisphere, including Australia and New Zealand, has been suggested as a member of the subfamily.{{Cite journal |last=Mays |first=Chris |last2=Cantrill |first2=David J. |last3=Stilwell |first3=Jeffrey D. |last4=Bevitt |first4=Joseph J. |date=2018-05-28 |title=Neutron tomography of Austrosequoia novae-zeelandia e comb. nov. (Late Cretaceous, Chatham Islands, New Zealand): implications for Sequoioideae phylogeny and biogeography |url=https://www.tandfonline.com/doi/full/10.1080/14772019.2017.1314898 |journal=Journal of Systematic Palaeontology |language=en |volume=16 |issue=7 |pages=551–570 |doi=10.1080/14772019.2017.1314898 |issn=1477-2019|url-access=subscription }}File:Redwood tree in Oakland California (person for comparison)IMG 4881.jpg) in Oakland, California]]

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.{{cite news| last=Tapper | first=James | title=Hidden giants: how the UK’s 500,000 redwoods put California in the shade |newspaper=The Guardian | date=16 March 2024 | url=https://www.theguardian.com/environment/2024/mar/16/hidden-giants-how-the-uks-500000-redwoods-put-california-in-the-shade}} 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.{{cite web | last1=Sommer | first1=Lauren | last2=Kellman | first2=Ryan | title=Wildfires are killing California's ancient giants. Can seedlings save sequoia trees? | website=NPR | date=26 February 2024 | url=https://www.npr.org/2024/02/26/1232963498/sequoias-wildfires-climate-change-replanting | access-date=16 March 2024}}

• Temperate cloud forest of North American west coast (Sequoia forests)

{{Reflist|32em|refs =

{{cite journal | title = Evolution of taxodiaceous Cupressaceae (Coniferopsida) | url = https://www.sciencedirect.com/science/article/pii/S1439609207000049 | doi = 10.1016/j.ode.2006.03.001 | journal = Organisms Diversity & Evolution | date = August 2007 | volume = 7 | issue = 2 | pages = 124–135 | last1 = Schulz | last2 = Stützel| doi-access = free }}

}}

• {{cite web|url=https://home.nps.gov/redw/learn/nature/about-the-trees.htm|title=About the trees|publisher=National Park Service|access-date=10 January 2014}}
• {{cite web|url=https://www.nps.gov/redw/faqs.htm|title=A few basic facts about Redwoods, and Parks|publisher=National Park Service|access-date=10 January 2014}}
• {{cite web|url=http://www.bigtrees.org/|title=Calaveras Big Trees Association|access-date=10 January 2014}}
• {{cite web|url=http://www.dawnredwood.org/|title=Crescent Ridge Dawn Redwood Preserve|author=Hanks, Doug|year=2005|access-date=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.
• {{cite AV media|url=http://channel.nationalgeographic.com/channel/explorer/videos/climbing-redwood-giants/|archive-url=https://web.archive.org/web/20130412011955/http://channel.nationalgeographic.com/channel/explorer/videos/climbing-redwood-giants/|url-status=dead|archive-date=12 April 2013|title=Climbing Redwood Giants|medium=film|people=James Donald, John Rubin (directors)|publisher=National Geographic|year=2009}}
• {{cite episode|url=http://vimeo.com/56524336|title=Big trees|series=Notes from the Field tv|network=PBS|minutes=6|access-date=10 January 2014}}

• {{Commons category-inline|Sequoioideae}}

{{Cupressaceae}}

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Category:Plant subfamilies