Hesperocyparis abramsiana
Santa Cruz cypress | |
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Santa Cruz Cypress in a tree nursery. | |
Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Gymnospermae |
Division: | Pinophyta |
Class: | Pinopsida |
Order: | Cupressales
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Family: | Cupressaceae |
Genus: | Hesperocyparis |
Species: | H. abramsiana
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Binomial name | |
Hesperocyparis abramsiana (C.B.Wolf) Bartel
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Range map | |
Synonyms[3] | |
List
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The Santa Cruz cypress (Hesperocyparis abramsiana; formerly classified as Cupressus abramsiana) is a species of North American tree within the
Physical description
Individuals can grow 10 to 25 meters tall with branches 5–10 cm in diameter covering the trunk to nearly the ground. The shape of the tree is pyramidal, with branches longer toward the base.[8] The tree’s leaves are light green and scale-like and can grow up to 15mm in length, persisting on branches for many years. The bark of the trunk is fibrous with thin grey vertical stripes. Individuals begin to produce cones at 11 years in age. Pollen cones can grow up to 4mm long and produce large amounts of pollen that spread in the wind. Female seed cones are produced annually on the tree and grow up to 20 to 30mm in diameter. They remain on the tree until the supporting branches die, typically as a result of natural fires. Individuals can live beyond 100 years, with one of the oldest individuals identified as being between 127 and 162 years old.[9]
Reproduction and phenology
The reproductive age of the Santa Cruz cypress is on average 11 years of age. Seed viability falls to 10 percent by the time a tree is 30 years old.[8] Like some other coniferous trees, the seed-bearing cones of the Santa Cruz cypress depend on fire to heat open the cone and release the seeds. The fires burn the vegetation in the area, including the parent tree. The seeds of the cypress are then able to germinate without the competition of other plants in the area.[9]
Taxonomy
As with
As of 2024[update] Hesperocyparis abramsiana is considered the correct name for the species, with no subdivisions, by Plants of the World Online,[3] World Flora Online,[10] and the Gymnosperm Database.[11]
Names
The species was named by Wolf to honor Dr LeRoy Abrams, a botanist at Stanford University. Abrams had also studied the trees with Wolf in 1937.[5]
Ecology
The habitat of the Santa Cruz cypress consists of the
Distribution
This species grows only in a 16 km2 (6.2 mi2 or 356 acres) stretch of land in California. Within this range are five different localities with stands of the trees. The range covers parts of the Santa Cruz Mountains and the Santa Cruz and San Mateo counties.[5] Historically, the populations had a much larger range, covering at least 76 km2 (30 mi2 or 19,200 acres).[12] The estimated total population is less than 300 individuals, but abundance varies between localities. Some stands of the cypress only have a few individuals left.[1]
One exceedingly rare type, the Butano cypress, exists in only one grove, of about 10 acres.[13] This grove was described by William Dudley in the early 1900s.[13] All of the adult trees died during the CZU Lightning Complex fires in 2020.[13] Thousands of young Butano cypress seedlings were found growing in the grove in 2022.[13]
Conservation status
The
The
Current population threats
Alteration of fire regimes
The modern habitat of the Santa Cruz cypress no longer experiences fires at its natural frequency. Without disturbances like fire, the trees undergo little population growth and decreasing reproduction. Existing trees become post-reproductive and no longer produce viable seeds. Human-created fires can occur too often, destroying immature trees before reaching reproductive age. The U.S. Fishing and Wildlife Service cited the altered fire regime as one of the most important threats to the populations.[7]
Nonnative species
Nonnative species serve as competition and habitat modifiers that can limit cypress success. Acacia dealbata and Genista monspessulana impact Santa Cruz populations by blocking sunlight and by competing for soil space to germinate.[9] More nonnative invasions are possible in the future due to the cypress’ closeness to residential areas. The foot travel and human activities in these areas can bring more invasive species.
Genetic Introgression
In 2016, the conservation status of the Santa Cruz cypress was reduced to threatened. The cited reasoning was a decrease in threats against their habitat.
Additional threats
Another major human-derived threat to the species is climate change. Rising temperatures may push populations northwards, as well as further alter the fire regime. The species is also damaged by vandalism and unauthorized recreational activities. Actions like carving into bark damage the trees, encouraging infections and disease.[7] In the past, the conversion of habitat into agricultural lands and residential areas was a major threat. But as populations became protected and preserved, the threat has since decreased.[1]
Current conservation efforts
The
Updated resource-use plans and ordinances from the Santa Cruz and San Mateo counties currently protect some populations. More than half of all the individuals in the species occur on private lands owned by conservationists. State and county parks protect the remaining individuals. Watershed management plans have begun for some of these areas to aid in protections.[7]
References
- ^ a b c Farjon, A. 2013. Cupressus goveniana var. abramsiana. The IUCN Red List of Threatened Species 2013: e.T34000A2839959. https://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T34000A2839959.en.
- ^ U.S. Fish and Wildlife Service. 2016. Endangered and Threatened Wildlife and Plants; Reclassifying Hesperocyparis abramsiana (=Cupressus abramsiana) as Threatened. Federal Register Vol. 81. No. 33. https://www.govinfo.gov/link/fr/81/8408?link-type=pdf
- ^ a b c "Hesperocyparis abramsiana (C.B.Wolf) Bartel". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 28 February 2024.
- ^ Lyons, Kathleen, and U.S. Fish Wildlife Service. Recovery Plan for the Santa Cruz Cypress (Cupressus Abramsiana). U.S. Fish and Wildlife Service, 1998.
- ^ a b c Wolf, Carl B. (1948). "Taxonomic and Distributional Studies of the New World Cypresses". Aliso: A Journal of Systematic and Floristic Botany. 1 (1): 215–222. Retrieved 28 February 2024.
- ^ a b U.S. Fish and Wildlife Service. 1987. Endangered and threatened wildlife and plants; Determination of endangered status for Cupressus abramsiana (Santa Cruz cypress). Federal Register 52: 675-679. https://ecos.fws.gov/docs/federal_register/fr1017.pdf
- ^ a b c d e f g U.S. Fish and Wildlife Service. 2016. Endangered and Threatened Wildlife and Plants; Reclassifying Hesperocyparis abramsiana (=Cupressus abramsiana) as Threatened. Federal Register Vol. 81. No. 33. https://www.govinfo.gov/link/fr/81/8408?link-type=pdf
- ^ a b Peattie, Donald Culross. A Natural History of Western Trees; Illustrated by Paul Landacre. Boston: Houghton Mifflin, 1953. p . 246-247. Print.
- ^ a b c d e U.S. Fish and Wildlife Service. 2009. Cupressus abramsiana 5-Year Review: Summary and Evaluation. Federal Register 81: 8408-8418.
- ^ "Hesperocyparis abramsiana (C.B.Wolf) Bartel". World Flora Online. Retrieved 28 February 2024.
- ^ Earle, Christopher J. (2023). "Hesperocyparis abramsiana (Santa Cruz cypress) description". The Gymnosperm Database. Retrieved 28 February 2024.
- ^ a b c d IUCN 2020. The IUCN Red List of Threatened Species. Version 2020-1. https://www.iucnredlist.org.
- ^ a b c d Kreiger, Lisa M. (27 March 2022). "These Bay Area trees existed nowhere else on the planet. Did they survive a devastating wildfire?". The Mercury News.
- PMID 21712198.