Notholithocarpus densiflorus
| Notholithocarpus densiflorus | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
The fruits of Notholithocarpus densiflorus resemble acorns |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name of the genus | ||||||||||||
| Notholithocarpus | ||||||||||||
| Manos , CHCannon & SHOh | ||||||||||||
| Scientific name of the species | ||||||||||||
| Notholithocarpus densiflorus | ||||||||||||
| ( Hook. & Arn. ) Manos, CHCannon & SHOh |
Notholithocarpus densiflorus ( Syn. : Notholithocarpus . (Hook & Arn) Rehder. , Pasania densiflora (Hook & Arn) Oerst... , Quercus densiflora Hook & Arn.. ) Is a deciduous tree art in the subfamily Quercoideae within the family of the Fagaceae (Fagaceae). This species is called "Tanoak" in English. It is the only species of thegenus Notholithocarpus , thus monotypical .
description
Notholithocarpus densiflorus is an evergreen tree that grows up to 10 meters in height, but also up to 45 meters in some preferred natural locations, and forms a broadly spreading crown . The tree is slow-growing and can live to be 300 to 350 years old. The bark of older trees is deeply furrowed to fissured.
The root system consists of a deep taproot and intense, far-reaching lateral roots. The roots fix nitrogen from the air with the help of bacteria. Seedlings seem to grow very slowly in the first few years - they develop the taproot first and then root tubers just below the surface of the soil. In young plants that grow in deep shade, the trunk dies after several years and sprouts again from the tuber. Only when there is finally a gap in the canopy will the trunks continue to grow upwards. Older trees can also regenerate themselves from these tubers, for example after forest fires or after the tree has been felled.
The alternate leaves are leathery, egg-shaped, -lanceolate to obovate, -eilanceolate or elliptical, 6 to 12 cm long and 2.5 to 6 cm wide. The edge of the leaf is roughly serrated or serrated. The rounded to pointed or pointed leaves sit on a short, hairy stem. The upper side of the leaf is smooth and dark green; the underside of the leaf is initially densely hairy rust-brown; later it is only thinly haired and appears blue-gray due to waxy frosting. Young twigs are also hairy.
Flowering time is from June to August; sometimes flowers appear in spring or autumn. Notholithocarpus densiflorus is monoecious . The male inflorescences are catkins , they are about 8 to 10 cm long and are in leaf axils on the shoots newly formed in spring. The unisexual and white-brownish flowers give off an unpleasant odor. There are a few female and greenish flowers at the base of the male inflorescences, their arrangement is similar to that of the sweet chestnut . The flowers each have a simple flower envelope , the petals are missing. The male flowers have 10–12 stamens , the female a subordinate ovary with three stylus branches .
The fruit has the shape of an acorn , is 2 to 4 cm long and is only enclosed at the base by a narrow fruit cup with many chopped bristles and spikes. However, the fruits (similar to hazelnuts) have a hard, woody shell. They ripen in October of the year following flowering, are bitter and therefore inedible without treatment. The fruits only develop in the second year.
Distribution and location
The species is native to western North America in a narrow strip along the Pacific coast from southern Oregon to California . The occurrences are mainly on mountain slopes up to 1500 m altitude, the climate is rich in precipitation in winter with a pronounced dry period in summer. Particularly dry or waterlogging locations within the distribution area are not populated.
Is associated Notholithocarpus densiflorus often with a coast redwood and Douglas fir on dry sites with Arbutus menziesii . Despite the competition from tall conifers, the species can hold its own in the long term and, with the seedlings' strategy of waiting for gaps in the canopy, can also spread in the shade.
The shrub -shaped variety echinoides grows in a narrow height range, which is slightly higher than the distribution area of the tree-shaped variety lithocarpus .
Systematics
The species was first described as Quercus densiflorus by William Jackson Hooker and George Arnott Walker Arnott in 1840 in their work The botany of Captain Beechey's voyage . It was later transformed into Quercus subg. Pasania classified, which was later raised to an independent genus. Alfred Rehder classified it in 1917 in the predominantly Asian genus Lithocarpus , in which it remained for about 90 years.
Notholithocarpus densiflorus is the only species in the genus. In a phylogenomic work (with additional processing of the pollen morphology) it was shown in 2008 that it cannot belong to the genus Lithocarpus , with which it does not form a common clade . Later, leaf morphological features were identified which, compatible with this, suggest a closer relationship to the genus Quercus .
A dwarf form in the mountains was distinguished as Notholithocarpus densiflorus var. Echinoides (R.Br.) Manos, CHCannon & SHOh (first described in Oregon in 1871 as Quercus echinoides ). This grows in the mountains of northern California (south to Mariposa County ) and southern Oregon. The shrub-like growing variety only reaches heights of about 3 meters, rarely higher. The leaves are also smaller, less than 6 cm in length.
ecology
The pathogen Phytophthora ramorum has been observed in the stocks of Lithocarpus densiflorus since around 1995, causing the trees to die in large parts of the distribution area. The disease is described as "sudden oak death". The pests newly introduced with tree nursery plants attack a large number of tree and shrub species, with Notholithocarpus densiflorus being the most susceptible. Regionally, up to a hundred percent of the trees are infested and dead, so that the extinction of the species has been feared. It is the only American tree species that is affected by leaves, branches and trunks. Although there are certain hereditary differences in susceptibility, no resistant populations have been found.
use
The bark contains up to 29% tannins; it was previously used for tanning. Since the tree species used to be regarded as belonging to the oak, the English name "Tanoak" ("tan" = tan, "oak" = oak) explains itself. Even before the current threat, the species had become rarer for decades due to overexploitation for industrial tanning.
The hard wood is mainly used as firewood .
After the bitter substances had been removed, the seeds were eaten like acorns by native Indians, for example by soaking them several times in hot water or by storing them for months in flowing water.
literature
- C. Frank Brockman: Trees of North America. St. Martin's Press, New York 2001, ISBN 978-1-58238-092-6 , p. 118 (English).
Web links
- Entry in GRIN Taxonomy for Plants (English)
- Entry at ITIS (English)
- Entry at USDA (English)
- Description at Plants for a Future (English)
Individual evidence
- ↑ American Forests: National Register for Big trees (Updated April 17, 2019).
- ^ A b John C. Tappeiner, Philip M. McDonald, Douglass F. Roy: Tanoak . In: US Department of Agriculture (Ed.): Silvics of North America: 2. Hardwoods . ( fed.us [accessed February 19, 2007]).
- ^ Diana L. Immel: Tanoak . In: US Department of Agriculture (Ed.): National Plant Data Center . ( plants.usda.gov [PDF; accessed February 19, 2007]).
- ^ Nancy E. McMurray: Lithocarpus densiflorus . In: US Department of Agriculture (Ed.): Fire Effects Information System . ( fed.us [accessed February 19, 2007]).
- ↑ Paul S. Manos, Charles H. Cannon, Sang-Hun Oh: Phylogenetic Relationships and Taxonomic Status Of the Paleoendemic Fagaceae Of Western North America: Recognition Of A New Genus, Notholithocarpus. In: Madroño. 55, 2008, 181-190, doi: 10.3120 / 0024-9637-55.3.181 .
- ↑ Min Deng, Qiansheng Li, Shuting Yang, Yan Chun Liu, Jin Xu: Comparative morphology of leaf epidermis in the genus Lithocarpus and its implication in leaf epidermal feature evolution in Fagaceae. In: Plant Systematics and Evolution. 299, 2013, 659-681. doi: 10.1007 / s00606-012-0751-0 .
- ↑ Lithocarpus densiflorus . Flora of North America online, Vol. 3: Magnoliophyta: Magnoliidae and Hamamelidae. printed version Nancy R Morin (editor), Oxford University Press, 1997.
- ^ Katherine J. Hayden, Alejandro Nettel, Richard S. Dodd, Matteo Garbelotto: Will all the trees fall? Variable resistance to an introduced forest disease in a highly susceptible host. In: Forest Ecology and Management. 261, 2011, 1781–1791, doi: 10.1016 / j.foreco.2011.01.042 .
- ↑ Frederica Bowcutt: Tanoak Target: The Rise and Fall of Herbicide Use on a Common Native Tree. In: Environmental History. 16 (2), 2011, 197-225, doi: 10.1093 / envhis / emr032 .