''Notholithocarpus densiflorus'', commonly known as the tanoak or tanbark-oak, is a

broadleaf tree A broad-leaved, broad-leaf, or broadleaf tree is any tree within the diverse botanical group of angiosperms that has flat leaves and produces seeds inside of fruits. It is one of two general types of trees, the other being a conifer, a tree with n ...

in the family

Fagaceae The Fagaceae are a family of flowering plants that includes beeches, chestnuts and oaks, and comprises eight genera with about 927 species. Fagaceae in temperate regions are mostly deciduous, whereas in the tropics, many species occur as ever ...

, and the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specim ...

of the genus ''Notholithocarpus''. It is native to the far western

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

, particularly

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

and

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

. It ranges from in height, with a trunk diameter of .

Description

It can reach tall in the

California Coast Ranges The Coast Ranges of California span from Del Norte or Humboldt County, California, south to Santa Barbara County. The other three coastal California mountain ranges are the Transverse Ranges, Peninsular Ranges and the Klamath Mountains. ...

, though is more usual, and can have a trunk diameter of . The

bark Bark may refer to: * Bark (botany), an outer layer of a woody plant such as a tree or stick * Bark (sound), a vocalization of some animals (which is commonly the dog) Places * Bark, Germany * Bark, Warmian-Masurian Voivodeship, Poland Arts, e ...

is fissured, and ranges from gray to brown. The

leaves A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

are alternate, , with toothed margins and a hard, leathery texture, and persist for three to four years. At first they are covered in dense orange-brown scurfy hairs on both sides, but those on the upper surface soon wear off; those on the under surface persist longer but eventually wear off too. The

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiosper ...

is an

acorn The acorn, or oaknut, is the nut of the oaks and their close relatives (genera '' Quercus'' and '' Lithocarpus'', in the family Fagaceae). It usually contains one seed (occasionally two seeds), enclosed in a tough, leathery shell, and b ...

long and 2 cm in diameter, very similar to an oak

, but with a very hard, woody nut shell more like a

hazel The hazel (''Corylus'') is a genus of deciduous trees and large shrubs native to the temperate Northern Hemisphere. The genus is usually placed in the birch family Betulaceae,Germplasmgobills Information Network''Corylus''Rushforth, K. (1999). ...

nut. The nut sits in a cup during its 18-month maturation; the outside surface of the cup is rough with short spines. The nuts are produced in clusters of a few together on a single stem. Currently, the largest known tanoak specimen is on private timberland near the town of Ophir, Oregon. It has a circumference of , is about in

diameter at breast height Diameter at breast height, or DBH, is a standard method of expressing the diameter of the trunk or bole of a standing tree. DBH is one of the most common dendrometric measurements. Tree trunks are measured at the height of an adult's breast ...

, and is tall with an average crown spread of .

''Notholithocarpus densiflorus'' var. ''echinoides''

Members of populations in interior California (in the northern

Sierra Nevada The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primar ...

) and the

Klamath Mountains The Klamath Mountains are a rugged and lightly populated mountain range in northwestern California and southwestern Oregon in the western United States. As a mountain system within both the greater Pacific Coast Ranges and the California Coast ...

into southwest Oregon are smaller, rarely exceeding in height and often shrubby, with smaller leaves, long; these are separated as "dwarf tanoak", ''Notholithocarpus densiflorus'' var. ''echinoides''. The variety intergrades with the type in northwest California and southwest Oregon. Tanoak grows as a shrub on

serpentine soil Serpentine soil is an uncommon soil type produced by weathered ultramafic rock such as peridotite and its metamorphic derivatives such as serpentinite. More precisely, serpentine soil contains minerals of the serpentine subgroup, especially anti ...

Taxonomy

By 2008, the species was moved into a new genus, ''Notholithocarpus'' (from ''Lithocarpus''), based on multiple lines of evidence. It is most closely related to the north temperate oaks (''Quercus'') and not as closely related to the Asian tropical stone oaks (''

Lithocarpus ''Lithocarpus'' is a genus in the beech family, Fagaceae. Trees in this genus are commonly known as the stone oaks and differ from ''Quercus'' primarily because they produce insect-pollinated flowers on erect spikes and the female flowers hav ...

'', where it was previously placed), but instead is an example of convergent morphological evolution. While related to oaks (as well as

chestnut The chestnuts are the deciduous trees and shrubs in the genus ''Castanea'', in the beech family Fagaceae. They are native to temperate regions of the Northern Hemisphere. The name also refers to the edible nuts they produce. The unrel ...

s), the name is written as 'tanoak' because it is not a true oak.

Distribution

It is native to the far western

, found in southwest

and in

as far south as the

Transverse Ranges The Transverse Ranges are a group of mountain ranges of southern California, in the Pacific Coast Ranges physiographic region in North America. The Transverse Ranges begin at the southern end of the California Coast Ranges and lie within Santa ...

and east in the

. It grows from sea level to elevations of .

Ecology

Tanoak is

shade tolerant In ecology, shade tolerance is a plant's ability to tolerate low light levels. The term is also used in horticulture and landscaping, although in this context its use is sometimes imprecise, especially in labeling of plants for sale in commercial ...

and benefits from disturbances. It is susceptible to wildfire, wounds from which are exploited by rot fungi. It one of the species most seriously affected by "sudden oak death" (''

Phytophthora ramorum ''Phytophthora ramorum'' is the oomycete (a type of protist) plant pathogen known to cause the disease sudden oak death (SOD). The disease kills oak and other species of trees and has had devastating effects on the oak populations in California ...

''), with high mortality reported over much of the species' range. Fine hairs on the young leaves and twigs discourage deer from eating them. Various animals, including

squirrel Squirrels are members of the family Sciuridae, a family that includes small or medium-size rodents. The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrels. ...

s, deer and bears, eat the nuts.

Uses

The nut kernel is very bitter, and is inedible for people without extensive leaching. Some California Native Americans prefer this nut to those of many oak acorns because it stores well due to the comparatively high

tannin Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids. The term ''tannin'' (from Anglo-Norman ''tanner'' ...

content. The Concow tribe call the nut hä’-hä ( Konkow language). The

Hupa Hupa ( Yurok language term: Huep'oola' / Huep'oolaa = "Hupa people") are a Native American people of the Athabaskan-speaking ethnolinguistic group in northwestern California. Their endonym is Natinixwe, also spelled Natinook-wa, meaning "Peopl ...

people use the acorns to make meal, from which they would make mush, bread, biscuits, pancakes, and cakes. They also roast the acorns and eat them. Roasted, the seeds can be used as a coffee substitute.Natural Medicinal Herbs
Reference page = Herb latin name: Lithocarpus pachyphylla
/ref> The name ''tanoak'' refers to its tannin-rich bark, a type of

tanbark Tanbark is the bark of certain species of trees, traditionally used for tanning hides into leather. The words "tannin", " tanning", " tan," and " tawny" are derived from the Medieval Latin ''tannare'', "to convert into leather." Bark mills a ...

, used in the past for tanning

leather Leather is a strong, flexible and durable material obtained from the tanning, or chemical treatment, of animal skins and hides to prevent decay. The most common leathers come from cattle, sheep, goats, equine animals, buffalo, pigs and hog ...

before the use of modern synthetic tannins. By 1907, the use of tanoak for tannin was subsiding due to the scarcity of large tanoak trees. There were not enough trees around for a worthwhile economic return. By the early 1960s, there were only a few natural tannin operations left in California. The industry was beginning to switch to a synthetic alternative. Tanoak tannin has been used as an astringent. A mulch made from the leaves of the plant can repel grubs and slugs. The wood is strong and sometimes used as lumber, but suitable trees are usually inaccessible. It is also used as firewood.

References

External links

* *
Interactive Distribution Map of ''Lithocarpus densiflorus''

{{Taxonbar, from1=Q17410244, from2=Q17271024 Fagaceae Monotypic Fagales genera Plants used in Native American cuisine Trees of the Southwestern United States Trees of the Northwestern United States Flora of California Flora of the Sierra Nevada (United States) Natural history of the California Coast Ranges