''Notholithocarpus densiflorus'', commonly known as the tanoak or tanbark-oak, is a
broadleaf tree in the family
Fagaceae, 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 specime ...
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 primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
, particularly
Oregon
Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idaho. T ...
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.
P ...
, though is more usual,
and can have a trunk diameter of . The
bark is fissured, and ranges from gray to brown.
The
leaves 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 angiospe ...
is an
acorn long and 2 cm in diameter, very similar to an
oak
An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...
acorn, but with a very hard, woody nut shell more like a
hazel 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) 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 soils.
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'', where it was previously placed), but instead is an example of
convergent morphological evolution.
While related to oaks (as well as
chestnuts), the name is written as 'tanoak' because it is not a true oak.
Distribution
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 primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...
, found in southwest
Oregon
Oregon () is a state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington, while the Snake River delineates much of its eastern boundary with Idaho. T ...
and in
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 ...
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
Sierra Nevada. 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
squirrels, deer and bears, eat the nuts.
Uses
The nut kernel is very bitter, and is inedible for people without extensive
leaching
Leaching is the loss or extraction of certain materials from a carrier into a liquid (usually, but not always a solvent). and may refer to:
* Leaching (agriculture), the loss of water-soluble plant nutrients from the soil; or applying a small amou ...
. 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 Konkow language, also known as Northwest Maidu (also ''Concow-Maidu'', or ' in the language itself) is a part of the Maiduan language group. It is spoken in California. It is severely endangered, with three remaining elders who learned to s ...
). The
Hupa 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, used in the past for tanning
Tanning may refer to:
*Tanning (leather), treating animal skins to produce leather
*Sun tanning, using the sun to darken pale skin
**Indoor tanning, the use of artificial light in place of the sun
**Sunless tanning, application of a stain or dye t ...
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