Quercus havardii
Encyclopedia
Quercus havardii is a deciduous, low-growing, thicket-forming shrub that occupies some 2 to 3 million ha in the southern Great Plains
of North America
. Clones may reach hundreds to thousands of years old, although aboveground stems typically live only 11 to 15 years. Shinnery oak stems are usually 1-2 m tall and codominate the plant community with mid- and tall-grasses which are usually taller than the oaks.
The specific epithet honors U.S. Army surgeon and botanist Valery Havard
, who contributed much to the knowledge of southwestern plants. The word "shinnery" seems to be derived from chêne (French for oak), and not from the height of the plant.
s through the sandy soil where it is usually found. Rhizomes range from 3-15 cm in diameter and are concentrated in upper 60 cm of soil, although penetration depths of 9 m has been reported. Lateral roots and woody rhizomes are widespread near the soil surface. Ninety percent or more of shinnery oak's biomass is under ground, and fortuitous root grafting is common. These underground stems commonly spread to form plants 3 to 15 m or more in diameter. Single clones are reported to cover up to 81 ha and to achieve ages over 13,000 years.
Flowers: Shinnery oak is monoecious with both female and male flowers borne separately on the same plant. Male catkins are densely flowered, 1.5-3.8 cm long, and hang downward. Female catkins are 3-7 mm long, contain 1 to 5 flowers, and are usually axillary on young shoots. Shinnery oaks are wind pollinated, and flowering occurs in the spring.
Acorns: Acorns develop in 1 year, maturing in the autumn. Acorns occur alone or in clusters of 2 or 3, and are 12-25 mm long by 14-18 mm wide. A scaly cup covers about 1/3 to 1/2 of the nut. On average, acorn crops are produced in 3 out of 10 years.
Foliage: The leathery, highly variable leaves are grey green to olive green, have a lustrous upper surface, and are whitish and densely hairy below. Leaves are alternate, simple, with variable shape
(oblong, ovate, or elliptical), and with wavy or shallowly lobed margins. Length is 2 to 8 cm and width 2 to 4 cm.
Twigs: Twigs are brown or grayish, 1-2.5 mm diameter, glabrous or densely covered with short grayish or yellowish hairs, that are lost with age. Buds are dark red-brown, somewhat spherical, about 2 mm long, and sparsely pubescent.
Bark: Bark on the larger stems is light gray and scaly.
of shinnery oak with Gambel oak (Quercus gambelii) and perhaps shrub live oak (Quercus turbinella
) make taxonomic identification of these populations difficult.
Shinnery oak hybridizes with Mohr oak (Quercus mohriana
) and post oak (Quercus stellata). Post oak x shinnery oak hybrids are likely to be a result of post oak's historic range, which extended more westerly than it does today. Mohr oak x shinnery oak hybrids are restricted to habitats intermediate to those occupied by the two species. Mohr oak inhabits limestone soils, and shinnery oak occurs on deep sand soils.
, west Texas
, eastern New Mexico
, and 2 isolated populations in southwest Kansas
. A variety also occurs in northeastern Arizona
and southeastern Utah
. Sandy plains, sand dunes, and sand hills of the southern Great Plains are typical habitat.
overwinter in the oak litter and infest nearby cotton fields in spring. Thus, most research and other human effort concerning shinnery oak have been devoted to its eradication.
The use of chemical and mechanical control methods has been extensive, making it likely that shinnery oak's distribution is decreasing. Most authorities do not recommend complete eradication of shinnery oak, indicating that forage production is typically greater if some shinnery oak remains in the community. Stocking rates and rotational grazing patterns exist that reduce the incidence of shinnery oak poisoning of cattle. Excessive control of shinnery oak is controversial because it can open sandy soils to wind erosion and can conflict with wildlife-habitat quality.
Shinnery oak sprouts prolifically from rhizomes soon after fire. Researchers described the communities as "extremely fire hardy".
, lesser prairie-chicken
s, northern bobwhites, and many other wildlife species eat shinnery oak acorns. Deer
, pronghorn
, and southern plains woodrats browse shinnery oak. Shinnery oak habitats are used by black-tailed jackrabbit
s, desert cottontail
s, eastern cottontail
s, wild turkey
s, western box turtles, a diversity of arthropods, approximately 25 snake
species, and approximately 10 lizard
species, including the endangered sand dune lizard (Sceloporus arenicolus
).
Many game species also rely on shinnery oak. Scaled quail
and northern bobwhites use shinnery oak habitats extensively, and shinnery oak habitats are considered "the principal home for white-tailed deer in the southern Great Plains".
Shinnery oak provides rich habitat for wildlife compared with the surrounding shortgrass plains
. Maintaining wildlife habitat and improving vegetation for livestock grazing are often in conflict, and should be carefully considered before undertaking control of shinnery oak.
Great Plains
The Great Plains are a broad expanse of flat land, much of it covered in prairie, steppe and grassland, which lies west of the Mississippi River and east of the Rocky Mountains in the United States and Canada. This area covers parts of the U.S...
of North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
. Clones may reach hundreds to thousands of years old, although aboveground stems typically live only 11 to 15 years. Shinnery oak stems are usually 1-2 m tall and codominate the plant community with mid- and tall-grasses which are usually taller than the oaks.
The specific epithet honors U.S. Army surgeon and botanist Valery Havard
Valery Havard
Valery Havard , was a career army officer, physician , author, and botanist. Although he held many notable posts during his military career, he is most well known for his service on the western frontier of the United States and in Cuba...
, who contributed much to the knowledge of southwestern plants. The word "shinnery" seems to be derived from chêne (French for oak), and not from the height of the plant.
Description
Form: A low shrub to 2 m or occasionally a small tree, Q. havardii forms large clonal thickets by extending rhizomeRhizome
In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...
s through the sandy soil where it is usually found. Rhizomes range from 3-15 cm in diameter and are concentrated in upper 60 cm of soil, although penetration depths of 9 m has been reported. Lateral roots and woody rhizomes are widespread near the soil surface. Ninety percent or more of shinnery oak's biomass is under ground, and fortuitous root grafting is common. These underground stems commonly spread to form plants 3 to 15 m or more in diameter. Single clones are reported to cover up to 81 ha and to achieve ages over 13,000 years.
Flowers: Shinnery oak is monoecious with both female and male flowers borne separately on the same plant. Male catkins are densely flowered, 1.5-3.8 cm long, and hang downward. Female catkins are 3-7 mm long, contain 1 to 5 flowers, and are usually axillary on young shoots. Shinnery oaks are wind pollinated, and flowering occurs in the spring.
Acorns: Acorns develop in 1 year, maturing in the autumn. Acorns occur alone or in clusters of 2 or 3, and are 12-25 mm long by 14-18 mm wide. A scaly cup covers about 1/3 to 1/2 of the nut. On average, acorn crops are produced in 3 out of 10 years.
Foliage: The leathery, highly variable leaves are grey green to olive green, have a lustrous upper surface, and are whitish and densely hairy below. Leaves are alternate, simple, with variable shape
Leaf shape
In botany, leaf shape is characterised with the following terms :* Acicular : Slender and pointed, needle-like* Acuminate : Tapering to a long point...
(oblong, ovate, or elliptical), and with wavy or shallowly lobed margins. Length is 2 to 8 cm and width 2 to 4 cm.
Twigs: Twigs are brown or grayish, 1-2.5 mm diameter, glabrous or densely covered with short grayish or yellowish hairs, that are lost with age. Buds are dark red-brown, somewhat spherical, about 2 mm long, and sparsely pubescent.
Bark: Bark on the larger stems is light gray and scaly.
Taxonomy
Shinnery oak populations in Utah and Arizona are considered a variety of shinnery oak (Quercus havardii var. tuckeri) by some taxonomist. However, introgressionIntrogression
Introgression, also known as introgressive hybridization, in genetics is the movement of a gene from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species...
of shinnery oak with Gambel oak (Quercus gambelii) and perhaps shrub live oak (Quercus turbinella
Quercus turbinella
Quercus turbinella is a species of oak known by the common names Sonoran scrub oak and shrub live oak. It is native to northwestern Mexico and the southwestern United States from far eastern California to southwest Colorado, Rio Grande New Mexico, to west Texas.-Distribution:Quercus turbinella...
) make taxonomic identification of these populations difficult.
Shinnery oak hybridizes with Mohr oak (Quercus mohriana
Quercus mohriana
thumb|left|Typical oak savannaQuercus mohriana, commonly known as the Mohr oak, shin oak or scrub oak, is an evergreen shrub or small tree in the white oak group and is endemic to the south central montane regions of North America...
) and post oak (Quercus stellata). Post oak x shinnery oak hybrids are likely to be a result of post oak's historic range, which extended more westerly than it does today. Mohr oak x shinnery oak hybrids are restricted to habitats intermediate to those occupied by the two species. Mohr oak inhabits limestone soils, and shinnery oak occurs on deep sand soils.
Native range
Shinnery oak is native to western OklahomaOklahoma
Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...
, west Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
, eastern New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
, and 2 isolated populations in southwest Kansas
Kansas
Kansas is a US state located in the Midwestern United States. It is named after the Kansas River which flows through it, which in turn was named after the Kansa Native American tribe, which inhabited the area. The tribe's name is often said to mean "people of the wind" or "people of the south...
. A variety also occurs in northeastern Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...
and southeastern Utah
Utah
Utah is a state in the Western United States. It was the 45th state to join the Union, on January 4, 1896. Approximately 80% of Utah's 2,763,885 people live along the Wasatch Front, centering on Salt Lake City. This leaves vast expanses of the state nearly uninhabited, making the population the...
. Sandy plains, sand dunes, and sand hills of the southern Great Plains are typical habitat.
Management
A majority of shinnery oak occurs on private land used for agriculture and/or livestock production. It is considered undesirable on grazing lands, because it competes with better livestock forage and its buds and leaves are toxic to cattle for several weeks in spring. In addition, where cotton is grown near shinnery oak, boll weevilsBoll weevil
The boll weevil is a beetle measuring an average length of six millimeters, which feeds on cotton buds and flowers. Thought to be native to Central America, it migrated into the United States from Mexico in the late 19th century and had infested all U.S. cotton-growing areas by the 1920s,...
overwinter in the oak litter and infest nearby cotton fields in spring. Thus, most research and other human effort concerning shinnery oak have been devoted to its eradication.
The use of chemical and mechanical control methods has been extensive, making it likely that shinnery oak's distribution is decreasing. Most authorities do not recommend complete eradication of shinnery oak, indicating that forage production is typically greater if some shinnery oak remains in the community. Stocking rates and rotational grazing patterns exist that reduce the incidence of shinnery oak poisoning of cattle. Excessive control of shinnery oak is controversial because it can open sandy soils to wind erosion and can conflict with wildlife-habitat quality.
Shinnery oak sprouts prolifically from rhizomes soon after fire. Researchers described the communities as "extremely fire hardy".
Uses
Because shinnery oak thrives in a harsh environment, it functions as a sand dune stabilizer, protecting sandy soils from wind erosion. It also provides diverse wildlife species cover and food. Collared peccariesCollared Peccary
The collared peccary is a species of mammal in the family Tayassuidae that is found in North, Central, and South America. They are commonly referred to as javelina, saíno or báquiro, although these terms are also used to describe other species in the family...
, lesser prairie-chicken
Lesser Prairie Chicken
The Lesser Prairie Chicken, Tympanuchus pallidicinctus, a species in the grouse family, is slightly smaller and paler than its near relative the Greater Prairie Chicken...
s, northern bobwhites, and many other wildlife species eat shinnery oak acorns. Deer
White-tailed Deer
The white-tailed deer , also known as the Virginia deer or simply as the whitetail, is a medium-sized deer native to the United States , Canada, Mexico, Central America, and South America as far south as Peru...
, pronghorn
Pronghorn
The pronghorn is a species of artiodactyl mammal endemic to interior western and central North America. Though not an antelope, it is often known colloquially in North America as the prong buck, pronghorn antelope, or simply antelope, as it closely resembles the true antelopes of the Old World and...
, and southern plains woodrats browse shinnery oak. Shinnery oak habitats are used by black-tailed jackrabbit
Black-tailed Jackrabbit
The black-tailed jackrabbit , also known as the american desert hare, is a common hare of the western United States and Mexico, where it is found at elevations from sea level to up to...
s, desert cottontail
Desert Cottontail
The Desert Cottontail , also known as Audubon's Cottontail, is a New World cottontail rabbit, a member of the family Leporidae....
s, eastern cottontail
Eastern Cottontail
The eastern cottontail is a New World cottontail rabbit, a member of the family Leporidae. It is one of the most common rabbit species in North America.-Distribution:...
s, wild turkey
Wild Turkey
The Wild Turkey is native to North America and is the heaviest member of the Galliformes. It is the same species as the domestic turkey, which derives from the South Mexican subspecies of wild turkey .Adult wild turkeys have long reddish-yellow to grayish-green...
s, western box turtles, a diversity of arthropods, approximately 25 snake
Snake
Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...
species, and approximately 10 lizard
Lizard
Lizards are a widespread group of squamate reptiles, with nearly 3800 species, ranging across all continents except Antarctica as well as most oceanic island chains...
species, including the endangered sand dune lizard (Sceloporus arenicolus
Sceloporus arenicolus
The dunes sagebrush lizard, Sceloporus arenicolus, , is an insectivorous spiny lizard species which only occurs in the shinnery oak sand dune systems of extreme southeast New Mexico and only four counties in adjacent Texas...
).
Many game species also rely on shinnery oak. Scaled quail
Scaled Quail
The Scaled Quail , also commonly called Blue Quail or cottontop, is a species of the New World quail family. It is a bluish gray bird found in the arid regions of the Southwestern United States to Central Mexico...
and northern bobwhites use shinnery oak habitats extensively, and shinnery oak habitats are considered "the principal home for white-tailed deer in the southern Great Plains".
Shinnery oak provides rich habitat for wildlife compared with the surrounding shortgrass plains
Shortgrass prairie
The shortgrass prairie ecosystem of the North American Great Plains is a prairie that includes lands from the eastern foothills of the Rocky Mountains east to Nebraska and Saskatchewan, including rangelands in Alberta, Wyoming, Montana, North, South Dakota, and Kansas, and extending to the south...
. Maintaining wildlife habitat and improving vegetation for livestock grazing are often in conflict, and should be carefully considered before undertaking control of shinnery oak.