Betula uber
Encyclopedia
Betula uber is a rare species of tree
in the birch family
. One of the most endangered species
of North American trees, it is endemic to Smyth County, in the U.S. state
of Virginia
. It is part of the temperate broadleaf and mixed forests
biome
.
The tree was first described in 1918 as a variety of Betula lenta, and elevated to species status in 1945. It hybridizes with B. lenta and it has been suggested that it is actually a round-leaved mutant form of that species. Some authorities prefer to treat it as a variety.
After it was first discovered, the tree was not seen again and was thought to be extinct
until 1975, when some individuals were located. These 18 adult trees and 23 saplings and seedling
s were in a forest along the degraded banks of Cressy Creek in Smyth County, Virginia. The tree was federally listed as an endangered species
and conservation
efforts were begun. Many seedlings were sprouted in greenhouse
s and planted in the forest. By 1995 there were 20 populations and it was downlisted to threatened status. The tree was propagated in order to discourage collectors from taking wild specimens, or vandals
from destroying them. A recent count estimated 961 individuals in the wild as of 2006. Eight of these are in the original creekside population. The species will not be removed from the endangered species
list yet because it has not been observed reproducing sexually
, and naturally, more than once. The expansion of its range is limited because the area is surrounded by agricultural land
, but the territory on which the tree occurs is not immediately threatened.
This is a tree of moderate size, growing up to 15 meters tall. The crown
is compact. The bark is aromatic and dark brown or black in color. The leaf is round or slightly oval with a heart-shaped base and a toothed edge and measures up to 5 centimeters long. The catkin
is up to 2.8 centimeters long and contains tiny samaras
measuring 2 millimeters in length. The tree is wind-pollinated
and reproduces by seed
. Seed production is much heavier in some years than in others. The tree's lifespan is around 50 years.
Tree
A tree is a perennial woody plant. It is most often defined as a woody plant that has many secondary branches supported clear of the ground on a single main stem or trunk with clear apical dominance. A minimum height specification at maturity is cited by some authors, varying from 3 m to...
in the birch family
Betulaceae
Betulaceae, or the Birch Family, includes six genera of deciduous nut-bearing trees and shrubs, including the birches, alders, hazels, hornbeams and hop-hornbeams, numbering about 130 species...
. One of the most endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
of North American trees, it is endemic to Smyth County, in the U.S. state
U.S. state
A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...
of Virginia
Virginia
The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
. It is part of the temperate broadleaf and mixed forests
Temperate broadleaf and mixed forests
Mixed forests are a temperate and humid biome. The typical structure of these forests includes four layers. The uppermost layer is the canopy composed of tall mature trees ranging from 33 to 66 m high. Below the canopy is the three-layered, shade-tolerant understory that is roughly 9 to...
biome
Biome
Biomes are climatically and geographically defined as similar climatic conditions on the Earth, such as communities of plants, animals, and soil organisms, and are often referred to as ecosystems. Some parts of the earth have more or less the same kind of abiotic and biotic factors spread over a...
.
After it was first discovered, the tree was not seen again and was thought to be extinct
Extinction
In biology and ecology, extinction is the end of an organism or of a group of organisms , normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point...
until 1975, when some individuals were located. These 18 adult trees and 23 saplings and seedling
Seedling
thumb|Monocot and dicot seedlingsA seedling is a young plant sporophyte developing out of a plant embryo from a seed. Seedling development starts with germination of the seed. A typical young seedling consists of three main parts: the radicle , the hypocotyl , and the cotyledons...
s were in a forest along the degraded banks of Cressy Creek in Smyth County, Virginia. The tree was federally listed as an endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
and conservation
Habitat conservation
Habitat conservation is a land management practice that seeks to conserve, protect and restore, habitat areas for wild plants and animals, especially conservation reliant species, and prevent their extinction, fragmentation or reduction in range...
efforts were begun. Many seedlings were sprouted in greenhouse
Greenhouse
A greenhouse is a building in which plants are grown. These structures range in size from small sheds to very large buildings...
s and planted in the forest. By 1995 there were 20 populations and it was downlisted to threatened status. The tree was propagated in order to discourage collectors from taking wild specimens, or vandals
Vandalism
Vandalism is the behaviour attributed originally to the Vandals, by the Romans, in respect of culture: ruthless destruction or spoiling of anything beautiful or venerable...
from destroying them. A recent count estimated 961 individuals in the wild as of 2006. Eight of these are in the original creekside population. The species will not be removed from the endangered species
Endangered Species Act
The Endangered Species Act of 1973 is one of the dozens of United States environmental laws passed in the 1970s. Signed into law by President Richard Nixon on December 28, 1973, it was designed to protect critically imperiled species from extinction as a "consequence of economic growth and...
list yet because it has not been observed reproducing sexually
Sexual reproduction
Sexual reproduction is the creation of a new organism by combining the genetic material of two organisms. There are two main processes during sexual reproduction; they are: meiosis, involving the halving of the number of chromosomes; and fertilization, involving the fusion of two gametes and the...
, and naturally, more than once. The expansion of its range is limited because the area is surrounded by agricultural land
Agriculture
Agriculture is the cultivation of animals, plants, fungi and other life forms for food, fiber, and other products used to sustain life. Agriculture was the key implement in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that nurtured the...
, but the territory on which the tree occurs is not immediately threatened.
This is a tree of moderate size, growing up to 15 meters tall. The crown
Crown (botany)
The crown of a plant refers to the totality of the plant's aboveground parts, including stems, leaves, and reproductive structures. A plant canopy consists of one or more plant crowns growing in a given area....
is compact. The bark is aromatic and dark brown or black in color. The leaf is round or slightly oval with a heart-shaped base and a toothed edge and measures up to 5 centimeters long. The catkin
Catkin
A catkin or ament is a slim, cylindrical flower cluster, with inconspicuous or no petals, usually wind-pollinated but sometimes insect pollinated . They contain many, usually unisexual flowers, arranged closely along a central stem which is often drooping...
is up to 2.8 centimeters long and contains tiny samaras
Samara (fruit)
A samara is a type of fruit in which a flattened wing of fibrous, papery tissue develops from the ovary wall. A samara is a simple dry fruit and indehiscent . It is a winged achene...
measuring 2 millimeters in length. The tree is wind-pollinated
Anemophily
Anemophily or wind pollination is a form of pollination whereby pollen is distributed by wind. Anemophilous plants may be either gymnosperms or angiosperms ....
and reproduces by seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
. Seed production is much heavier in some years than in others. The tree's lifespan is around 50 years.
External links
- World Conservation Monitoring Centre 1998. Betula uber. 2006 IUCN Red List of Threatened Species. Downloaded on 20 August 2007.
- USDA Plants Profile