CPC Plant Profile: Virginia Roundleaf Birch
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Plant Profile

Virginia Roundleaf Birch (Betula uber)

Betula Uber habitat Photo Credit: Johnny Randall
Description
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: Federally Threatened
  • Family: Betulaceae
  • State: VA
  • Nature Serve ID: 157815
  • Date Inducted in National Collection: 12/01/2021

Betula uber is known from a single population in southwest Virginia. It was first reported in 1918, but the taxon was not seen again until 1975 when a single population of approximately 40 trees was rediscovered. It was originally described as a variety of B. lenta by Ashe in1918 and elevated to a full species by Fernald in 1945. Betula uber was formally listed as endangered in 1978, but was downlisted to threatened in 1995 after 20 additional populations were established. Although very similar to the widespread black or sweet birch (Betula lenta), it differs primarily in growth habit and having blunt or rounded leaves.

Updates
  • 09/01/2020
  • Propagation Research

And given that mechanical disturbance by removing leaf litter during a mast year in 1981 facilitated the germination of 82 seedlings, attention should be paid to assisted disturbance when a mast year is apparent. This management approach should be done in the natural population in addition to as many of the 20 planted populations as possible. Prescribed disturbance should also be a management priority since B. uber is probably a relatively short lived tree based on the life history of B. lenta.

  • 09/01/2020
  • Genetic Research

Because the systematics of B. uber remains unresolved, additional genetic analysis in addition to further controlled breeding experiments are warranted. Preliminary results from Shariks (1984) cross-pollination study between B. uber and B. lenta indicate that the round-leaf character may segregate (in Mendelian fashion) as a homozygous recessive trait. Arthur Cronquist visited the B. uber population in 1988 and suggested that the taxon may not be more than a form or B. lenta (J. Randall, pers. comm.). There are, however, morphological and chemical characters that support maintaining B. uber as a distinct species. Additional studies will, however, unlikely unravel if the single existing natural population of B. uber is the last or first of its kind. According to Sharik (1990) mast years and natural disturbance do not tend to coincide with B. uber.

  • 09/01/2020
  • Orthodox Seed Banking

According to the National Plant Germplasm System there are three accessions at the North Central Regional Plant Introduction Station in Ames, Iowa, and one accession at National Arboretum. These accessions date back to 1990, and there is no indication that these have been checked for viability. Given that the current ex situ collections are nearly 20 years old, re-collection and storage are recommended. The 1985 recovery plan indicates that ex situ seed collections are not a priority and are unnecessary because of the 20 established populations. The author of this profile believes that ex situ seed collections is a priority, particularly for the single natural population.

  • 09/01/2020
  • Orthodox Seed Banking

According to the National Plant Germplasm System there are three accessions at the North Central Regional Plant Introduction Station in Ames, Iowa, and one accession at National Arboretum. These accessions date back to 1990, and there is no indication that these have been checked for viability. Given that the current ex situ collections are nearly 20 years old, re-collection and storage are recommended. The 1985 recovery plan indicates that ex situ seed collections are not a priority and are unnecessary because of the 20 established populations. The author of this profile believes that ex situ seed collections is a priority, particularly for the single natural population.

  • 08/30/2020
  • Conservation Grove

Since 1975 the number of trees in the one natural population steadily declined to only 11 individuals in 1984. In response to this and the fact of only one population, twenty populations were created on Forest service lands using nursery-grown seedlings. Although vandalism initially threatened the seedling recovery program, the total current population is now over 961 trees. To date, however, none of the populations seem to be expanding

Nature Serve Biotics
  • 05/02/2017

First noticed in 1918, this taxon was not seen again until 1975 when the single population (then consisting of 41 trees) was rediscovered in Smyth County, Virginia. Since that time, the number of individuals in the natural, native population has steadily declined from eleven in 1984 to eight in 2003. In the early 1980's an aggressive recovery plan, involving planting greenhouse-grown seedlings at various sites, was implemented. Although vandalism initially threatened the recovery program, in 2003 there were 953 planted individuals alive. Whether these trees will be capable of competing and reproducing successfully remains to be seen. Lack of natural reproduction is a major threat.

Johnny Randall
  • 01/01/2010

A primary threat is that B. uber has only one natural population, although 20 additional populations have been established on Forest Service lands. The original population has three contiguous ownerships that include the U.S. Forest Service (Mount Rogers

Johnny Randall
  • 01/01/2010

Since 1975 the number of trees in the one natural population steadily declined to only 11 individuals in 1984. In response to this and the fact of only one population, twenty populations were created on Forest service lands using nursery-grown seedlings. Although vandalism initially threatened the seedling recovery program, the total current population is now over 961 trees. To date, however, none of the populations seem to be expanding.

Johnny Randall
  • 01/01/2010

There does not seem to be any current research on B. uber.

Johnny Randall
  • 01/01/2010

Management of B. uber does not appear to be an ongoing priority according to the 5-year recovery plan review (Davis 2006).

Johnny Randall
  • 01/01/2010

Because the systematics of B. uber remains unresolved, additional genetic analysis in addition to further controlled breeding experiments are warranted. Preliminary results from Shariks (1984) cross-pollination study between B. uber and B. lenta indicate that the round-leaf character may segregate (in Mendelian fashion) as a homozygous recessive trait. Arthur Cronquist visited the B. uber population in 1988 and suggested that the taxon may not be more than a form or B. lenta (J. Randall, pers. comm.). There are, however, morphological and chemical characters that support maintaining B. uber as a distinct species. Additional studies will, however, unlikely unravel if the single existing natural population of B. uber is the last or first of its kind. According to Sharik (1990) mast years and natural disturbance do not tend to coincide with B. uber. And given that mechanical disturbance by removing leaf litter during a mast year in 1981 facilitated the germination of 82 seedlings, attention should be paid to assisted disturbance when a mast year is apparent. This management approach should be done in the natural population in addition to as many of the 20 planted populations as possible. Prescribed disturbance should also be a management priority since B. uber is probably a relatively short lived tree based on the life history of B. lenta.

Johnny Randall
  • 01/01/2010

According to the National Plant Germplasm System there are three accessions at the North Central Regional Plant Introduction Station in Ames, Iowa, and one accession at National Arboretum. These accessions date back to 1990, and there is no indication that these have been checked for viability. Given that the current ex situ collections are nearly 20 years old, re-collection and storage are recommended. The 1985 recovery plan indicates that ex situ seed collections are not a priority and are unnecessary because of the 20 established populations. The author of this profile believes that ex situ seed collections is a priority, particularly for the single natural population.

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Photos
Nomenclature
Taxon Betula uber
Authority (Ashe) Fernald
Family Betulaceae
CPC Number 558
ITIS 19502
USDA BEUB
Common Names Virginia Round-leaf Birch | Virginia Roundleaf Birch | Virginia Birch
Associated Scientific Names Betula uber | Betula lenta var. uber | Betula lenta ssp. uber
Distribution Betula uber is restricted to a single population in Smyth County, Virginia.
State Rank
State State Rank
Virginia S1
Habitat

The only known natural population occurs at 1160 m elevation along a 700 m stretch of highly disturbed, second-growth forest less than 100 m wide along the banks of Cressy Creek, in Smyth County, Virginia (Sharik 1985). The band of forest is nearly surrounded by agricultural land.

Ecological Relationships

Betula uber seems to have the same ecological relationships as its close relative, B. lenta (sweet birch), whose habitat is moist, protected northerly or easterly slopes on well-drained soils, but is also found on a variety of less favorable sites with rocky coarse-textured or shallow soils. Typically associated species include: yellow-poplar (Liriodendron tulipifera), basswood (Tilia spp.), white ash (Fraxinus americana), sugar maple (Acer saccharum), red maple (A. rubrum), northern red oak (Quercus rubra), eastern hemlock (Tsuga canadensis), eastern white pine (Pinus strobus), mountain maple (Acer spicatum), striped maple (A. pensylvanicum), flowering dogwood (Cornus florida), downy serviceberry (Amelanchier arborea), American hornbeam (Carpinus caroliniana), eastern hophornbeam (Ostrya virginiana, Solomons-seal (Polygonatum pubescens), marsh blue violet (Viola cucullata), clubmosses (Lycopodium spp.), mayapple (Podophyllum peltatum), and trilliums (Trillium spp.).

Pollinators
Common Name Name in Text Association Type Source InteractionID

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