(DRAFT) - Taxonomy
Species BIRCH, VIRGINIA ROUND-LEAF
Species Id ESIS705002
Date 13 MAR 96
TAXONOMY
NAME - BIRCH, VIRGINIA ROUND-LEAF
OTHER COMMON NAMES - BIRCH, VIRGINIA ROUND-LEAF; BIRCH, ASHE;BIRCH, ASHE'S; BIRCH and VIRGINIA
ELEMENT CODE -
CATEGORY - Angiosperm
PHYLUM AND SUBPHYLUM - MAGNOLIOPHYTA,
CLASS AND SUBCLASS - MAGNOLIOPSIDA,
ORDER AND SUBORDER - FAGALES,
FAMILY AND SUBFAMILY - BETULACEAE,
GENUS AND SUBGENUS - BETULA,
SPECIES AND SSP - UBER,
SCIENTIFIC NAME - BETULA UBER
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Virginia Round-leaf Birch
Betula uber (Ashe) Fern.
KINGDOM: Plant GROUP: Angiosperm
DIVISION: Magnoliophyta CLASS: Magnoliopsida
ORDER: Fagales FAMILY: Betulaceae
Morphologically, Betula uber is characterized by suborbicular
leaves (01), 2.5-5.8 cm long (01,03) by 2.3-5.0 cm wide (03,04),
cordate at the base (01), rounded to very obtuse at the apex (03),
3-6 pairs of lateral veins (01,05), and 25-40 coarse serrations (04).
The fruiting catkins are 1.4-2.3 cm long (based on rachis length) (04)
and possess nearly glabrous, 4.8-6.0 mm long scales with broadly
divergent lateral lobes (04). The bark is dark brown to black, and
mostly smooth (01,04); the inner bark is highly aromatic with an
essence of wintergreen (01,03,04). Individuals possess a typical
tree-like form, and vary up to 14 m in height (01) and 20 cm in stem
diameter (at 1.4 m above the ground) (06). The crown is small and
compact, with numerous slender, spreading branches (01,04).
In his original description, Ashe (03) recognized the round-leaf
birch as a variety of the common sweet birch (B. lenta L.) because of
similarities in features of the bark and fruit. Fernald (05) later
Taxonomy - 1 (DRAFT) - Taxonomy
Species BIRCH, VIRGINIA ROUND-LEAF
Species Id ESIS705002
Date 13 MAR 96
examined Ashe's specimens and concluded they had little in common with
typical B. lenta, other than aromatic bark. He, therefore, raised
Ashe's var. uber to the rank of species and transferred it from the
dark-barked birches (series Costatae) to the shrub birches (series
Humiles), most of which possess small, suborbicular leaves. More
recent studies of the anatomy of wood favor the alignment of B. uber
with the dark-barked tree birches (07). Detailed quantitative studies
of the leaves and fruits suggest a closer affinity of B. uber to B.
lenta than to other North American dark-barked birches (04).
Resolution of the taxonomic status of B. uber awaits ongoing studies
of its biozsystematics (04).
The holotype for B. uber, originally sent to the National
Arboretum, is apparently lost (11). Thus Ashe's collection deposited
in the Arnold Arboretum and annotated by M.L. Fernald as the
isotype of B. uber, is considered the lectotype (11). Six additional
specimens, one each at the Arnold Arboretum, New York Botanical
Garden, U.S. National Arboretum, and Carnegie Museum, and two
specimens at the University of North Carolina at Chapel Hill are
designated as isolectotypes of the taxon (11). Specimens from more
recent collections are deposited at Virginia Polytechnic Institute and
State University, the National Arboretum, the Smithsonian, Radford
University, Emory and Henry College, the University of Tennessee,
Missouri Botanical Garden, Longwood College, and Virginia Highlands
Community College (04,06,22).
Taxonomy - 2 (DRAFT) - Status
Species BIRCH, VIRGINIA ROUND-LEAF
Species Id ESIS705002
Date 13 MAR 96
STATUS
Coded Status
Virginia; Federal Endangered
Virginia; State Listed
E: Federal Endangered
Commercial
Non-consumptive recreational
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The Virginia round-leaf birch (Betula uber) has been designated
an Endangered species pursuant to the Endangered Species Act of 1973
(50 CFR 17.12; P.L. 93-205, 87 Stat. 884; 16 U.S.C. 1531-1540),
as amended. The species has this status wherever found including the
State of Virginia.
Removal and reduction to possession of any Federally listed plant
from an area under Federal jurisdiction is unlawful (50 CFR 17.61 and
17.71).
RESPONSIBLE FEDERAL AGENCIES:
USFWS -Responsible for the management/recovery, listing, and
law enforcement/protection of this species.
USFS -Responsible for the law enforcement/protection of this
species with applicable State and Federal laws on
public lands under their control. Also responsible
for management/recovery on Forest Service lands. The
Forest Service is responsible for integrating
management, protection, and conservation of Federally
listed species into the Forest Planning process
(36 CFR 219.19 and 219.20).
The National Arboretum of USDA is responsible for propagation and
distribution of the trees to other arboreta, thus assuring some of
them survive if we lose the wild populations.
All Federal agencies have responsibility to ensure that any
action authorized, funded, or carried out by that agency is not likely
to jeopardize the continued existence of the species or result in the
destruction or adverse modification of Critical Habitat (50 CFR 402),
and to utilize their authorities to carry out programs for the
conservation of the species.
STATE STATUSES AND LAWS:
STATE: Virginia
DESIGNATED STATUS: Endangered
ADMINISTRATIVE AGENCY: Department of Agriculture and Consumer
Services.
STATE STATUTES: Endangered Plant and Insect Species Act,
Title 3.1, Chapter 39, Sections 3.1-1020 through
Status - 1 (DRAFT) - Status
Species BIRCH, VIRGINIA ROUND-LEAF
Species Id ESIS705002
Date 13 MAR 96
3.1-1030. Approved March 23, 1979.
Under the State law, the taking of state listed plants from other than
one's own land is prohibited, which provides an important measure of
protection not available under Federal law.
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
None.
ECONOMIC STATUSES:
This species is of interest to propagators who would like to sell
individual plants. It also has scientific and aesthetic value to man.
76/06/16:41 FR 27523/ - Proposed rule
78/04/26:43 FR 17910/17916 - Listed as Endangered
83/12/08:48 FR 55100/55102 - Five year review
85/07/22:50 FR 29900/29901 - Five year review completion
Status - 2 HABITAT ASSOCIATIONS
HABITAT - TERRESTRIAL
TERRESTRIAL
INLAND AQUATIC
SOCIETY OF AMERICAN FORESTRY TYPES
SAF TYPE STAGE CLOSURE
Shortleaf Pine-Oak shrub--seedling
Shortleaf Pine-Oak young tree
Shortleaf Pine-Oak mature tree
shrub--seedling
young tree
mature tree
shrub--seedling
young tree
mature tree
LAND USE -
Cropland and Pasture
Deciduous Forest Land
Mixed Forest Land
Streams and Canals
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Riverine, upper perennial
COMMENTS ON HABITAT ASSOCIATIONS -
The only existing natural population of Betula uber occurs along
the banks of the middle reaches of a small mountain stream, Cressy
Creek, at an elevation of 820 m (2700 ft). The climate is relatively
cool and moist, with a mean July temperature of 20.6 degrees C (69
degrees F) and mean annual precipitation of 1219 mm (48 in) (15).
The adult segment of the population is almost entirely within that
part of the floodplain which receives coarse alluvial deposits almost
annually (16). The part of the juvenile population originating prior
to 1975 (now 7 individuals) occurs on an artificially-created
(dike-like) mound of earth which once enclosed a tailings pond (16).
No individuals in the B. uber population are more than 30 m from the
present streambed of Cressy Creek.
Soils are entisols, classified locally as stony colluvium (17,
19,20). They are very flaggy, strongly acid, and exhibit rapid
permeability. Soil profiles generally consist of sandy loam material
with variable concentrations of gravels, cobbles, and boulders (19).
The rooting zone varies between 51 and 102 cm (17). Much of the
colluvial parent material is apparently derived from loamy, skeletal,
mixed mesic Typic Dystrochrepts of the Dekalb series, formed on the
steep side slopes adjoining the floodplain of Cressy Creek where the
bedrock consists of acid gray and brown sandstone and some interbedded
shale and graywacke stringers (17,19,20). In conclusion, soils
underlying the area of the B. uber population are droughty, and trees
occupying these sites probably exhibit high levels of moisture stress
during the growing season -- especially in years of low precipitation.
The continual influx of coarse alluvium appears to create an
especially droughty, exposed condition at the soil surface, which in
turn probably has a substantial effect on rates of germination and
Habitat Associations - 1 establishment of birch seedlings (16).
The vegetation which includes the adult segment of the Betula
uber population consists mainly of highly disturbed second-growth
forest, with the majority of the canopy trees less than 80 years old
(16). This forest occupies a corridor less than 100 m wide along
Cressy Creek. The potential vegetation appears to be transitional
between the oak-pine and maple-beech-birch associations, with some
tendencies toward the elm-ash-cottonwood association because of the
riparian setting (16,18). Tree species currently on the site, in
addition to Betula uber, include Acer rubrum L., A. saccharum Marsh.,
Amelanchier sp., Betula alleghaniensis Britt., B. lenta L., Carpinus
caroliniana Watt., Carya tomentosa (Poir.) Nutt., Cornus florida L.,
Fraxinus americana L., Liriodendron tulipifera L., Magnolia acuminata
L., M. fraseri Walt., Nyssa sylvatica Marsh., Pinus rigida Mill., P.
virginiana Mill., Platanus occidentalis L., Prunus serotina Ehrh.,
Quercus alba L., Q. prinus L., Q. rubra L., Robinia psuedoacacia L.,
and Tsuga canadensis (L.) Carr. Lesser woody vegetation consists of
Aristilochia durior Hill., Castanea pumila Mill., Crataegus punctata
Jacq., Hamamelis virginiana L., Hydrangea arborescens L., Lindera
benzoin (L.) Blume, Parthenocissus quiniquefolia (L.) Planch.,
Pyrularia pubera Michx., Rhododendron maximum L., Rhus glabra L.,
Rubus spp., Sambucus canadensis L., Smilax rotundifolia L., Viburnum
acerifolium Marsh., V. prunifolium L., and Vitis sp. (01).
The sites where the juvenile segments (seedlings and saplings) of
the Betula uber population occur are occupied by most of the same
species listed above (16). Of particular interest are comparisons
between the first-year vegetation in the two areas (1000 sq.m and 400
sq.m) cleared in late 1981 to secure natural regeneratin of B. uber,
and the adjacent second-growth forests (12). Between one-half and
two-thirds of the total tree regeneration in the clearings in the late
summer of 1982 consisted of birches (Betula alleghaniensis, B. lenta,
and B. uber), compared to a virtual absence of these species prior to
clearing and a significantly lower proportion in the surrounding
forest following clearing. Canopy cover (measured with a spherical
densiometer) in the cleared areas averaged 54 percent compared to 85
percent in the adjacent forested areas. Similar comparisons of a
number of other factors were: exposed mineral soil, 53% (percent)
vs. 13%; litter cover, 38% vs. 62%; ground vegetation (<1 m tall)
cover, 68% vs. 30%; and height of ground vegetation, 44 cm vs. 17 cm.
These values emphasize the dramatic shifts in the microhabitat
associated with clearing and the creation of regeneration niches for
B. uber.
Betula uber continues to be affected by the presence of actively
grazed pastureland in the Cressy Creek area, particularly along the
western and southern margins of the population where a considerable
extent of this land-use type falls within the seed shadow of fertile
individuals of B. uber. The nearly continuous ground cover, mostly of
grasses, appears to preclude establishment of seedlings, independent
of the effects of grazing itself (16).
Habitat Associations - 2 (DRAFT) - Food Habits
Species BIRCH, VIRGINIA ROUND-LEAF
Species Id ESIS705002
Date 13 MAR 96
FOOD HABITS
TROPHIC LEVEL -
AUTOTROPH
Food Habits - 1 (DRAFT) - Environment Associations
Species BIRCH, VIRGINIA ROUND-LEAF
Species Id ESIS705002
Date 13 MAR 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G
G
Environment Associations - 1 (DRAFT) - Life History
Species BIRCH, VIRGINIA ROUND-LEAF
Species Id ESIS705002
Date 13 MAR 96
LIFE HISTORY
HABIT:
Tree (01,03,04,06).
LIFE CYCLE:
Perennial (01,03,04,06,16). Reproductively mature individuals
dying between 1979 and 1983 ranged in age from 42 to 61 years and
averaged 50 years at the time of death (16). The oldest living
individual in the population was approximately 54 years of age in 1984
(16).
TYPE OF REPRODUCTION:
Sexual (12). Seed viability ranged from 6 to 52 percent and
averaged 26.5 percent, based on a sample of 6 fruiting trees of B.
uber in 1981. Comparable values, based on 4 fruiting trees of B.
lenta in the same area, were 50 to 90 percent and 71 percent (12).
REPRODUCTIVE PHENOLOGY:
Germination dates are not well known, but are believed to be
no earlier than early-mid June (16). Leafing out occurs late April to
early May (16). Budding dates are unknown. Anthesis dates are late
April (Julian day 118) - early May (Julian day 131) (16). Fruits
mature from mid-August through mid-October and seed is dispersed
between November and March, with the peak in January and February (13,
16).
SEX OR SPORE STATUS:
Monoecious (13).
POLLINATION, SPORE AND SEED DISSEMINATION:
Both pollen and seed are disseminated by wind (13). Differences
in wind speed and direction account for a substantial amount of the
variation in the temporal, directional, and distance components of
seed dispersal of B. uber (13). Most seed is dispersed to the east
and southeast of fruiting trees (13). The overall profile of
dispersal away from source trees is exponential, with nearly
two-thirds of the seeds falling within 30 m. A small (<5%) proportion
of seed is dispersed beyond 100 m (13).
SEED BIOLOGY:
Seed production in Betula uber varies greatly from year to year
and appears to be cyclic, with abundant fruits and seeds produced
every 3-4 years (16). Data collected on abundance of fruiting from
1978 through 1983 showed high yields in 1978, 1981, and 1984,
interspersed with years of moderate to low production. In good
fruiting years, seed density may exceed 40 per sq.m on the forest
floor within a hundred meters of a single fruiting tree, and more than
100 per sq.m within 40 m of the source (13). In 1981, seed viability
among six fruiting trees ranged from 6 - 52% and averaged 26.5 percent
(12). Under laboratory conditions, nearly all seeds which are viable
will germinate within one month of incubation following cold (5
degrees C), moist stratification for 30 days. However, in nature even
Life History - 1 (DRAFT) - Life History
Species BIRCH, VIRGINIA ROUND-LEAF
Species Id ESIS705002
Date 13 MAR 96
in good seed years and on recently exposed mineral soils with moderate
levels of incoming solar radiation (considered optimum for
germination), less than one seedling per sq.m survives to the end of
the first growing season (12).
POPULATION BIOLOGY:
When Betula uber was rediscovered in 1975, the only known natural
population consisted of about 40 individuals (14 adults and 26
seedlings/saplings), intermixed with individuals of a number of
hardwood and coniferous tree species over an area of approximately one
hectare (10,000 sq.m) (06). By 1977 this number dwindled to 20, and
by 1984 to 11 individuals (4 adults and 7 saplings) (06,16). Most of
the mortality in the subadult (i.e., pre-reproductive) segment of the
population was due to vandalism, while the bulk of the losses in the
adult segment can be attributed to natural forces (06,12,16).
Although flooding and probably drought were directly responsible for
some of the mortality in the adult plants, the ultimate cause of death
in the majority of individuals (which occurred between the ages of 40
and 60 years) was probably related to the ecological role of the
species as a short-lived, pioneer species which succumbs to
competition from later successional species (06,12,16). Thus, when
forested areas are heavily disturbed (i.e., canopy cover removed and
mineral soils exposed) within dispersal distance of fruiting trees,
natural regeneration is obtained. Such was the case in 1982 when 0.4
seedlings per sq.m appeared in a 400 sq.m forest opening created the
previous winter (12). A decrease from 80 to 30 seedlings in this
opening between 1982 and 1983 indicates that seedling mortality in the
species is high (16). Herbivory by white-tailed deer and rabbits,
although not causing direct mortality, may have rendered some
seedlings less competitive. Unfortunately, heavy vandalism between
late 1983 and early 1984, which resulted in the loss of 18 seedlings,
precluded an ongoing study of natural survival rates in the species.
B. uber is also limited by its breeding system and apparently
close evolutionary ties to the common sweet birch, B. lenta (04).
Open-pollinated seeds from B. uber mother trees exhibit significantly
lower germination rates than those from B. lenta mother trees (12),
and the resulting seedlings exhibit lower growth rates in cultivation
(16). The frequency of seedlings with round leaves (typical of B.
uber) produced by these same B. uber mother trees averaged only 1.2%,
with the remaining seedlings possessing leaves indistinguishable from
those of B. lenta (12). The frequency of round-leaved seedlings
produced by a B. uber mother tree is indirectly proportional to the
distance to the closest B. uber pollen source--the species being an
obligate out crosser (12). Ongoing studies are designed to test the
hypothesis that B. uber represents a Mendelian segregate in the B.
lenta population, originating through a local mutation (14).
Thus, the occurrence of B. uber in nature appears to be limited
by a number of factors, including an absence of disturbed forest
conditions in the immediate vicinity, vandalism, herbivory, a
breeding system which may be developmentally retarded and permits
heavy gene exchange with B. lenta, and by chance effects related to
the small size of the population. Nonetheless, ongoing efforts
suggest that through a planned program of forest disturbance and law
Life History - 2 (DRAFT) - Life History
Species BIRCH, VIRGINIA ROUND-LEAF
Species Id ESIS705002
Date 13 MAR 96
enforcement, B. uber will be able to maintain itself in the wild at
levels comparable to or higher than those existing in 1975 (14,16).
ECOLOGICAL/EDAPHIC FACTORS:
B. uber occurs on mesic sands and loams. The only existing
natural popultion occurs along the banks of the middle reaches of a
small mountain stream, Cressy Creek, at an elevation of 820 m (2700
ft). The climate is relatively cool and moist, with a mean July
temperature of 20.6 degrees C (69 degrees F) and mean annual
precipitation of 1219 mm (48 in) (15). The adult segment of the
population is almost entirely within that part of the floodplain which
receives coarse alluvial deposits almost annually (16). The part of
the juvenile population originating prior to 1975 (now 7 individuals)
occurs on an artificially-created (dike-like) mound of earth which
once enclosed a tailings pond (16). No individuals in the B. uber
population are more than 30 m from the present streambed of Cressy
Creek.
Soils are entisols, classified locally as stony colluvium (17,19,
20). They are very flaggy, strongly acid, and exhibit rapid
permeability. Soil profiles generally consist of sandy loam material
with variable concentrations of gravels, cobbles, and boulders (19).
The rooting zone varies between 51 and 102 cm (17). Much of the
colluvial parent material is apparently derived from loamy, skeletal,
mixed mesic Typic Dystrochrepts of the Dekalb series, formed on the
steep side slopes adjoining the floodplain of Cressy Creek (17,19,20)
where the bedrock consists of acid gray and brown sandstone and some
interbedded shale and graywacke stringers. In conclusion, soils
underlying the area of the B. uber population are droughty, and trees
occupying these sites probably exhibit high levels of moisture stress
during the growing season -- expecially in years of low precipitation.
The continual influx of coarse alluvium appears to create an
especially droughty, exposed condition at the soil surface, which in
turn probably has a substantial effect on rate of germination and
establishment of birch seedlings (16).
The sites where the juvenile segments (seedlings and saplings) of
the Betula uber population occur are occupied by most of the same
species that occur with the adult segment of the population (16) (See
COMMUNITY ECOLOGY section that follows). Of particular interest are
comparisons between the first-year vegetation in the two areas (1000
sq.m and 400 sq.m) cleared in late 1981 to secure natural regeneratin
of B. uber, and the adjacent second-growth forests (12). Between
one-half and two-thirds of the total tree regeneration in the
clearings in the late summer of 1982 consisted of birches (Betula
alleghaniensis, B. lenta, and B. uber), compared to a virtual absence
of these species prior to clearing and a significantly lower
proportion in the surrounding forest following clearing. Canopy cover
(measured with a spherical densiometer) in the cleared areas averaged
54 percent compared to 85 percent in the adjacent forested areas.
Similar comparisons of a number of other environmental factors were:
exposed mineral soil, 53% vs. 13%; litter cover, 38% vs. 62%; ground
vegetation (<1 m tall) cover, 68% vs. 30%; and height of ground
vegetation, 44 cm vs. 17 cm. These values emphasize the dramatic
shifts in the microhabitat associated with clearing and the creation
Life History - 3 (DRAFT) - Life History
Species BIRCH, VIRGINIA ROUND-LEAF
Species Id ESIS705002
Date 13 MAR 96
of regeneration niches for B. uber.
Betula uber continues to be affected by the presence of actively
grazed pastureland in the Cressy Creek area, particularly along the
western and southern margins of the population where a considerable
extent of this land-use type falls within the seed shadow of fertile
individuals of B. uber. The nearly continuous ground cover, mostly of
grasses, appears to preclude establishment of seedlings, independent
of the effects of grazing itself (16).
The above describes conditions where the species now occurs. It
provides limited insight into optimum conditions for establishment,
growth and maintenance of the species. However, the recent
establishment of additional populations of B. uber over a wide range
of site conditions in the Cressy Creek watershed should be of
considerable value in this regard (14,16).
TROPHIC STATUS:
Autotrophic, phototrophic (01,06).
CHARACTERISTIC DOMINANCE:
Dominant/codominant (01,06,13,16).
Following disturbance on certain sites, it appears that Betula
uber has the capacity to be a dominant or co-dominant (with B. lenta)
for perhaps 50-60 years (12,16). However, as a forest stand develops
beyond this point, long-lived and more shade tolerant tree species
apparently replace the birches. This seems to be the current
situation in the second-growth forest stand where B. uber occurs (16).
Since birch mortality here has been high in this stand over the past
eight years, it is now in transition from a situation where B. uber
would have been considered a dominant or co-dominant to one where it
is fast becoming a subdominant (16). The induced disturbance in 1981
has done much to reverse this trend (14).
COMMUNITY ECOLOGY:
The vegetation which includes the adult segment of the Betula
uber population consists mainly of highly disturbed second-growth
forest, with the majority of the canopy trees less than 80 years old
(16). This forest occupies a corridor less than 100 m wide along
Cressy Creek. The potential vegetation appears to be transitional
between the oak-pine and maple-beech-birch associations, with some
tendencies toward the elm-ash-cottonwood association because of the
riparian setting (16,18). Tree species currently on the site, in
addition to Betula uber, include Acer rubrum L., A. saccharum Marsh.,
Amelanchier sp., Betula alleghaniensis Britt., B. lenta L., Carpinus
caroliniana Watt., Carya tomentosa (Poir.) Nutt., Cornus florida L.,
Fraxinus americana L., Liriodendron tulipifera L., Magnolia acuminata
L., M. fraseri Walt., Nyssa sylvatica Marsh., Pinus rigida Mill., P.
virginiana Mill., Platanus occidentalis L., Prunus serotina Ehrh.,
Quercus alba L., Q. prinus L., Q. rubra L., Robinia psuedoacacia L.,
and Tsuga canadensis (L.) Carr. Lesser woody vegetation consists of
Aristilochia durior Hill., Castanea pumila Mill., Crataegus punctata
Jacq., Hamamelis virginiana L., Hydrangea arborescens L., Lindera
benzoin (L.) Blume, Parthenocissus quiniquefolia (L.) Planch.,
Pyrularia pubera Michx., Rhododendron maximum L., Rhus glabra L.,
Life History - 4 (DRAFT) - Life History
Species BIRCH, VIRGINIA ROUND-LEAF
Species Id ESIS705002
Date 13 MAR 96
Rubus spp., Sambucus canadensis L., Smilax rotundifolia L., Viburnum
acerifolium Marsh., V. prunifolium L., and Vitis sp. (01).
Temporally, the vegetation appears to be in transition from a
birch-dominated community to one dominated by longer-lived and more
shade tolerant tree species, including Acer rubrum, A. saccharum,
Fraxinus americana, Platanus occidentalis, Quercus rubra, Tilia
americana, and Tsuga canadensis (16). The recent, induced disturbance
in 1981 has tended to reverse this trend and increase dominance by
birches, including B. uber (12,16).
The relatively small size of the stand, surrounded by
agricultural and residential land, probably contributes to its
compositional instability and high diversity (16).
SPECIES INTERRELATIONSHIPS:
Betula uber appears to be very closely related to the common
sweet birch (B. lenta L.). Over 600 sweet birches were intermingled
with the 40 individuals of B. uber in the Cressy Creek area (06).
Morphologically, the two taxa are separated only on the basis of leaf
attributes and to a lesser extent, overall form. Unlike most birches,
they cannot be distinguished with certainty on the basis of fruit and
seed characteristics (04). The two taxa overlap in time of flowering
and are apparently interfertile. In one field trial, only 1.2% of the
progeny of six B. uber mother trees possessed round leaves; the
remainder had leaves indistinguishable from those of B. lenta (12).
Few had leaves intermediate between the two taxa. These observations
have led biologists to hypothesize that B. uber originated as a local
mutation in the B. lenta population; and that the round-leaf form of
B. uber is controlled by a single, recessive gene which expresses
itself only in the homozygous condition (12). Controlled crosses
involving the two taxa are currently underway to test this hypothesis
(14).
OTHER LIFE HISTORY DESCRIPTORS:
None.
Life History - 5 (DRAFT) - Management Practices
Species BIRCH, VIRGINIA ROUND-LEAF
Species Id ESIS705002
Date 13 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Controlling/Restricting Road Maintainance Actions
Beneficial Land Acquisition
Beneficial Controlling/Restricting Herbicide Use
Beneficial Reforestation
Beneficial Maintaining Early Stages of Succession
Beneficial Controlling/Removing Native Vegetation
Beneficial Maintaining Sperm/Seed Banks
Beneficial Stocking captive-reared wild-strain animals
Beneficial Disease Control Measures
Beneficial Restricting Poaching
Beneficial Controlling/Removing Native Vertebrates
Beneficial Controlling/Removing Domestic Animals
Adverse Incidental Capturing/Killing
Existing Incidental Capturing/Killing
Adverse Harassment/Vandalism/Indiscriminate Killing
Existing Harassment/Vandalism/Indiscriminate Killing
Adverse Collecting
Existing Collecting
Adverse Inherent Reproductive Characteristics
Existing Inherent Reproductive Characteristics
Adverse Low Gene Pool
Existing Low Gene Pool
Adverse Hybridization
Existing Hybridization
Adverse Predation
Existing Predation
Adverse Rural Residential/Industrial Areas
Existing Rural Residential/Industrial Areas
Adverse Highway/Railroads
Existing Highway/Railroads
Adverse Transmission Lines/Towers
Existing Transmission Lines/Towers
Adverse Flooding
Existing Flooding
Adverse Competition
Existing Competition
Adverse Erosion
Existing Erosion
Adverse Grazing
Existing Grazing
Adverse
Existing
Adverse Vegetation Composition Changes
Existing Vegetation Composition Changes
COMMENTS ON MANAGEMENT PRACTICES -
Betula uber has apparently always been rare (06). This means
that chance events are likely to have a large impact on the size of
Management Practices - 1 (DRAFT) - Management Practices
Species BIRCH, VIRGINIA ROUND-LEAF
Species Id ESIS705002
Date 13 MAR 96
the single existing population, and in the extreme case, could cause
its extinction from the wild. B. uber is an early successional
(pioneer) species that seemingly relies on periodic disturbance to
maintain its numbers (06,12). When this disturbance is lacking
within effective seed dispersal distance of fruiting trees (13), these
trees do not replace themselves. As a matter of normal successional
events, B. uber is eventually supplanted by species which are better
competitors under relatively undisturbed conditions. Thus it appears
that the normal processes operating on a relatively short-lived
pioneer species of limited distribution account for a substantial
part of the reduction of B. uber in the wild, from 40 individuals (14
adults, 26 seedlings/saplings) in 1975 to 15 individuals (8 adults, 7
seedlings/saplings) in the fall of 1981 (12). Only 11 (4 adults, 7
seedlings/saplings) of the original 40 individuals remained alive in
the fall of 1984. As B. uber requires moist, exposed mineral soils
and moderate levels of incoming solar radiation to regenerate itself,
the maintenance of closed forest canopies in the immediate vicinity of
fruiting trees and of pasture-land and rural residences beyond largely
precludes the recruitment of individuals to the population (06,12).
Not until disturbance was induced adjacent to fruiting trees by
biologists in late 1981 was there any increase in the size of the
population, which now stands at 23 (4 adults, 19 seedlings/saplings).
Periodic flooding along Cressy Creek has adverse effects on the
Betula uber population, both directly and indirectly. One adult (in
1977) and several one-year-old seedlings (in 1983) growing along the
banks of the creek were lost when high water washed away the
underlying substrate (06,16). Continual deposition of coarse alluvium
over the soil surface creates a droughty condition, which may
adversely affect both the growth and survival of adults, and the
germination and extablishment of seedlings (16).
The impacts of grazing on the Betula uber population are
difficult to assess. Prior to its rediscovery in 1975, most of the
population was exposed to grazing and browsing by domestic livestock
and wildlife (chiefly deer and rabbits). By 1977, most of the area
had been surrounded by fence; only the private tract containing most
of the adult trees remained accessible to native browsers (06). Of
the 30 two-year-old seedlings existing in the fall of 1983, four
showed evidence of browsing by deer (16). Six of the 30 seedlings
were subsequently clipped back to ground level, apparently by rabbits,
in the winter of 1983; all resprouted the following growing season.
Vandalism and collection for scientific purposes are responsible
for the loss of 10 of the original 40 individuals in the population
(06), while vandalism alone accounts for an additional loss of 18
seedlings originating from the planned disturbance in 1981 (14). One
of the private landowners transplanted 3 seedlings on his property
from their natural habitat to his yard, pointing out the weakness of
existing state and federal legislation as it does not prohibit such
actions involving endangered plants (06). One of the trees on Forest
Service land was cut back to near ground level during normal
maintenance of a transmission corridor prior to any knowledge that B.
uber occurred in the area (06). Likewise, routine road maintenance
may have accounted for the loss of several additional seedlings (06).
Finally, inherent reproductive characteristics must be considered
Management Practices - 2 (DRAFT) - Management Practices
Species BIRCH, VIRGINIA ROUND-LEAF
Species Id ESIS705002
Date 13 MAR 96
as offering some threat to the natural population (12). Recent
studies have shown that seed viability is significantly lower in
Betula uber than in other native birches (B. lenta and B.
alleghaniensis) in the Cressy Creek area, and that B. uber does not
reproduce its own kind with as high a frequency as do the other
birches (12). The latter situation is probably due both to the high
degree of isolation of fertile trees (which are obligate outcrossers)
and to the swamping of B. uber pollen by other birches (especially B.
lenta) which are of much higher density in the area and are
interfertile with B. uber.
Nearly all the above factors continue to offer some threat to the
native Betula uber population.
APPROVED PLAN:
U.S. Fish and Wildlife Service. 1986. Virginia Round-leaf Birch
Recovery Plan. U.S. Fish & Wildlife Service, Newton Corner, MA.
28 pp.
The Virginia Round-leaf Birch Recovery Plan (approved March
1986) recommends (among other items) the following recovery actions:
1) Erect a fence around the portion of the population within Forest
Service lands to protect the species from vandalism.
2) Implement erosion control techniques (e.g., replacement of riprap
and water control bars).
3) Professional plant pathologists and entomologists should annually
assess the tree's status and make recommendations for corrective
action.
4) The purchase of appropriate and available private property should
be considered.
5) Use captive propagation and reintroduction of cultivated seedlings
to establish new populations. Protect newly planted seedlings from
deer browsing by encircling the seedlings with wire cages.
6) Encourage natural regeneration by removing competitive native
vegetation and preparing appropriate areas for revegetation by B. uber
seedlings.
7) Establish pollen and seed banks.
8) Conduct studies on the reproductive and genetic systems of B. uber
and closely related taxa.
9) Gain the cooperation of appropriate public agencies whose actions
may effect the species (e.g., individuals of this species near
right-of-ways may be effected by herbicide use or road maintenance
actions).
Ongoing recovery activities include habitat acquisition by The
Nature Conservancy, site preparation and planting by the U.S. Forest
Service (USFS), and continuing propagation and biological studies by
U.S.Fish & Wildlife Service (USFWS). Law enforcement protection is
provided both by the USFWS and the Virginia Department of Agriculture.
Management Practices - 3 (DRAFT) - References
Species BIRCH, VIRGINIA ROUND-LEAF
Species Id ESIS705002
Date 13 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 Ogle, D. W. and P. M. Mazzeo. 1976. Betula uber, the Virginia
round-leaf birch, rediscovered in Southwest Virginia. Castanea 41:
248-256.
02 Cronquist, A. 1968. The evolution and classification of flowering
plants. Houghton Mifflin Co.: Boston.
03 Ashe, W. W. 1918. Notes on Betula. Rhodora 20:63-64.
04 Sharik, T. L. and R. H. Ford. 1984. Variation and taxonomy of
Betula uber, B. lenta, and B. alleghaniensis. Brittonia 36(3):307-
316.
05 Fernald, M. L. 1945. Notes on Betula in eastern North America.
Rhodora 47:303-328.
06 Sharik, T. L. 1980. The endangered Virginia round-leaf birch
(Betula uber (Ashe) Fernald): A challenge to the management of
rare and local tree populations. Pages 67-77. In: Feret, P.P. and
T.L. Sharik (eds.). Proc. Conf. Dendrology in the Eastern
Deciduous Forest Biome. Va. Polytech. Inst. & St. Univ.,
Blacksburg, VA. Sept. 11-13, 1979. VPI & SU School For. Wildl.
Resour. Publ. FWS-2-80.
07 Hayden, W. J. and S. M. Hayden. 1984. Wood anatomy and
relationships Betula uber. Castanea 49:26-30.
08 Little, E. L. 1953. Checklist of the native and naturalized trees
of the United States. USDA For. Serv. Agric. Handb. 41., U.S.
Govt. Printing Office: Wash., D.C.
09 Johnson, A. G. 1954. Betula lenta var. uber Ashe. Rhodora 56:
129-131.
10 Petrides, G. A. 1972. A field guide to trees and shrubs, 2nd ed.
Houghton Mifflin Co.: Boston.
11 Mazzeo, P. M. 1974. Betula uber -- what is it and where is it?
Castanea 39:273-278.
12 Sharik, T. L. and D. M. Porter. 1983. The current status of the
Virginia round-leaf birch, Betula uber (Ashe) Fernald. Annual
Progress Report submitted to Office Endangered Species, U.S. Fish
Wildl. Serv., Region 5, Newton Corner, Mass., August 1983.
13 Ford, R. H., T. L. Sharik, and P. P. Feret. 1983. Seed dispersal
of the Endangered Virginia round-leaf birch (Betula uber). For.
Ecol. Manage. 6:115-128.
14 Sharik, T. L. 1984. Minutes to the Betula uber Protection,
Management and Research Co-ordinating Committee meeting, May 31,
1984. (Available from Ranger, Mt. Rogers National Recreation Area,
Rt. 1, Box 303, Marion, VA. 24354).
15 Rice, K. A. 1959. Climates of the states: Virginia. U.S. Dept.
Commerce, Weather Bureau. Climatography of the United States No.
60-44. U.S. Govt. Printing Office: Wash., D.C.
16 Sharik, T. L., Dept. Biology, Va. Polytech. Inst. & St. Univ.,
Blacksburg. Personal observations (including unpublished data) and
conversations with numerous persons between 1976 and 1984.
17 Patterson, W. Soil Conservation Service, Smyth Co., VA. As cited
In: 01.
18 Garrison, G. A., A. J. Bjugstad, D. A. Duncan, M. E. Lewis, and D.
References - 1 (DRAFT) - References
Species BIRCH, VIRGINIA ROUND-LEAF
Species Id ESIS705002
Date 13 MAR 96
R. Smith. 1977. Vegetation and environmental features of forest
and range ecosystems. USDA For. Serv. Agric. Handb. 475. U.S.
Govt. Printing Office: Wash., D.C.
19 Lietzke, D. A. and A. C. Porter. 1978. Interpretive guide to the
soils of Southwest Virginia TVA counties. Extension Div., Va.
Polytech. Inst. & St. Univ., Blacksburg.
20 Lietzke, D. A. Undated. Guide to soil taxonomy and key to
Virginia soils, Appalachian Division. Report MA-219. Extension
Div., Va. Polytech. Inst. & St. Univ., Blacksburg.
21 Ogle, D. W. 1975. Betula uber found. Castanea 40:365.
22 Ogle, D. W. 1984. Virginia Highlands Community College, Abingdon.
Personal written communication with T. L. Sharik, Sept. 25, 1984.
***** REFERENCES FOR N-OCCURRENCE NARATIVE ONLY *****
01 Sharik, T. L. 1980. The Endangered Virginia round-leaf birch
(Betula uber (Ashe) Fernald): A challenge to the management of
rare and local tree populations. Pages 67-77. In: P.P. Feret and
T.L. Sharik (eds.). Proc. Conf. Dendrology in the Eastern
Deciduous Forest Biome. Va. Polytechnic Inst. & St. Univ.,
Blacksburg, VA, Sept. 11-13, 1979. VPI & SU School of Forestry and
Wildlife Resources Publ. FWS-2-80.
02 Ford, R. H., T. L. Sharik and P. P. Feret. 1983. Seed dispersal
of the Endangered Virginia round-leaf birch (Betula uber). For.
Ecol. Manage. 6:115-128.
03 Ogle, D. W. and P. W. Mazzeo. 1976. Betula uber, The Virginia
round-leaf birch, rediscovered in Southwest Virginia. Castanea 41:
248-256.
04 Bailey, R. G. and C. T. Cushwa (Compilers). 1982. Ecoregion
surface form and hydrologic unit maps of the United States.
U.S. Fish Wildl. Serv., Biologic. Serv. Prog. FWS/OBS-82/09.
05 Ashe, W. W. 1918. Notes on Betula. Rhodora 20:63-64.
06 Sharik, T. L. and R. H. Ford. 1984. Variation and taxonomy of
Betula uber, B. lenta, and B. alleghaniensis. Brittonia 36(3):
In Press.
07 U.S. Fish and Wildlife Service. 1982. Virginia round-leaf birch
Recovery Plan. U.S. Fish & Wildlife Service Special Report.
Region 5. 66 pp.
08 Sharik, T. L. 1984. Minutes to the Betula uber Protection,
Management and Research Co-ordinating Committee Meeting, May 31,
1984. (Available from Ranger, Mt. Rogers National Recreational
Area, Jefferson NF, Route 1, Box 303, Marion, VA 24354).
References - 2