Betula Chichibuensis - Version 2014.3. Shaw, K., Roy, S., & Wilson, B. In The IUCN Red List of Threatened Species, pages 194282/0+. 2014.
abstract   bibtex   
[Excerpt] The species is very rare in the wild, and was reported to be reduced to 21 trees in the wild in 1993 (McAllister 1993). Although no recent survey data provide updated population information, it is unlikely that remaining population exceeds 50 mature individuals. It has no close living relatives anywhere else in the world and it is therefore probably of very ancient origin.~This species is known only from a single location at Mt Kamo-san, near Tano-Gun, in Gumna prefecture. It has a very small extent of occurrence and area of occupancy, both below the thresholds for being considered Critically Endangered under criterion B. The small population and restricted distribution of~B. chichibuensis~make it susceptible to natural disasters or disease and it occurs at one threat-based location. The species is also self-incompatible, requiring two individuals to be close enough to cross-pollinate one another, making seed production uncertain in small subpopulations. Wild collected seed has also shown low viability. These factors potentially threaten the survival of this species. Deforestation and habitat degradation are also evident in the Chichibu District, presenting a threat to the survival of this species. [::Common Name(s)] [::]English - Chichibu Birch [::Range Description] Endemic to Japan,~this species~is confined to the Chichibu area in the mountains of Central Honshu on Mt Kamo-san, near Tano-Gun, in Gunma prefecture. As restricted to Mt Kamo-san, the~extent of occurrence and area of occupancy are therefore estimated to be under thresholds for being considered Critically Endangered. [::Countries] Native:Japan (Honshu) [::Population] The species~exists as small subpopulations and is very rare. Twenty-one known individuals were reported in 1993 (McAllister 1993).~Although no recent survey data provide updated population information, it is unlikely that remaining population exceeds 50 mature individuals.~It has no close living relatives anywhere else in the world and it is therefore probably of very ancient origin.~Although the sprouting habit of this species enables individuals to be very long-lived, it is self-incompatible so the need for two individuals to survive close enough together to cross-pollinate one another could make the production of seed uncertain in small subpopulations.~The very low viability (less than one percent) of the wild collected seed from Japan suggests little viable seed production in the wild and therefore a low chance of natural regeneration. [::Habitat and Ecology] Betula chichibuensis forms a multi-stemmed shrub or small tree to 10 m high. This species grows in limestone outcrops. Although young immature plants appear to be relatively shade tolerant, mature trees are very intolerant of shade. The species also appears to be fairly tolerant of wet soils and is relatively drought tolerant, at least once established. The bark is initially brown and flaky but later develops conspicuous raised horizontal lenticels. It has papery ovate leaves, glabrous and green on the upper surface with white hairs on the underside, deeply veined. This species is monoecious with catkin-like creamy yellow male and catkin-like red female inflorescences. The fruiting catkins bear tiny nutlet fruits. This species flowers from May to June.\textasciitilde [::Use and Trade] There is no use or trade information available for this species. [::Major Threat(s)] The small population and restricted distribution of B. chichibuensis~make it susceptible to natural disasters or disease. The species is also self-incompatible, requiring two individuals to be close enough to cross-pollinate one another, making seed production uncertain in small subpopulations. Wild collected seed has also shown low viability. These factors potentially threaten the survival of this species. Deforestation and habitat degradation are evident in the Chichibu District.
@incollection{shawBetulaChichibuensisVersion2014,
  title = {Betula Chichibuensis - {{Version}} 2014.3},
  booktitle = {The {{IUCN Red List}} of {{Threatened Species}}},
  author = {Shaw, K. and Roy, S. and Wilson, B.},
  year = {2014},
  pages = {194282/0+},
  abstract = {[Excerpt] The species is very rare in the wild, and was reported to be reduced to 21 trees in the wild in 1993 (McAllister 1993). Although no recent survey data provide updated population information, it is unlikely that remaining population exceeds 50 mature individuals. It has no close living relatives anywhere else in the world and it is therefore probably of very ancient origin.~This species is known only from a single location at Mt Kamo-san, near Tano-Gun, in Gumna prefecture. It has a very small extent of occurrence and area of occupancy, both below the thresholds for being considered Critically Endangered under criterion B. The small population and restricted distribution of~B. chichibuensis~make it susceptible to natural disasters or disease and it occurs at one threat-based location. The species is also self-incompatible, requiring two individuals to be close enough to cross-pollinate one another, making seed production uncertain in small subpopulations. Wild collected seed has also shown low viability. These factors potentially threaten the survival of this species. Deforestation and habitat degradation are also evident in the Chichibu District, presenting a threat to the survival of this species. [::Common Name(s)] [::]English - Chichibu Birch [::Range Description] Endemic to Japan,~this species~is confined to the Chichibu area in the mountains of Central Honshu on Mt Kamo-san, near Tano-Gun, in Gunma prefecture. As restricted to Mt Kamo-san, the~extent of occurrence and area of occupancy are therefore estimated to be under thresholds for being considered Critically Endangered. [::Countries] Native:Japan (Honshu) [::Population] The species~exists as small subpopulations and is very rare. Twenty-one known individuals were reported in 1993 (McAllister 1993).~Although no recent survey data provide updated population information, it is unlikely that remaining population exceeds 50 mature individuals.~It has no close living relatives anywhere else in the world and it is therefore probably of very ancient origin.~Although the sprouting habit of this species enables individuals to be very long-lived, it is self-incompatible so the need for two individuals to survive close enough together to cross-pollinate one another could make the production of seed uncertain in small subpopulations.~The very low viability (less than one percent) of the wild collected seed from Japan suggests little viable seed production in the wild and therefore a low chance of natural regeneration. [::Habitat and Ecology] Betula chichibuensis forms a multi-stemmed shrub or small tree to 10 m high. This species grows in limestone outcrops. Although young immature plants appear to be relatively shade tolerant, mature trees are very intolerant of shade. The species also appears to be fairly tolerant of wet soils and is relatively drought tolerant, at least once established. The bark is initially brown and flaky but later develops conspicuous raised horizontal lenticels. It has papery ovate leaves, glabrous and green on the upper surface with white hairs on the underside, deeply veined. This species is monoecious with catkin-like creamy yellow male and catkin-like red female inflorescences. The fruiting catkins bear tiny nutlet fruits. This species flowers from May to June.\textasciitilde{} [::Use and Trade] There is no use or trade information available for this species. [::Major Threat(s)] The small population and restricted distribution of B. chichibuensis~make it susceptible to natural disasters or disease. The species is also self-incompatible, requiring two individuals to be close enough to cross-pollinate one another, making seed production uncertain in small subpopulations. Wild collected seed has also shown low viability. These factors potentially threaten the survival of this species. Deforestation and habitat degradation are evident in the Chichibu District.},
  keywords = {*imported-from-citeulike-INRMM,~INRMM-MiD:c-13621313,betula-chichibuensis,conservation,forest-resources,iucn,iucn-critically-endangered-cr},
  lccn = {INRMM-MiD:c-13621313}
}

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