Betula chichibuensis

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.

This species has been cultivated and when several clones are grown close together in cultivation the seed viability is high. In 1986 seeds were collected from trees growing on Mount Kamo-san and sent to Ness Botanic Gardens, University of Liverpool, UK. Some of the seeds were sown and others retained in case of failure. Eight clones from the original seed are now in cultivation and have been distributed as rooted cuttings taken from the original seedlings or viable seed to arboreta and botanic gardens in Europe and North America. Seedlings from the original wild-collected seed showed considerable variability in habit characteristics and most have flowered and fruited freely. As this species is easily propagated by cuttings, it is possible for commercial reproduction to occur from a single plant, and for one, self-incompatible clone to dominate the cultivated market of this species in the future. Care should be taken to maintain genetic diversity of this species.Both in situ and ex situ conservation are recommended for this species. Further field survey is recommended to determine population number and propagation material should be collected from as many remaining individuals as possible. This species was listed as Rare in Japan in the 1997 IUCN Red List of Threatened Plants. It is assessed as Endangered in the Red List of Threatened Plants of Japan.