Plant 295

Betula medwediewii (Betulaceae)

Transcaucasian birch

One hundred and two species of Betula, distributed across the northern hemisphere, are recognised in the World Checklist of Fagales. Native to the Caucasus at sub-alpine elevations, Betula medwediewii ranges from south-western Georgia and, in the provinces of Rize and Artvin, to north-eastern Turkey. It is considered rare across its range, especially in Georgia where populations are very small and fragmented. Its occurrence is uncertain in Azerbaijan, Armenia and Iran. The species grows on the upper margins of Picea orientalis forests, and is often accompanied by such rarities as Epigaea gaultherioides, Quercus pontica and Rhododendron ungernii. In Georgia it is found on open hillside, with sporadic Fagus orientalis, Picea orientalis, Sorbus graeca and Rhododendron luteum.

Introduced in 1897, Betula medwediewii is occasionally grown in arboreta and a few large gardens. Birches, in particular those with white bark, are one of the most popular groups of trees, valued for their elegance of habit, the variation and colours of their bark and leaves, their usually rapid growth and relatively small size. Betula medwediewii is distinguished form all other birches by its characteristic thick, stiff twigs with large, ovate to circular leaves. Large, upright, persistent fruiting catkins with brown scales also make this species stand out from other birches. A notable characteristic of Betula medwediewii is when the young bark and twigs are bruised, they have a sweet, aromatic taste and smell, which, by distillation, yields an aromatic oil.

A large, spreading shrub in cultivation to about three metres in height and almost twice that across. When grown on a single stem, this birch forms a goblet-shaped small tree. Irrespective of form, it develops the most sumptuous and beautiful golden yellow autumn colour, and the leaves remain on the tree for some time. Birches are generally very tolerant of most soil conditions, growing on a range of substrates where there is adequate moisture.

Assessed as Near Threatened in the Red List of Betulaceae, Betula medwediewii is under pressure mainly as a result of local grazing. This birch species is very slow-growing, so grazing of apical growth by both wild and domesticated animals inhibits the plant's ability to flower and produce seed. With the fruiting bodies being located near the growing tips, grazing by livestock has had a significant impact on this species' ability to reproduce naturally. Moreover, it is unlikely that the fragile seed can withstand animal digestive acids and pass out intact.

Further reading

Bean WJ 1976. Trees and shrubs hardy in the British Isles. John Murray.

Shaw K et al. 2014. Betula chichibuensis. The IUCN Red List of Threatened Species 2014: e.T194282A2309490.

Ben Jones