Bleeding canker of horse chestnut: Horse Chestnut Trees
Overview of horse chestnut trees in Britain
Bleeding canker is a serious disease that is increasing in incidence in the UK. The disease affects horse chestnut trees (Aesculus hippocastanum).
Population in Britain
The National Woodland Inventory of Woodland Trees estimates there are 470,000 horse chestnut trees in Great Britain:
- England: 432,000
- Scotland: 29,100
- Wales: 11,100.
However, most of these trees are situated in non-woodland sites. Horse chestnut is only a significant component of British woodland (defined for this purpose as areas over 2 hectares) in a few cases - 51 hectares in England and 25 hectares in Wales (none in Scotland).
Most of the horse chestnuts in Britain are probably not accounted for in any national tree census, but are common along streets, in parks and gardens as amenity trees. Both planted and self-sown individual trees also flourish along roadsides and in hedges.
Horse chestnuts are able to tolerate a wide range of conditions including dry sandy soils, wet clays and chalk, but prefers moist, well-drained soils.
The horse chestnut is particularly prized as an amenity tree because of its striking flowers, which can be seen in early June each year, and its characteristic conker fruits that are produced in September.
Using horse chestnut
The wood of horse chestnut tends to be rather weak and for this reason has never been widely used. However it has absorbent properties that make it ideal for fruit racks and storage trays that keep the fruit dry and so prevent rotting.
Various extracts from horse chestnut leaves and fruits contain the active ingredients aescin or aesculin and are marketed as herbal remedies because of their anti-inflammatory properties.
Horse chestnut also has wildlife value: the nuts provide food for deer and other mammals and the flowers provide pollen for insects.
Apart from the horse chestnut which is the only Aesculus species native to Europe, there are twelve other species of Hipposcastanum that are found throughout the northern hemisphere, mainly in eastern Asia and eastern USA. There is also a single species native to western North America and another native to northwestern Mexico (Hardin, 1960).
|Species of Hippocastanum||Common name||Native Range|
|A. hippocastanum||Horse chestnut||Bulgaria, N. Greece, S. Albania|
|A. x carnea||Red horse chestnut||Hybrids between A. hippocastanum and A. parva|
|A. turbinata||Japanese horse chestnut||Japan|
|A. californica||Buckeye||California, United States|
|A. parryi||Parry buckeye||California, Mexico|
|A. flava||Sweet or yellow buckeye||South east United States|
|A. glabra||Ohio buckeye||South east United States|
|A. parvia||Red buckeye||South east United States|
|A. parviflora||Dwarf buckeye||South east United States|
|A. sylvatica||South east United States|
|A. assamica||N. Siam, NW Indo-China, s. China, NE Pakistan, Bhutan|
|A. indica||Indian horse chestnut||NW Himalayas|
|A. chinensis||Chinese horse chestnut||China|
|A. wilsonii||Wilson's horse chestnut||Central China|
Table compiled from: Bean (1925) and Forest et al. (2001).