A native broadleaved tree with excellent timber properties that is an important host for many species of flora and fauna and consequently of high ecological value. There are currently approximately 151,000 ha of ash in Britain accounting for 11% of all broadleaved woodland (IFOS).
Ash has been under severe threat from the disease Chalara ash dieback (Hymenoscyphus fraxineus).
Ash dieback is a highly destructive disease of ash trees (Fraxinus species), especially the United Kingdom’s native ash species, Common Ash Fraxinus excelsior L. It is caused by a fungus named Hymenoscyphus fraxineus (H. fraxineus), which is of eastern Asian origin.
The disease is also known as "Chalara", ash dieback, and Chalara dieback of ash. Calling it "Chalara" ash dieback helps to distinguish it from dieback on ash trees caused by other agents.
Spread over longer distances is most likely to be through the movement of diseased ash plants. There has, up to very recently been a prohibition on importation and inland movements of ash seeds, plants or other planting material. This prohibition of inland movements has now been lifted across Great Britain.
Chalara is now well established and widely distributed, being present in every county. As such, there is no technical case and no purpose to retaining national measures against ash dieback. There is much more benefit to be gained from lifting the restrictions, so that tolerant ash trees can be bred, moved and planted.
Our Cornish Trebrown Nurseries' seed stands contain both trees which were infected and trees that have remained totally unaffected by the disease, thus the unaffected trees are considered tolerant ash trees. We are now resuming seed-collections from these tolerant trees and growing them on in our nursery. We will now get our ash stands re-certified for FRM nationwide, and you can order ash trees for planting the same as any other forest tree.
Ash is a native tree and categorised as a principal tree species. These are tree species where silvicultural knowledge provides confidence to enable successful deployment across Britain. The species are either already widely used or are increasing in usage. They will continue to be important unless affected by a new pest or disease or become adversely affected by climate change.
Native to the British Isles and much of western Europe except the far north. Material from good quality British stands should be preferred with provenances in northern France as an alternative in southern Britain. When available resilient genotypes.
Ash has intermediate shade tolerance when young, but needs early thinning for good growth. The species is cold hardy and moderately tolerant of exposure, but is susceptible to late frost damage which can cause forking. This is a very site demanding species. Grows best on moist, well-drained deep and rich soils with a high nitrogen content, and often overlying calcareous bedrock; requires pH values of five or above. Nutrient poor dry and waterlogged soils should be avoided.
Management should be to select the most appropriate silvicultural system that allows for identification and long-term retention of visually healthy trees. This activity of favouring trees demonstrating tolerance of the disease may enhance recruitment of potential resilient seedlings during regeneration. Practices such as coppicing are not recommended.
