Ian Wright, gardens adviser and plant health specialist at the National Trust said: “We are extremely concerned about the potential risk to our UK ash caused by the suspected cases of this disease on trees within the native tree population.
“Although no suspected cases have to date been discovered on National Trust land, we had already issued guidance to our teams when we heard of the outbreak in imported trees in other parts of the country earlier in the year. The guidance included precautions such as holding off from planting any new ash trees, putting any recently bought ornamental or native trees into quarantine and ensuring good hygiene practices to minimise the risk of contamination.
“Our outdoor teams are also monitoring all our ash trees on a regular basis. We will wait for more information to emerge from this rapidly changing situation and will be in close contact with the Forestry Commission and FERA. We will also be following any guidance and updates from them to help slow the spread of this virulent disease.
All press interested in interviewing Ian Wright should contact the press office on 0844 800 4955.
1. In the early 1990s severe dieback of ash (Fraxinus excelsior) was noted in north-eastern Poland. Trees of all ages were affected and typically displayed small necrotic patches on their stems and branches which later developed into girdling lesions resulting in wilting of leaves, tip dieback of branches and mortality of trees. Initially, the cause(s) of the dieback were unclear but a species of Chalara was frequently isolated from lesions on symptomatic trees and by the mid-2000s this was recognised as both a new fungal species Chalara fraxinea and as the primary pathogen involved in the causation of ash dieback.
2. Ash (Fraxinus excelsior) in Britain is the third most commonly recorded broadleaved species highlighted in the most recent Census of Woodlands and Trees, and is the second most widely planted broadleaved tree. Ash is found on a huge variety of site types, calcareous/acid, lowland/upland and throughout the UK. Ash is an important tree in terms of its timber value and a key component of many habitats and feature of most landscapes. It is also thought that ash will become a much more extensive and important element of many existing woods as it regenerates profusely and does not appear to suffer serious bark stripping by grey squirrels as do many other native broadleaved species. Because of these valuable characteristics, existing beech woodlands, PAWS restoration areas and even oak woods are likely to become more dependant on ash to survive as healthy and productive broadleaved woodlands
3. Since the early 2000s, Chalara fraxinea has spread rapidly across continental Europe with ash dieback now reported from the majority of European countries. During 2012 interceptions of ash saplings infected with C. fraxinea, were found both in a number of key UK nurseries and shortly after out-planting. The outbreaks/original infection might have occurred as far back as 2009
4. Despite the detection of ash dieback in out-planted ash saplings, the pest is not yet considered to be established in the natural environment in the UK, since the infected plants are likely to have harboured the disease prior to planting and there is currently no evidence to indicate that transmission to other trees has occurred. However, the rapid establishment of the pest throughout many European countries, and the existence of appropriate growth conditions for the pest suggest that in the UK the potential for establishment is high and therefore the risk very high.
5. The National Trust looks after 25,000 hectares of woodland and forest.