There is no doubt that C. fraxinea’s introduction and spread has been due to the global plant trade. Millions of native tree and shrub species have been imported into Britain over the past 30 years, and planted in farm hedges, to replant woods and create new ones. Over a decade ago, members of the Horticultural Trades Association Tree Seed and Nursery Group and Flora locale were jointly lobbying for this to stop.

It has also become apparent that much of the ash imported was grown from British-collected seed, subsequently sent to the Netherlands for propagation, then returned as saplings to British nurseries. This aspect of the plant trade has clearly been instrumental in facilitating the spread of C. fraxinea. As a result of the import of this disease, nurseries are now facing huge costs associated with destroying their ash stock.

Fortunately, our native ash is genetically diverse and regenerates very easily from seed. Flora locale agrees with the Botanical Society of the British Isles, that its genetic diversity should protect wild populations. In Denmark, 90% of trees have been affected and in Britain, millions of trees will die, but disease-resistant trees will survive and regenerate naturally. This is another reason why it is madness to import what may be less genetically and maladapted ash (or indeed any other native species) ecotypes of Continental European origin. It would be equally mad to breed “disease-resistant” varieties and for these selectively-bred, genetically uniform, varieties to be widely introduced.

Research and practical projects (that Flora locale has showcased) have also demonstrated that tree seeding is just as effective as tree planting, with the added benefit that some natural selection will take place to weed out individual trees that are unfit to the planted environment. It has been a great disappointment that this approach has not been taken on board by government agencies and those major charities that undertake tree planting and woodland creation. Advice on methods using tree seed are available in Flora locale’s practice note on Creating Woodlands Naturally. 

http://www.floralocale.org/Ash+news

 

 

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