You may have read one of my earlier blogs about Ash Dieback –Chalara fraxinea which first came to light in late 2014 at a very low level, but I am saddened to read that it is now spreading rapidly across the UK. It is now in the West Midlands, an area in which there is 101,000 hectares of woodland and Ash makes up about 10% of the woodland cover and tends to occur in ash dominant woodlands so, Chalara could have significant impacts.
The disease is caused by a fungus and the symptoms include leaf wilt and loss, twig and branch dieback, bark lesions and timber staining and usually tree death. Not all infected ash will die as some trees maybe resistant, but the vast majority will – Pretty devastating really.
A recent article in the Telegraph – ‘Nobody wants the countryside to close down’ talked about the problems that the Duke of Devonshire has on his Chatsworth Estate.
His wonderful estate has 405 hectares of parkland and is packed with rare tree species. He thinks that between 10-20% of the estates tree population will need to be replaced as a result of pests and pathogens and its far from just Ash Dieback. However, despite his particular sadness at the loss of around one-third of the estate’s cedar trees, some of them at least 250 years old, he remains sanguine. He accepts that disease is just part of life for anyone who loves and reveres trees, and for him it’s all about adopting a policy of diverse species selection and then he believes, it can be bought under control.
It almost seems unbelievable that a fungus can kill such a beautiful mature tree, decades in age, but this is not the first time. Remember Dutch Elm disease some 45 years ago when the species disappeared from our landscape with the loss of over 25 million trees. There are presently other significant pest and diseases within the tree population, namely Ramorum in Larch trees which is leading to swathes of the species being cut down to try and curb the spread. There is also acute oak decline in oak trees and Dothistroma needle blight in pine trees.
Interestingly, whilst the forestry commission talks about the importance of biosecurity, even to the extent of cleaning vehicle tyres, chippers and chainsaws after working in infected areas, the Duke of Devonshire is quite clear that we are going to have to survive this nasty outbreak of tree disease without basic bio-security – after all, is it realistic to start demanding that all visitors to woodland disinfect their footwear or bike tyres?