English Oak with severe symptoms of Acute Oak Disease
In 2010/11 The Rufford Foundation provided a grant of £100,000 to Forest Research.
Oak trees in Britain are under threat from a disorder known as Acute Oak Decline (AOD). Severely affected trees have symptoms of profuse stem bleeding, D-shaped exit holes of the Agrilus buprestid beetle and diminished canopies. Tree death can result in 3-4 years from the onset of symptoms. To date, most affected trees have been found in the Midlands and eastern England.
Re-investigation of earlier reports suggests that this condition may have been present in Britain from the 1990s, but since 2005 the incidence of AOD appears to have increased significantly; now thousands of trees are affected. Research is in the early stages of understanding the causes but a combination of factors appears to be involved.
A generous Rufford Foundation grant is funding research in 2011, enabling scientists to unravel the causes of AOD. With this grant a range of affected sites will be visited to look in more detail at possible causal agents, as well as taking samples for laboratory analysis. Currently there are several candidate organisms that may be causing the symptoms seen on the declining trees. These include the oak buprestid Agrilus biguttatus and several species of bacteria previously unknown to science. Sophisticated techniques such as metagenomic analyses and polyphasic phylogeny are used to investigate the microbial assemblage associated with AOD, as well as determine the identity and nature of their activity. Supported by The Rufford Foundation, scientists at Forest Research hope to determine the causes of AOD and develop strategies to mitigate ill-health in native oak, thereby ensuring its future in a changing environment.
