Tree felling works underway on the A345. Copyright Landmarc Support Services. The Defence Infrastructure Organisation ( DIO), together with its industry partner, Landmarc Support Services (Landmarc) and subcontractor KWR Plant Hire, carried out the tree-felling clearance scheme to remove trees infected with ash dieback. Thousands of ash trees across Salisbury Plain Training Area, as well as many more across the country, are infected with the disease. There is no cure or treatment and over time infected trees will weaken, causing branches to fall and trees to eventually die and collapse. This presents a significant health and safety risk, especially alongside roads, public rights of way and woodland areas used by military personnel for training and the public for recreation activities.