Urgent work is being carried out in The Dell in Lancaster's Williamson Park in a race to preserve woodland around the park.
The Dell has been blighted with diseased Rhododendron bushes and Lancaster City Council says the area will be inaccessible to the general public until they are removed. It is necessary to remove the diseased plants to prevent further infection.
The Rhododendron ponticum bushes are not native to Britain and are the bane of many working on environmental and wildlife projects around the country (there are even "Rhodie Bashing Days" to get rid of it). They're known to be very invasive and, once established, outcompete many native species. Due to their low habitat value they also drive many birds and wildlife species away.
Since their introduction to Williamson Park some areas have also developed a disease known as Phytophthora ramorum that threatens other areas of woodland in the park.
The disease is a fungus-like pathogen of plants that is causing extensive damage and mortality to trees and other plants in parts of the United Kingdom. It has also been found in a number of European countries, but mostly on plants and shrubs and has caused significant damage and mortality to many trees and other plants.
It was first identified in the mid-1990s as the cause of widespread devastation of wild oak trees in California and Oregon in the United States (which earned it the name 'Sudden oak death'), the pathogen was subsequently found in the nursery trade in North America in 2001. In Europe, including the UK, Phytophthora ramorum has been found mainly on container-grown Rhododendron, Viburnum and Camellia plants in nurseries. It was first detected in the UK in 2002 and measures to prevent its spread include the destruction of infected plants, a ban on imports of susceptible material from affected areas of the USA, and notification of movements of susceptible nursery stock.
The Forestry Commission says that infection of larch trees has now been confirmed at sites in Lancashire and Cumbria in North West England, the Peak District of Derbyshire in central England, and on the island of Mull in western Scotland. Other larch sites in Lancashire and Cumbria are also strongly suspected of being infected and are being further investigated.
Lancaster City Council are working closely with DEFRA to deal with infected species in Williamson Park and are taking preventative measures with the assistance of the Forestry Commission through Woodland Improvement Grants.
"It’s important to keep the park as healthy and as natural as possible," explains Elliott Grimshaw, Senior Outdoor Ranger for Lancaster City Council, "and the Rhododendron has spread so widely that it is decreasing the value of our woodlands.
“Williamson Park is renowned for its wide range of woodland flora and fauna, yet the Rhododendron are threatening the existence of these native species.
"It’s therefore important that we manage the park in a sustainable manner and increase the biodiversity within it to ensure it is available for others to enjoy in years to come.”
The current improvement works will commence in October and be completed by March 2012.
Fact sheets explaining to park visitors what is happening will be made available during this time.
• For further information about the removal of Rhododendron bushes in Williamson Park, please contact the park on 01524 33318 or visit www.lancaster.gov.uk/williamsonpark
• For more information about the Rhododendron ponticum bush and the problems it can cause please visit:
Forestry Commission website: www.forestry.gov.uk/pramorum