Tree cull to halt disease

Haigh Hall rhododendrons
Haigh Hall rhododendrons

CONSERVATIONISTS are having to rip out every rhododendron bush in Haigh Country Park in a bid to thwart the spread of a virulent plant disease.

The drastic measures against the colourful plants have been reluctantly agreed on by Wigan Leisure and Culture Trust (WLCT), who manage the site on behalf of Wigan Council.

This was after experts identified ramorum disease - caused by a fungus-like pathogen called Phytophthora ramorum (P. ramorum) - on the site, which poses a significant risk to the 100-acre woodland.

The disease is responsible for destroying more than three million trees to date in the UK since it was first identified in 2002.

So far, WLCT has identified several infected areas of rhododendrons. Rhododendrons act as “sporulating hosts”, leading to a higher infection rate in the trees that surround the infected rhododendron bushes.

Removal of the rhododendrons from the site will protect the woodlands at Haigh Country Park and contribute to the national strategy to contain the spread of infection.

Graham Workman, Biodiversity Services Manager for WLCT, said: “Doing nothing is not an option. This work is compulsory and part of a national strategy to stop the spread of infection. By working now to remove the rhododendrons from site we can safeguard the future of this regionally significant woodland.”

The disease is called Sudden Oak Death in North America, where a slightly different form of P. ramorum has killed millions of North American native oak and tanoak trees. However, the name is misleading in the UK, where our two native species of oak have proved resistant to the disease, and the name “ramorum disease” is preferred. The disease can attack several other species of trees including beech, larch, ash, horse chestnut and sweet chestnut, and can take years to damage trees to the point where they need to be felled, although it kills larch trees very quickly.

WLCT is currently scientifically mapping out the number and locations of rhododendrons on site with partners from Red Rose Forest. This study will form the basis of a funding application to the Forestry Commission, who will fund 80 per cent of the removal costs. Early estimates suggest the work could cost £100,000.

Jake Thompson, Woodland Officer from the Forestry Commission, said: “The Forestry Commission support the work of WLCT in the woodland at Haigh Hall.

“Infected rhododendrons can host millions of P.ramorum spores, which can go on to infect and kill a wide range of tree species and woodland plants. We have already lost more than 3 million larch trees in the UK to this disease, and we have to do everything we can to control it if we are not to lose many millions more.”

Removal of the bushes will take place during the winter, when visitor numbers are lowest. All of the plant material will be burned on site to prevent spread of the disease.

The disease only affects plant life and is not harmful to humans. Work is scheduled to be completed by the winter of 2015.