Trees on the Steyning Downland Scheme have been hit by ash dieback disease, wiping out at least one third of them in one area.
The nasty fungus attacks ash trees and leaves them vulnerable to sudden collapse, so safety is a big concern.
One large ash fell near the Newham Lane entrance, damaging the charity’s information board there.
Matthew Thomas, project manager, said: “Ash dieback disease has really taken a hold on the Lower Horseshoe. We estimate at least a third of the ash trees there are already infected. It’s caused by a nasty little fungus with an unpronounceable name.
“Infected trees quickly become vulnerable to sudden collapse and that’s the immediate concern along the informal paths and Rights of Way on the Steyning Downland Scheme.
“We’re working with local foresters to remove infected ash as safely and as quickly as we can. This will mean some fairly big changes to the local landscape, particularly in the Newham Lane area, where almost every tree seems to be affected.”
From now to the end of March, the charity is planning some significant clearance along the Upper Horseshoe path, which will involve temporary diversions of the bridleway.
Matthew added: “A large portion of the trees on the Horseshoe are ash and so at the moment it’s looking like big changes to the landscape may lie ahead. It’s worth remembering, though, that nothing stays still in nature.”
The Horseshoe Woods are around 50 years old. Before that, there was just open grassland and scrub.