Urgent work to remove dead and diseased ash trees in a Brighton woodland is under way. …Before the felling started ash trees were inspected for signs of the ash dieback fungus, and large trees which appear to be fighting the disease have been left. Alan Robins, cabinet member responsible for parks says, where possible, tree trunks and stumps will be left to create habitats for wildlife. Thinning out the woodland could help to prevent the spread of ash dieback, the council says. Peter Small, arboriculture manager for the council, says there are so many dead trees the woodland has become dangerous. He says the work “does look severe” and “afterwards these areas will look different”. The Woodland Trust says the fungus, which originated in Asia, overwinters in leaf litter on the ground. … The fungus eventually blocks its water transport systems, causing it to die.