Honey Fungus (Armillaria mellea) is parasitic fungus responsible for the death of many trees and shrubs in the New Forest and for which there is no effective means of control.
However, it is a perfectly natural occurrence in relatively unmanaged areas of woodland here. Dead and dying trees all contribute to the biodiversity and unique character of the Forest. Fungi can enable trees to thrive – but they have the potential to eventually destroy them.
There are several species of Honey Fungus – some more pathogenic than others. They cause intensive white rot. This particular species can be very variable and the cap size can be 3-15 cm across, convex then flattened tawny to dark brown with brown scales at its centre. The white spores produced by the gills can often be seen covering the surrounding area with what appears to be a white powder, especially in the summer to early winter. It will grow in dense clusters around trunks or stumps, and in the New Forest its presence is probably most often noticed on fallen beech and birch trees.
This fungus also has the name Boot-lace fungus. This is because it spreads by long black cords called rhizomorphs which closely resemble bootlaces. These bootlaces are very strong and durable and enable the fungus to spread from one tree to another. ‘Bootlaces’ can easily be found underneath the bark of infected trees at any time of the year.
Honey Fungus can be the nightmare scourge of gardeners because it is so difficult to eradicate due to these rhizomorphs. They are even bioluminescent. When trenches were dug in the World War 11 revealing them, it was a concern that the position of the trenches might be made visible by glowing in the dark! Similarly in the London ‘blackout’, timber yards could glow at night, which might attract enemy bombers.