Grey Poplar (Populus × canescens) attacked by Honey Fungus (Amillaria mellea), dismantled and the stumps ground out. The Amillaria spp is an extremely aggressive fungus and will attack healthy tree roots, unlike all other fungi that require bark damage so the spores can enter into the xylem/wood. The mycelium moves through the soil from one host until it reaches fine roots of its next host. The first 2 photos are the ‘Boot Lace’ like mycelium that is under the bark of the affected tree and the last photo you can see the black spalting lines on the cross section wood, that is the mycelium.
Amillaria spp. has the largest biomass of any other living organism, bigger than a blue Whale.