British trees are home to a number fungi, not all of which are harmful to the tree in question.Tree Fungi can be harmful (pathogenic), non-harming (Saprotrophic) and helpful (symbiotic).
The most common symbiotic relationship between trees and fungi is an infection of the soil around the roots known as Mycorrhizae. This mutually beneficial infection has the fungi eating the sugars produced by the tree during photosynthesis, in return the fungus enhances the trees ability to uptake water and soil nutrients like nitrates and minerals. This form of symbiosis seems to have first evolved about four-hundred million years ago during the Emsian period of the Devonian Age, which is around the time that trees really started to spread across the world.
Ectomycorrhizae: Mainly infesting oaks, birches, willows, pines, and the non-native dipterocarps and eucalypts these infections form between the roots of these trees and consist of the Basidiomycota, Ascomycota, and Zygomycota families of fungi. They are characterized as having fruiting bodies (mushrooms and toadstools) that appear above ground usually near the tree.
Arbuscular mycorrhizae: The most common form of plant symbiosis on the planet according to many researchers. Approximately seventy to eighty percent of all vascular plants are infected. These infections are characterized by the lack of fruiting bodies.
These fungi feed exclusively on dead organic matter, as such they don't generally damage a living tree, but the presence of these fungi on a tree can be an indicator of ill health, especially when found on a leafless area, or limb. Areas of damage to the tree resulting in dead wood tend to become infected with these fungi causing rot, leading to structural collapse.
Brown-Rot: Characterized by the dead wood breaking into red-brown coloured, crumbly, cubical chunks. Brown Rot is always a serious problem to the structure of a tree, and spreads rapidly.
White-Rot: Characterized by the dead wood paling to white and softening into a fibrous material. White-rot is usually less troublesome than Brown-rot but can still lead to structural collapse.
Soft-Rot Characterized by a slow weakening of the wood, usually involving long, thin open spaces forming within the wood, or splintering similar to Brown-rot.
Names:Daldinia concentrica, King Alfred's Cake, cramp balls, and coal fungus
Hosts: Broadleaves, usually Ash
Attacks:Dead branches in most cases
Consequences: May lead to branch breakage.
These fungi are similar to viral or bacterial infections. They are diseases and will weaken and kill the tree they infect. Many have symptoms very simlar to attacks of Saprotrophic Fungi, such as rotting, but they affect living wood rather than dead. There are a lot of fungal diseases that we encounter repeatedly, here are some examples.
Names:Armillaria species, oak fungus, honey mushroom, shoestring root rot
Hosts: Broadleaves and Conifers.
Attacks: Roots and base stem.
Consequences: Wood loses strength leading to root fracture and windthrow.
Names:Ganoderma adspersum, Artist's Fungus
Attacks: Stem base and roots
Consequences: Wood becomes soft, may lead to root fracture amd windthrow.
Names:Ganoderma applanatum, Artist's Bracket, Artist's Conk, Flacher Lackporling,
also classified as (Boletus applanatus, Fomes applanatus, Fomes vegetus, Ganoderme aplani, Ganoderma lipsiense,
Polyporus applanatus, and Polyporus vegetus)
Hosts: Broadleaves, especially beech and poplar.
Attacks: Dead heartwood and living sapwood.
Consequences: Softening of wood and may lead to windthrow or root fracture.
Names:Inonotus hispidus, Heart rot Ash, Shaggy Bracket
Hosts: Broadleaves, usually Ash.
Attacks: Stems and branches / limbs
Consequences: Wood becomes brittle, leading to fracture.
Names:Laetiporus sulphureus, Sulphur Shelf, Chicken-of-the-woods, Chicken mushroom, Chicken Fungus
Hosts: Broadleaves, commonly oak, yew, cherry wood, sweet chestnut, and willow
Attacks: Heartwood, mushrooms often seen on wounds.
Consequences: Wood becomes brittle and powdery leading to brittle fracture.
Names:Meripilus giganteus, Giant Polypore
Hosts: Broadleaves, usually Beech.
Consequences: Wood becomes soft, may lead to upper root fracture and windthrow.
Names:Ophiostoma novo-ulmi, Ophiostoma ulmi, Dutch Elm Disease
Hosts: Elm (carried by Elm beetle)
Attacks: Stems and Branches
Consequences: Vascular collapse leading to death of the tree. Dutch Elm disease looks like burning or tree de-hydration. This is due to the tree blocking it's own vascular system in an "allergic-reaction" immune response to the fungus.
Names:Phellinus tuberculosus, Bracket fungus
Hosts: Broadleaves, usually prunus species.
Attacks: Stems and branches.
Consequences: Wood becomes crumbly, leading to breakage.
Names:Piptoporus betulinus, Birch Bracket or razor strop
Attacks: Stems and Branches
Consequences: Brown rot, Wood becomes brittle, leading to brittle fracture.
Names:Polyporus squamosus, basidiomycete bracket fungus, Dryad's saddle, Pheasant's back mushroom.
Attacks: Stems and thick branches.
Consequences: Wood becomes brittle, or soft, cavity formation. Possible fracture.
Names: Ustulina deusta / Kretzschmaria deusta, Brittle Cinder, Carbon Cushion
Attacks: Heartwood, roots and stem base
Consequences: Wood becomes brittle leading to sudden fracture.
If you have any questions or concerns about a fungus on your property, please contact us via email, telephone, fax or post. Our expert arborists will be happy to examine the tree and assess risks from fungal growths to it and your property.