Fungal wood decay is a biological process by which the hyphae of the fugus excretes exo-enzymes which degrade cellulose and lignin in the trees cell wall (SCHWARZE et al. 2004). This is a natural process in a forests ecosystem which allows for carbon and nutrient cycling, the regeneration of juvenile trees to replace dead and senescent trees and creates habitat for boring insects and higher order fauna. However, from a human perspective these decay causing organisms cause issues in both timber production and those wishing to establish and maintain trees in theurban environment.
Fungal hyphae growing in the lumen of the plant cell structure. From A to D showing the proliferation of exo-enzymes and the eventual splitting of individual cell structures.
(Source: Springer; Fungal Strategies of Wood Decay in Trees)
Image showing the progressing degradation of the plant cell by the fungal hyphae, eventually breaking through multiple cell walls and devouring the whole structure.
(Source: Springer; Fungal Strategies of Wood Decay in Trees)
With a few exceptions (latent decay or wound parasites) wood-decaying fungi will often first colonise a tree through a pre-existingwound (where the heartwood of the tree has been exposed). The wound may have occurreddue to a wind induced limb failure or a human induced mechanical injury.
We will now look at the colonizing strategy of two different decay causing organisms; Ganoderma applanatum and Fomitopsis pinicola
Managing Tree Risk 101 