  The white-rot fungus, Physisporinus vitreus, degrades the membranes of
bordered pits in tracheids and consequently increases the permeability of wood,
which is a process that can be used by the wood industry to improve the uptake
of wood preservatives and environmentally benign wood modification substances
to enhance the use and sustainability of native conifer wood species. To
understand and apply this process requires an understanding of how a complex
system (fungus-wood) interacts under defined conditions. We present a
three-dimensional fungal growth model (FGM) of the hyphal growth of P. vitreus
in the heartwood of Norway spruce. The model considers hyphae and nutrients as
discrete structures and links the microscopic interactions between fungus and
wood (e.g. degradation rate and degree of opening of pits) with macroscopic
system properties, such penetration depth of the fungus, biomass and
distribution of destroyed pits in early- and latewood. Simulations were
compared with experimental data. The growth of P. vitreus is characterized by a
stepwise capture of the substrate and the effect of this on wood according to
different model parameters is discussed.
