6 Wood Discoloration

6.4 Protection 131
often A. areolatum and S. sanguinolentum compared to samples from healthy
forests (Schmidt et al. 1986).
Stereum sanguinolentum Bleeding Stereum
small, thin, resupinate to semipileate fruit body, soft-leathery-crusty, bowlshaped,
upper surface: felty, concentrically zonate, yellow-brown, whitish-wavy
margin (Fig. 6.4a); bright to grey-brown hymenium blood-red after injury;
dimitic (Breitenbach and Kränzlin 1986); amphithallic (Calderoni et al. 2003);
apart from the saprobic way of life also parasitic after penetration through
wounds and thus the most important species of “wound rot of spruce” (Butin
1995); stacked wood not attacked; genus Stereum with multiple clamps (Kreisel
1969).
Trichaptum abietinum Fir Polystictus
fruit body: annual, resupinate to semipileate and pileate, singly and roofing
tile-like; upper surface: white-grey-brown, thin, felty, hirsute, zonate, leathery;
pore surface: young net-shaped to porous, old: labyrinthine; young hymenium
reddish with angular violet pores, later brown-violet; dimitic (Breitenbach and
Kränzlin 1986); tetrapolar heterothallic (Nobles 1965); saprobic on stumps,
stored logs and finished wood; severe white rot at high wood moisture; rarely
on living trees (Kreisel 1961).
6.4
Protection
To avoid microbial wood discoloration, the generally suitable measures against
fungi (e.g., Liese et al. 1973; Liese and Peek 1987; Groß et al. 1991; Yang and
Beauregard 2001) are listed in Table 6.2.
Felling in the cold season and fast processing of the stems through well
coordination between forestry and wood industry reduces microbial activity
during storage of the stems in the forest. Cool, shady, and ventilated storage
without ground contact and with unhurt bark to maintain high wood moisture
content and to prevent lateral infections are favorable. Lumber discoloration
can be prevented by prompt air-drying in well-ventilated stacks protected
against rain by a roof, or by kiln-drying. Wet storage of stemwood by sprinkling
or ponding protects against fungi and insects. Currently, stem storage
Table 6.2. Preventive measures to avoid microbial wood discolorations and decay
– felling in the cold season
– appropriate storage of fresh wood
– coordination between forestry and wood industry
– drying
– wet storage
– storage in N2/CO2 atmosphere
– chemical preservation
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