Abstract:
Wood degrading ability and tolerance to wood-preserving chemicals
of several fungi isolated from Douglas-fir utility poles were
investigated by the agar-stick and soil-block methods. Birch (Betula.
sp. ) wood sticks and western hemlock (Tsuga heterophylla) wood blocks
were used.
The soil-block and agar-stick tests provided identical weight
loss rankings of the eight fungi from Douglas-fir poles. Breaking
radius appeared to be a more sensitive and rapid indicator of decay
than was weight loss and provided a reasonable basis for detecting
decay fungi. Decay caused by the brown-rot fungi, Poria carbonica
and Poria monticola was more severe with increase in incubation time
expressed either as strength reduction or weight reduction. The
white-rot fungus, Schizophyllum commune caused relatively little
weight loss and gave erractic results. Except for Phialophora
fastigiata., the fungi-imperfecti caused relatively little weight loss
but a relatively large change in breaking radius after twelve weeks.
In the preservative tolerance test, the brown-rot fungi were
highly resistant to ammoniacal copper arsenite and moderately tolerant
to creosote and pentachlorophenol. The white-rot fungus was
susceptible to all preservatives except creosote. The fungi-imperfecti,
Hyalodendron lignicola and Phialophora fastigiata were highly
tolerant to all preservatives.
In a study of classifying hymenomycetes isolated from Douglasfir
utility poles into brown-and white-rot fungi by the oxidase test
method, brown-rots were more prevalent than white-rot fungi. The
intensity of the oxidative reaction and the time required showed considerable
variation among the white-rot fungi.
