The effect of primary blue-staining fungi on the strength properties of Scots pine sapwood
The fungi action may have influence on wood properties especially Basidiomycotina fungi causing wood decay. The investigation of influence of fungi causing mainly wood discoloration and disfigurement on wood properties is still in development process. There were determined the differences between the bending strength, the compression along the grains and impact strength of control and blue stained sets of Scots pine (Pinus sylvestris L.) twin sapwood samples. The one part of each twin sapwood samples sets was exposed for 1, 3 or 12 months to the action of pure culture of blue staining fungi Ceratocystis penicillata, Cladosporium herbarum, Discula pinicola or their mixture while the second part of sets was control samples. Research showed that the changes in wood strength properties were dependent on the fungi action period and to get worse with the fungi action prolongation. The statistically significance of decreasing of sapwood properties was greater by impact strength and compression along the grains strength than by bending strength investigation. The level of decreasing the wood properties caused by blue-stain fungi during 12th months of their action was larger for impact strength (over –13%), smaller for compression along the grains strength (about –5-8%) and only very little (to –3%) and with less statistically significance for bending strength. The impact strength and compression along the grains strength appeared to be more sensitive indicators of the blue stain fungi action than bending strength.