The influence of causing primary blue-stain fungus Ceratocystis imperfecta on selected properties of Scots pine wood
The effects of development in wood the fungi causing blue-stain on the wood properties are not univocal. There were been undertaken investigation to clear the influence of such fungi on selected physical and mechanical properties of Scots pine wood.
Wet sap wood samples of fresh cut Scots pine wood (Pinus sylvestris L.) were infested with pure culture of Ceratocystis imperfecta Mill. et Grenz and exposed into its action through 1, 3 and 12 month. The properties of the infested wood and their twin control samples were determined after each incubation period.
The wood became the grey-black colour. The complete change of colour - ?E – measured by colorimetric Datacolor equipment was about 30 already after 1 month. The blue stain depth was from 1,0 mm - after 1 month to 5,0 mm (=whole cross - section) after 12 months. The absorptiveness of the stained wood greatly increased after 3 and 12 month of being infected by fungus. There was a tendency to drop the compression along the grains of blue stained wood in all investigated periods, but statistically essential changes appeared after only 12 months of the fungus action (mean drop 5%). The decrease of the impact of blue stained wood was statistically essential after 3 and 12 months of the fungus action (mean drop 13%). The statistically essential decrease in strength of wood was stated also by measuring of logarithmic decrement of torsional vibrations (mean drop 6%) and modulus of torsional rigidity (mean drop 2,5%). The stated changes in blue stained wood may to influence negative on usefulness of wood.