Fungal degrade of wood

Plate 3 Sapstain on pine showing typical colonization pattern of ray tissues. 

Brown rot fungi. Brown rot decay of wood is typified by a dark, reddish brown appearance of the wood structure and a characteristic cubical checking. This appearance results from the degradation of carbohydrates 

Plate 4 Soft rot attack of Alstonia spp. showing typical cavity attack (Q, cell wall erosion (E) and cell wall penetration (P). Bar = 50 pm. 

Plate 5 Brown rot in pine showing typical cubical checking. Reproduced with permission, Mike Hale. 

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MA Goni, B Nelson, RA Blanchette, JI Hedges. Fungal degradation of wood hgnins Geochemical perspectives from CuO-derived phenolic dimers and monomers. Geochem Cosmochim Acta 51 39 5-4002, 1993. 

Bacterial attack is an early stage in the degradation of wood exposed in wet or moist conditions. Bacteria can be the dominant form of attack when fungal decay is suppressed by a wood-preserving treatment. Bacteria can attack the cell wall of wood by tunnelling, cavitation or erosion mechanisms (Eaton and Hale, 1993). 

We have used the terms decomposition and degradation to refer to the conversion of one or more of the structural polymers of wood to simpler molecules. Degradation can also be used to mean deterioration, i.e., to decrease the value of wood for some use we have used only deterioration in this narrower sense. Decay and rot refer to the fungal decomposition of wood. 

S Backa, A Brolin, and T Nilsson. Characterisation of Fungal Degraded Birch Wood by FTIR and Py-GC. Holrforschung 55 225-232, 2001. 

Experiments for fimgal degradation of pine flour were carried out by following an established procedure for fungal degradation of pulp (5). Pondarosa pine sapwood flour (30 mesh) was extracted with acetone/water (v/v, 9/1) and dried under vacuum. The moisture content was determined as 9.8 %. A mixture of wood flour (9.07 g oven-dried) and de-ionized water (10 mL) was autoclaved in 250 mL Erlenmeyer flask at 121 °C for 1 h. The autoclaved wood flour was inoculated with the P. cinnabarinus spore suspension (5 mL), and the moisture content of the wood flour adjusted to 80% with sterilized water. The culture was then incubated at 30 °C for pre-determined times. Twelve replicates were carried out for each cultivation time. 

Militz, H., Son, D.W., Gomez-Hemandez, L. and Sierra-Alvarez, R. (2003). Effect of fungal degradation on the chemical composition of acetylated beech wood. International Research Group on Wood Preservation, Doc. No. IRGAVP 03-40267. 

Ritschkoff, A.C., Ratio, M., Nurmi, A., Kokko, H., Rapp, A. and Militz, H. (1999). Effect of some resin treatments on fungal degradation reactions. International Research Gronp on Wood Preservation, Doc. No. IRG/WP 99-10318. 

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