Bacterial decay tunneling bacteria

Bacteria and soft rot fungi are more tolerant of the low oxygen conditions in saturated wood, and in wood that is buried in sediments bacterial decay tends to predominate. Early reports identified unicellular bacteria in foundation piling and shipwreck timbers, but more recently three bacterial decay types in wood cell walls are now recognised - erosion, tunnelling and cavitation bacterial decay. 

Cell-Wall-Degrading Bacteria. The classification of bacterial decay types is based on the micromorphology of attack. Three main types of bacterial attack have been described so far through microscopy erosion, tunneling, and cavitation. They have been named after specific characteristics of the attack. Observations suggest that further forms of attack await description. Several other decay patterns of wood cells are suspected of being caused by bacteria, but no definite evidence is available. 

Environmental Factors. Very little is known about the influence of different environmental factors on bacterial decay. Boutelje and Goransson (101) reported that the degradation of foundation wood piles increased with increased nitrogen and phosphorus. Attack by tunneling bacteria in wood exposed in soil appears to be most frequently found in very fertile soils. 

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). 

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