Insects wood decomposition

Wood is an anisotropic material that undergoes uneven dimensional changes and, under extreme variations of environmental conditions, becomes distorted and warped (see Chapter 10). Exposed to the atmosphere, wood is also susceptible to the mechanical forces of wind and rain, and the effects of solar radiation the latter, in particular, causes discoloration initially, and then photochemical degradation, which often results in the wood s total decomposition. Wood is also prone to consumption by bacteria, fungi, insects, and rodent animals (Unger et al. 2001). 

Table HI. Decomposition of Wood by Some Insects and Marine Borers...

The cardinal rules for proper use of wood can be stated simply keep wood dry, and, if you can t keep it dry, use naturally durable or preservative-treated wood. The first rule is based on a simple biological principle liquid water is needed in wood cells to provide a medium for diffusion of the enzymes or other metabolites by which wood-decomposing organisms digest the wood substance. If there is no liquid water present inside the wood cells, there will be no medium for diffusion, and therefore no biological decomposition except for certain insects of relatively minor importance. Thus, as long as wood is kept below its fiber-saturation point (about 27% of its dry weight), it will never decay. 

Uses and Potential Uses (26, 139). Although wood partly degraded by fungi or attacked by insects sometimes has increased aesthetic appeal for use in decorative paneling, wooden bowls, or other household items, a decrease in attractiveness and usefulness is more often the case. Thus biological decomposition usually leads to a decrease rather than an increase in the value of wood. 

Plasticizer, environmental decomposition of trichloroethylene Solvents, cleaners Wood preservatives, insect repellants, cosmetics Tar removers, waxes, degreasers Tar removers, waxes, degreasers Asphalt products, shampoos, skin treatments... 

OOD IS DECOMPOSED BY MANY DIFFERENT BIOLOGICAL AGENTS if adequate environmental conditions are available. Fungi, bacteria, and insects may all attack wood and use cell wall components or cause mechanical disintegration. Wood in natural environments is usually colonized quickly by microorganisms and insects, and the process of decomposition begins. Structural polymers in wood are gradually reduced to simpler molecules, and finally to CO 2 and water. 

The simplest alkane (that is, with n = 1) is methane CH4, which is a natural product of the anaerobic bacterial decomposition of vegetable matter under water. Because it was first collected in marshes, methane became known as marsh gas. A rather improbable but proven source of methane is termites. When these voracious insects consume wood, the microorganisms that inhabit their digestive system break down cellulose (the major component of wood) into methane, carbon dioxide, and other compounds. An estimated 170 million tons of methane are produced annually by termites It is also produced in some sewage treatment processes. Commercially,... 

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