berg (1963), Jane (1970), Panshin and DeZeeuw (1970) and 
Wardrop (1964). 
Wood Degradation 
Once severed from its association with a living system, wood 
is ordinarily decomposed beyond recognition within a matter 
of years. This decomposition is principally biological in nature, 
effected primarily by fungi, particularly the Basidiomycetes, 
which utilize the holocelluloses and lignins constituting vascu- 
lar tissue for their metabolic processes. 
Fossilization, with preservation of histological detail, appar- 
ent or real, is restricted to a limited number of geological 
situations with suitable biogeochemical histories. The en- 
vironmental parameters of such situations are essentially those 
which arrest or curtail microbial activity, particularly that of 
the lignin-digesting fungi. Among the more important of these 
parameters are (a) moisture, (b) temperature, (Cc) aeration, (d) 
pH, and (e) sedimentary setting. Time appears to be of conse- 
quence only in reference to the duration of operation of one or 
more of the aforementioned factors when functioning ad- 
versely in effect. 
Moist wood is considerably more susceptible to decay than 
dry wood. Microbial activity is arrested in wood with a 
moisture content of less than twenty per cent of the fiber 
saturation point, the point at which cell walls are fully saturated 
with bound water but no free water remains within cellular void 
space. Also, fungal growth will cease when cellular void space 
is completely filled with water and oxygen is excluded. 
Temperature intensifies the rapidity of decomposition. The 
optimum temperature range for active growth of most wood 
decay fungi is between 2) and 30 Celsius; below approximately 
4 and above about 40 Celsius, fungal activity virtually ceases 
(Kaarik, 1974). Hydrolytic breakdown of the polysaccharides 
and to a lesser extent, lignin, is promoted when temperatures 
reach the boiling point of water (Browning, 1963). 
Exclusion of oxygen is perhaps the most essential of condi- 
tions for the preservation of wood in nature. Most of the 
organisms responsible for decay of wood, including all of the 
lignin-digesting fungi, require oxygen for their respiration. 
Water-logged wood ‘‘mined”’ from stagnant lake bottoms after 
a hundred or more years of submergence was found to be 
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