ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

Natural inoculation of residues may occur in two ways: through spores and
through vegetative hyphal growth. Spore inoculation may occur on any surface;
inoculation by vegetative hyphae usually will occur only from soil or wood on the
undersides of residue, Initial decay in conifer residue occurs on the underside in
contact with soil and is usually of the white-rot type. Decay on the upper surface
or the sides is usually of the brown-rot type. Aho (19743 states that decay pro-
gresses faster in residues in contact with the soil .
MOISTURE CONTENT
Moisture avai labil ity is a primary control 1 ing factor in decay. Pechmann and
others (1967) reported that substrates with moisture contents below 30 percent or
above 120 percent were not colonized by most fungi, particularly decay fungi.
Etheridge (1958) noted that moisture content of heartwood is dependent on species
and site and generally is less than sapwood moisture contents, although there are
exceptions. Etheridge (1958) also noted that even minor changes in moisture content
had significant effects on decay rates. Wood in contact with the soil readily
absorbs moisture from it. Other factors also contribute to increased residue
moisture cbntent and increased decay: shading, north-facing slopes, el evation,
compaction/stratification of wood residues, amount of soil organic matter, and
temperature.
As decay progresses, pore volume of the woody substrate increases, facilitating
the total amount of moisture that potentially could be present (fig. 4). Figure 5
reflects the effect of pore volume in terms of moisture holding capacity on the
Coram site between the control and clearcut-intensive utilization treatment. The
data indicate the soil-wood moisture contents are not affected by treatment and, as
a result, woody residues in this form would alleviate moisture stress in clearcut
areas.
200
Moisture
Content
(%)
100
300 Moisture Content
ClTotal Carbohydrate
Total
Carbohydrate
' Content
(% odw)
FCgure 4.-- Relationship between moisture content and d~cay progression
in brom-rotfed mugZas-fir. Decay associated uith Fornitopsis pin-i-coZa.
(Corn Experimental Forest, September 2977. All moisture content
values significantZy dffferent from each other: sF 0.01).
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