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ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

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surface of unburned and hard-burned m<strong>in</strong>eral soil than below a litter-covered surface<br />

or a charcoal -covered surface. Hermann (1 963) found the highest soi 1 moisture tension<br />

occurred <strong>in</strong> soil with a bare surface. Organic layers conserve soil moisture, but<br />

produce high surface temperatures.<br />

Table 6,--Precipitation received at the soil surface at Coram, by cutt<strong>in</strong>g method.<br />

1975<br />

June<br />

July<br />

August<br />

September<br />

Totals<br />

1976<br />

June<br />

July<br />

August<br />

September<br />

Totals<br />

1977<br />

June<br />

July<br />

August<br />

September<br />

Totals<br />

The shade of vegetation reduces evaporative losses and surface temperatires, but<br />

frequently not enough to compensate for the moisture used by the vegetation. Hall<strong>in</strong><br />

(1 968) found moisture tensions at 18 cm depths <strong>in</strong> revegetated cutovers to range from<br />

18-85 atm and from 3-13 atm where vegetation was removed. Some materials, such as<br />

BCD, appear to act as moisture s<strong>in</strong>ks (Harvey 1980). Newman (1980) and Packer (1980)<br />

provide more specific <strong>in</strong>formation about the soil moisture effects of various treat-<br />

ments.<br />

Evaluat<strong>in</strong>g w<strong>in</strong>d flow above and with<strong>in</strong> forest canopies is extremely complex.<br />

There is great variation, but the differences are important. We did not evaluate <strong>in</strong><br />

detail the effect of harvest<strong>in</strong>g and residues on w<strong>in</strong>d, but speed and direction at 10<br />

feet <strong>in</strong> height were measured at Coram for each cutt<strong>in</strong>g treatment. Our data supports<br />

the results <strong>in</strong> the 1 iterature that w<strong>in</strong>d speeds <strong>in</strong> the canopies of partial and uncut<br />

stands are less than those above clearcuts. W<strong>in</strong>d velocity and direction affect seed<br />

dispersal and natural regeneration (Shearer 1980). Much is known about the effects<br />

of open<strong>in</strong>g sizes and canopy height on w<strong>in</strong>d movement. Bergen (1976), Oliver (1971),<br />

and others discuss air flow with<strong>in</strong> the forest canopy. If the understory is sparse,<br />

w<strong>in</strong>d velocities at the height of canopies are lower than above or below cqnopies.

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