ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

RAIN
The major precipitation instrumentation consisted of five permanently located
ti ppi ng bucket recordi ng rai n gauges and eight scattered Paci fi c rai n cans. Ti ppi ng
buckets were located at fully instrumented weather stations (fig. 1) in a lower
uncut-control and group-selection unit, and in an upper clearcut and shelterwood
unit. Their charts were checked daily and collected weekly.
Tipping bucket gauges provided the bulk of the precipitation data used in
this study. Daily, monthly, and annual summaries were prepared by si lvicul tural
treatment for comparative analysis. Rain can data served as a back-up to the
mechanical recording devices , provided supplementary preci pi tati on data for the
unmoni tored silvicul tural and control treatments, and aided in the evaluation of
individual storms. Pacific rain cans were set out seasonally in conjunction with
the permanent stations and at eight other semi-permanent locations surrounding the
study site. Each was checked weekly or after every major storm. A single snow gauge
was used year round to record both rain and snow in a clearcut adjacent to study
site.
SNOW
Twenty-six snow courses (fig. 1) were established within a1 1 si lvicul tural
treatments and control areas to measure snow accumulation and me1 t, redistribution,
elevational effects, and variability among and between silvicul tural treatments,
residue treatments, and control areas. Fol lowing logging snow course sample points
were randomly selected, permanently marked, and remeasured.
Samples were taken monthly during accumulation and weekly during me1 t with a
standard Federal snow sampler directly downhi 11 from each snow course sample point.
Both depth and water equivalent were recorded to the nearest 0.5 inch (1.3 cm).
Condition of soil and duff under the snowpack were noted. Supplementary snow samples
to evaluate residue treatments was performed about the first of April in 1977 and
1978 in the two clearcuts and shelterwoods by taking 30 samples within each residue
treatment.
Eight snowmel t lysimeters (Haupt 1969) were instal led to more precisely rnoni tor
silvicultural effects on snowmelt rates. Lysimeters were located within an upper and
lower control area and each of the six silvicul tural treatments at the same aspect
and elevation in order to minimize treatment and cl imatic influences. The lysimeters
were attended almost daily through the snow accumulation period and once or twice a
day during intense me1 t periods.
Snow-water equivalent (inches) from the snow courses and lysimeters was used to
calculate annual precipitation within the treatment areas and to estimate areal snow-
water equivalent for si lvi cul tural and residue treatments.
Soil Water
Before logging, 10 permanent points were systematically located at 100-foot
(30.5-m) intervals within each of the four residues treatments in each of the
clearcut and shelterwood cuttings and the control areas. Five points were located
within each of the eight group-selection cuts (small clearcuts) at various intervals
within the cutting, depending on the size of opening.