ENVIRONMENTAL CONSEQUENCES in rocky mountain coniferous ...

McFee and Stone 1966; Trappe 1965; McMinn 1963) shows this material is an
effective organic substrate in forest soils. This report describes the ability
of various types of organic matter to support abundant, active ectomycorrhizal
roots in soils from a broad range of forest ecosystems throughout the northern
Rocky Mountains.
MATERIALS AND METHODS
Soil sampling methods and analytical procedures have been described in the
authors' other pub1 ished reports (Harvey and others 1979; 1978; 1976). To sum-
marize, data on ectomycorrhizae are based on numbers of active associations (root
tips) contained in measured volumes of various soil horizons from soil cores taken
randomly throughout six experimental sites. Down woody residues were measured by
the planar intersect method (Broy 1974). Soil moisture contents were determined
gravimetrically by drying at 105 C for 24 hours. Acidity was determined electro-
metrically, using a 1 :2 mineral soil-water ratio or a 1 :5 organic matter-water
ratio.
Except where otherwise noted in the figure legends, the differences among
treatments and sites, etc., on which we have based our conclusions were significant
at least at the 0.05 probability level. Perhaps more important, these differences
were generally evident throughout a wide variety of ecosystems from both paired
samples and samples taken at different times and/or different places. Therefore,
we feel the patterns and trends shown here provide a true picture of most northern
Rocky Mountain soil s.
In general, the term northern Rocky Mountains applies to ecosystems that can
be described as "winter-moist" and "summer-dry" . Winter snow accumulations are
moderate, with very cold temperatures. Soil temperatures, except at the soil
surface, would be described as moderate to cold. Any substantial variation from
this pattern, even within the northern Rockies, will likely influence the relation-
ships described. Thus, great caution should be used in applying these results to
regions with deep snow accumulations, mild winter temperatures, or regions with
heavy summer rainfall. Also, these data are representative of,mature ecosystems.
Young or regenerating stands have not been investigated and may have di fferent
characteristics.
Precise locations and the geographical, climatic and other features of the
six experimental sites are described el sewhere in this symposium proceedings.
Approximate locations and some characteristics are as follows:
Priest River - Cedar-Hemlock Site (TSHE/PAMY)* - approximately 20 miles
northwest of the Priest River Experimental Forest in the northern Idaho
Panhandle; northeast aspect; previously undisturbed by man.
Coram - Hemlock Site (TSHEICLUN) - northwestern corner, Coram Experimental
Forest in northwestern Montana; northwest aspect; previously undisturbed
by man.
*Habitat type designations (Pfister and others 1977).