A Guide to Soil Quality Monitoring for Long Term Ecosystem Sustainability on Northern Region National Forests

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Forest Habitat Types of Montana
PRODUCTIVITY/MANAGEMENT AND SOIL EXCERPTS

[Excerpted from: Pfister, Robert D., Bernard L. Kovalchik, Stephen F. Arno, and Richard C. Presby. 1977. Forest habitat types of Montana. Gen. Tech. Rep. INT-34. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest & Range Experiment Station. 174 p.]

PINUS CONTORTA SERIES

Soil—Soils throughout the Pinus contorta series are derived from a wide variety of noncalcareous parent materials (appendix D-1). Surface soils range from acidic to very acidic, and are generally gravelly with a broad range of textures from coarse loamy sands to silts. Ground surfaces have small amounts of rock or bare soil exposed, and moderate duff accumulations.

Productivity/Management—Timber productivity is low to moderate (appendix E). Based upon present evidence, Pinus contorta is the only tree species that can be managed successfully. Monoculture seems inevitable, but flexibility is available in silvicultural practices due to lack of competing conifers. Stands show evidence of light use (primarily spring to fall) by mule deer, elk, and occasionally moose. Water yield should be moderately high and subject to management by manipulation of vegetation. The gentle topography is well suited to many management activities; however, the esthetic appeal of these forests may be limited somewhat by their monotonous character.

Pinus contorta/Purshia tridentata h.t.
(PICO/PUTR; lodgepole pine/bitterbrush)

Soil—Soils in the PICO/PUTR h.t. were derived from obsidian-sand alluvial outwash. Surface soils are coarse sandy loams with acidic reactions. Ground surfaces had no bare soil or surface rock exposed; litter depth ranged from 2 to 5 cm. Cooper (1975) observed that the obsidian-sand outwash is often underlain by lake silts; he provides a more detailed description of soil characteristics for the same sampling area.

Productivity/Management—Timber productivity is low (appendix E-4) because of low site indexes and stockability limitations. Cone serotiny (closed cones) averaged 40 percent in our three sample stands. In an earlier study, Lotan (1967) found 38 percent serotiny in the same area, compared with 58 percent serotiny in an adjacent upland stand on a different habitat type. The open cone habit aids development of all-aged stands, while cone serotiny insures stand replacement following an intense wildfire.

Stermitz and others (1974) studied the relationship of soil characteristics to Pinus contorta regeneration in the West Yellowstone area (PICO/PUTR h.t.). They found a strong positive correlation between seedling survival and amount of fine material (silt plus clay) in the soil.

In addition to being hampered by coarse (droughty) soils, regeneration may be retarded by frost damage, since natural regeneration was observed to be more successful in shaded than in cleared areas.

Mule deer and moose appear to use the type heavily, at least during summer.

Pinus contorta/Vaccinium caespitosum h.t.
(PICO/OPHO; lodgepole pine/dwarf huckleberry)

Soil—Our stands were on a variety of noncalcareous parent materials (appendix D-1). Surface soils ranged from gravelly to nongravelly, from sandy loams to silts, and from very acidic to acidic. Ground surfaces had virtually no rock or mineral soil exposed; duff depths averaged 4.8 cm.

Productivity/Management—Timber productivity is moderate (appendix E-4). Pinus contorta is the only species that can be managed with assurance of success. Planting of other conifers should be conducted only on an experimental basis. Other management implications are similar to those for the ABLA/VACA h.t. or the PSME/VACA h.t.s east of the Continental Divide.

Pinus contorta/Linnaea borealis h.t.
(PICO/LIBO; lodgepole pine/twinflower)

Soil—Soils were derived from a variety of noncalcareous parent materials. Surface soils were acidic to very acidic sandy loams to silts. Gravel content averaged 21 percent. Ground surfaces had little surface rock and no bare soil exposed; duff depth averaged greater than 6 cm.

Productivity/Management—Timber productivity is moderate (appendix E). Pinus contorta is the only species that can be managed with assurance of success. Planting of other conifers should be conducted only on an experimental basis. Deer, elk, and moose evidently use these areas lightly from spring to fall.

Pinus contorta/Vaccinium scoparium h.t.
(PICO/VASC; lodgepole pine/grouse whortleberry)

Soil—Soils were derived from a broad variety of noncalcareous parent materials (appendix D-1). Surface soils were gravelly sandy loams to silts with very acidic to acidic reactions. Ground surfaces had an average of 5 percent rock but little bare soil exposed; duff depth averaged 4.7 cm.

Productivity/Management—Timber productivity is low to moderate (appendix E-4). Pinus contorta is the only species that can be managed with assurance of success. Planting of other conifers should be done only on an experimental basis. Mule deer, elk, and occasionally moose use the areas lightly during the summer. Other management implications should be comparable to those for the VASC and CARU phases of the ABLA/VASC h.t.

Pinus contorta/Calamagrostis rubescens h.t.
(PICO/CARU; lodgepole pine/pinegrass)

Soil—Soils were derived primarily from igneous parent materials (appendix D-1). Surface soils were acidic sandy loams to silts with average gravel content of 22 percent. Ground surfaces had little rock or bare soil exposed; duff depths averaged 2.6 cm.

Productivity/Management—Timber productivity is low to moderate (appendix E-4). Pinus contorta is the only species that can be managed with assurance of success. Planting of other conifers should be conducted only on an experimental basis. Other management implications should be similar to those for the PSME/CARU h.t., CARU phase, or the ABLA/CARU h.t.

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