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A Guide to Soil Quality Monitoring for Long Term Ecosystem Sustainability on Northern Region National Forests
SOLO HOME > HABITAT TYPES > PLANT COMMUNITY CLASSIFICATION FOR ALPINE VEGETATION ON THE BEAVERHEAD NATIONAL FOREST, MONTANA > SLOPE COMMUNITIES
Plant Community Classification for Alpine Vegetation on the Beaverhead National Forest, Montana
PRODUCTIVITY/MANAGEMENT AND SOIL EXCERPTS
[Excerpted from: Cooper, Stephen V.; Lesica, Peter; Page-Dumroese, Deborah. Rev. 1997. Plant Community Classification for Alpine Vegetation on the Beaverhead National Forest, Montana. Gen. Tech. Rep. INT-362. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 61 p.]
SLOPE COMMUNITIES
Dry Slopes
Soils—Parent materials included limestone, calcareous sandstone, quartzite, granite, basalt, and gneiss. The only litter and duff present were immediately under vegetation canopies. Coarse fragment content ranged from 31 to 79 percent, averaging 55 percent. Texture of the fine fraction ranged from sandy clay to loamy sand, and modal texture was sandy clay-loam. Relative lack of substrate weathering was reflected in high soil reactions for both calcareous and noncalcareous sites, 7.7 and 6.6 pH. Mean organic matter content was only 8 percent, mean total nitrogen was 0.27 percent, and C:N ratio was 20:1.
Productivity/Management—Total production ranged from 207 to 964 lbs per acre, averaging 657 lbs per acre, with forb production (494 lbs per acre) far outstripping that of graminoids (163 lbs per acre). It is instructive to note that grass and forb coverage values of dry slopes approximate those of cushion plant communities, but dry slope production is twice as great. Greater dry slope production is due to a predominance of upright growth forms as opposed to cushion plants.
Moist Slopes
Soils—Parent materials included gneiss, quartzite, sandstone, calcareous sandstone, and limestone. Trace amounts of litter and duff were found only under individual plants. Coarse fragment content ranged widely, from 5 to 71 percent, and averaged 31 percent. The two stands with the lowest coarse fragment content (5 and 6 percent) were probably snowbed areas and had extensive pocket gopher (Thomomys talpoides) workings and soil erosion. Texture of the fine fraction ranged from clay to sandy loam; the modal textural class was sandy clay-loam. Soil reaction for both calcareous (7.3 pH) and noncalcareous (6.5 pH) substrates tended to be lower than for DRY SLOPES. Mean organic matter content was only 9 percent, mean total nitrogen was 0.18 percent, and C:N ratio was 17:1. Levels of organic matter and nitrogen were lower than for most other community types sampled.
Productivity/Management—Total production ranged from 391 to 1,104 lbs per acre; average production total was 646 lbs per acre; and component fractions averaged 479 lbs per acre for forbs, 167 lbs per acre for graminoids, and were very similar to DRY SLOPES values.