Coram Experimental Forest lies within the Flathead National Forest in the Northern Rocky Mountains of Montana. Spanning 7,500 acres (3,020 hectares), Coram Experimental Forest was established in 1933 for researchers to study western larch regeneration and management. Today, the research conducted and the extensive datasets collected at Coram continue to be critical for western larch management. Check out the Coram Experimental Forest Brochure for more information.
Coram was established in 1933 on the Flathead National Forest in northwest Montana as an area representative of the western larch (Larix occidentalis Nutt.) forest cover type distributed within the upper Columbia River basin. Western larch is a tree species that regenerates well in the exposed soil and sunny conditions that are typical after a fire or similar disturbance. Diverse and productive, the importance of this forest type to management priorities of federal land managers cannot be overstated. In the autumn, the foliage turns golden before falling, providing an opportunity for recreational viewing.
The Coram Experimental Forest represents western larch-mixed conifer forests of the Northern Rockies. Western larch research was centered at Coram Experimental Forest (CEF) to provide a scientific basis to regenerate and grow this important and valuable species. For example, the long-term silvicultural studies installed at CEF are allowing researchers and managers to understand the effects of multiple entries into stands on soil and forest productivity, as well as the potential of various silvicultural approaches to designing restoration of wildlife habitat. Climate and hydrological stations record variability in longterm weather and runoff.
The Coram Research Natural Area contains old, large forest used as a reference site for comparison to managed areas. Coram Experimental Forest also offers educational opportunities in the award-winning Walk With Larch Trail, which demonstrates the long-term effects of numerous silvicultural choices. At the headquarters on the Hungry Horse District Ranger Station, the International Larix Arboretum contains specimens of many larch trees of the world.
Wade, R. K. 2018. Models for plant self-thinning. Ecosphere 9(5):e02219. 10.1002/ecs2.2219
Schaedel, M.S., Larson, A.J., Weisbrod, C.J. and Keane, R.E. 2017 Density-dependent woody detritus accumulation in an even-aged, single-species forest. Canadian Journal of Forest Research, 47 (9), 1215-1221.
Jang, W., Keyes, C.R. and Graham, J.M. 2016 Evaluation of predictive models for Douglas-fir bark thickness at breast height following 12 biomass harvest treatments. Biomass and Bioenergy, 84, 118-123.
Wonn, Hagan T.; Hara, Kevin L. 2001. Height:diameter ratios and stability relationships for four northern Rocky Mountain tree species. Western Journal of Applied Forestry. 16(2): 87-94.
McClelland, B. Riley; McClelland, Patricia T. 2000. Red-naped sapsucker nest trees in northern Rocky Mountain old-growth forest. The Wilson Bulletin. 112(1): 44-50.
McClelland, B. Riley; McClelland, Patricia T. 1999. Pileated woodpecker nest and roost trees in Montana: links with old-growth and forest "health". Wildlife Society Bulletin. 27(3): 846-857.
Schmidt, Wyman C.; Shearer, Raymond C. 1999. Larix occidentalis Nutt.: western larch. In: Burns, Russell M.; Honkala, Barbara H., eds. Silvics of North America. Agricultural Handbook 654 Volume 1. Washington, DC: U.S. Department of Agriculture, Forest Service. p. 160-172.
Schmidt, Wyman C. 1998. Stand density in relation to biological functions in young western larch forests. In: Bamsey, Colin R., ed. Stand Density Management: Planning and Implementation: Proceedings of a Conference; 1997, November 6-7, Edmonton, Alberta, Canada. Edmonton, Alberta: Clear Lake Ltd. p. 101-111.
Tobalske, Bret W. 1992. Evaluating habitat suitability using relative abundance and fledging success of red-naped sapsuckers. The Condor. 94(2): 550–553.
Bidlake, William R.; Black, R. Alan. 1989. Vertical distribution of leaf area in Larix occidentalis: a comparison of two estimation methods. Canadian Journal of Forest Research. 19(9): 1131-1136.
Habeck, James R. 1988. Old growth forests in the Northern Rocky Mountains. Natural Areas Journal. 8(3): 202-211.
Sax, J. L.; Keiter, R. B. 1987. Glacier National Park and its neighbors: A study of federal interagency relations. Ecology Law Quarterly. 14: 207-263.
Stark, N. 1983. The nutrient content of Rocky Mountain vegetation: A handbook for estimating nutrients lost through harvest and burning. University of Montana, Montana Forest and Conservation Experiment Station, Missoula, MT. 81 p.
Turner, Monica Goigel; Gregg, William P., Jr. 1983. The status of scientific activities in United States Biosphere Reserves. Environmental Conservation. 10(3): 231-237.
Lauff, George; Reichle, David. 1979. Experimental Ecological Reserves. Bulletin of the Ecological Society of America. 60(1): 4-11.
McClelland, B. Riley. 1979. The pileated woodpecker in forests of the northern Rocky Mountains. In: Dickson, James G.; Conner, Richard N.; Fleet, Robert R. ; Kroll, James C. ; Jackson, Jerome A., eds. The Role of Insectivorous Birds in Forest Ecosystems; 1978, July 13-14, Nacogdoches, TX. New York: Academic Press. p. 283-299.
McClelland, B. Riley; Frissell, Sidney S. 1975. Identifying forest snags useful for hole-nesting birds. Journal of Forestry. 73(7): 414-417.
Klages, Murray G. 1974. Clay minerals of Montana soils. Proceedings of the Montana Academy of Sciences. 34: 12-18.
Behan, Mark J. 1968. Fertilization in western larch forests. Note 6. University of Montana, Montana Forestry and Conservation Experiment Station, Missoula, MT. 14 p. + figures and supplement.
Climate at Coram Experimental Forest is classified as a modified Pacific maritime-type. Occasional winter, continental-type polar air moves westward over the Continental Divide, and temperatures drop substantially for a few days. Seasons at Coram are classed broadly as: winter—November to March; spring—April to June; summer—July to August; fall—September to October.
Annual precipitation ranges from an average of about 35 inches (890 mm) at the lowest elevation of 3,300 ft (1,006 m), to 50 inches (1,270 mm) at the highest elevation of 6,370 ft (1,942 m). Precipitation falls mostly as snow. May through August mean temperature is about 61 °F (16 °C ) with highs occasionally exceeding 100 °F (38 °C). Winter temperatures average about 20 °F (-7 °C ), but rarely drop below -20 °F (-29 °C ). Growing season length (the number of frost-free days) ranges from 81-days near Abbot Creek, to about 160-days on a nearby east-facing slope. Current and historic precipitation data is available for the nearby Emery Creek SNOTEL site.
A rock layer primarily made of argillite and quartzite underlies most of the upper slopes. The lower areas have deposits of glacial outwash and till. A thin layer of volcanic ash covers about half of the forest. Rich loamy soils predominate. Soil depths range from a few centimeters on steep, upper slopes to over 9 ft (3 m) on gentle, lower terrain. Six soils exist at Coram Experimental Forest:
Coram Experimental Forest has a diverse mix of plants. Western larch (Larix occidentalis) grows almost everywhere at Coram with Douglas-fir (Pseudotsuga menziesii), subalpine fir (Abies lasiocarpa) and Engelmann spruce (Picea engelmannii). Hybrids of P. engelmannii and P. glauca (white spruce) grow at lower elevations.
Less common plants are lodgepole pine (Pinus contorta), western white pine (Pinus monticola), western hemlock (Tsuga heterophylla), and western redcedar (Thuja plicata). Western larch (L. occidentalis) and ponderosa pine (Pinus ponderosa) grow together on dry, lower-elevation ridges that have shallow soil, the only sites where ponderosa pine grows. At high elevations, larch grows with whitebark pine (Pinus albicaulis), a species nearly eliminated from Coram by white pine blister rust (Cronatrium ribicola). Occasionally, individual grand fir trees (Abies grandis) grow on warm, moist sites. Pacific Yew (Taxus brevifolia) and common juniper (Juniperus communis) grow in shrub form.
The only conifers growing within the range of western larch that are not represented on the experimental forest are alpine larch (Larix lyallii ) and mountain hemlock (Tsuga mertensiana). Predominant hardwood trees growing on Coram Experimental Forest are paper birth (Betula papyrifera), black cottonwood (Populus trichocarpa), and quaking aspen (P. tremuloides).
Coram has a diverse mix of shrubs including:
Common forbs are:
Several non-native plant species grow in Coram Experimental Forest. Most grow in disturbed areas, particularly along roads throughout the forest. Species listed as noxious in Montana include:
A comprehensive species list for Coram Experimental Forest is in the appendix of Shearer and Kempf, 1999.
Research began on the Coram Experimental Forest (CEF) in 1948 and the focus of the work has varied with time.
Resampling Forest Residues Utilization Study at the Coram Experimental Forest: Monitoring Forest Recovery and C & N Pools 30 Years Later. This study takes advantage of a long-term study installed at the CEF in 1974 to address contemporary and critical management information needs about the sustainability of harvesting forests for biomass utilization. The original treatment included three regeneration harvest types (clearcut, group selections, and shelterwood), three biomass removal levels (high, medium, and low) combined with prescribed post-harvest burning treatments (burned and unburned). Plots were re-measured in 2012. Several recent papers (2015-2018) provided the following: 1) Results indicated site productivity in this forest type was unaffected by these biomass removal levels. 2) The shrub community was very resilient to biomass harvesting in this forest type. 3) In this forest type, intensive biomass utilization (with or without broadcast burning) had few long-term impacts on soil properties. 4) Overstory retention (shelterwood with reserves and group selection) resulted in long-term regeneration growth reduction compared to clearcutting. Postharvest burning increased regeneration stem density and decreased mean regenerated tree size. When overstory trees were aggregated and cuttings were in groups, negative impacts on regeneration were relatively lessened. 5) Growth efficiency of Douglas-fir trees (the ratio of 5-year-basal area increment to total leaf area) was not affected by any treatment. These results confirm no apparent effect of biomass removal on site productivity for this range of biomass removal levels.
Influence of regulated stand densities in young western larch stands on individual tree and stand growth, 1961-present: Long-term analysis. In 1961 a study was installed in 10-year old second-growth larch stands to determine the trade-offs between individual tree growth and stand yield that were pre-commercially thinned at varying densities as well as varying number of entries; the study was remeasured every five years until 2000 and then again in 2015. Three recent papers (2017) provided the following results. 1) Thinning before stand age 10 years led to long-term constant yield across the tested densities, and constant volume across stand densities. The primary effect of early pre-commercial thinning was to control whether wood volume and growth are concentrated on few large, stable trees or many small, unstable trees. 2) Woody detritus sizes were similarly distributed but detritus biomass increased as stand density increased due to self-thinning. 3) Pre-commercial thinning did not affect total above-ground carbon storage but the particular treatment did affect the distribution of carbon among four pools of pre- and post-stand initiation wood. They found that 1) aboveground carbon was similar across treatments, 2) legacy deadwood still played an important role in C storage, and 3) given sufficient time since thinning, there is no trade-off between managing stands to promote individual tree growth and understory vegetation development and maximizing stand level C over the long term.
Pre-commercial thinning effects on snowshoe hare (Lepus americanus) habitat. Evaluate snowshoe hare usage of plots on pre-commercially thinned larch-mixed-conifer stands to determine which treatments might be applicable for snowshoe hare/Canada lynx habitat restoration. STATUS – All data have been collected and the analysis completed; a manuscript is being drafted with a completion date of August 2018. There was a significantly greater relative occurrence of snowshoe hare in non-precommercially thinned (non-PCT) than precommercially thinned (PCT) stands of the same age and similar geophysical characteristics. No significant difference was found in horizontal cover between treated and untreated stands. Stem density of the live and dead saplings and the overstory trees were greater in the non-PCT stands, as would be expected from the standard management prescriptions. In future analysis we will examine the interactive effects of vegetation structure and composition of each treatment with snowshoe hare relative abundance.
In 1938, 339 ha (838 ac) in the southeastern corner of Coram Experimental Forest were reserved as a natural area to preserve examples of late-successional western larch and interior Douglas-fir stands. Approximately 80 percent of the natural area is forested with 200+ year-old stands of mixed western larch and Douglas-fir. It was officially recognized as the Coram Research Natural Area (CRNA) in 1988.
In 1985, four long-term baseline monitoring plots were established in the 339 ha Coram Research Natural Area (CRNA); four more plots were added in 1993. Stand dynamics and photopoints are regularly recorded at each plot. This study is complemented by the studies on vegetation change and seedfall on permanent plots (1993, 1997). The plots were re-measured in 2000 and 2014. STATUS: All data are being prepared for submission to the Research Data Archives (CY2019).
International Larix Arboretum. In 1992, an International Larix Arboretum was established featuring larches of the world near Coram Experimental Forest on the grounds of the Hungry Horse Ranger District (Flathead National Forest) in northwestern Montana. This unique collection provides information to the public about the importance and differences among species, varieties, and hybrids in the genus Larix (commonly known as ‘larch’). Larches are distributed in the northern hemisphere and are a prominent component of the boreal, montane, and subalpine forests of North America, Asia, and Europe. Three of the ten species are endemic to North America; the other seven occur in Asia and Europe. STATUS: A draft education pamphlet about the larches in the Arboretum has been developed and tested and is being revised before publication and local distribution to classes of local middle-schoolers and the public.
Several ongoing collaborative studies have direct relevance to land management:
Scientists have maintained two weather stations, Desert Ridge (elevation 6,000 ft, 1,830 m) and Terrace Hills (elevation 3,500 ft, 1,070 m), at the Coram Experimental Forest since 1986. Available weather data includes precipitation, air temperature, relative humidity, soil temperature, wind speed, wind direction, and solar radiation. For access to these data, please contact the Coram Experimental Forest Manager.
Hydrologic flow measurements on the Abbot Creek and the Lunch Fork of Abbot Creek began in 1974. Both Abbot Creek and the Lunch Fork of Abbot Creek currently contain a one-foot Parshall flume. Flow data, beginning in 2004 for these two sites, are available in the Forest Service Research Data Archive.
The Emery Creek SNOTEL site, a meteorological station maintained by the Natural Resources Conservation Service near Coram Experimental Forest monitors accumulated precipitation, snow depth, snow water equivalent, and temperature.
In 1985, researchers established four long-term baseline monitoring plots within the CRNA; four additional plots were established in 1993. Researchers measured all plots in 2014. They recorded stand dynamics and photopoints at each plot. For a summary of results, see Elzinga and Shearer, 1997.
Re-measuring long-term studies is providing insights for new management questions, and Forest Service staff are planning new studies. CEF and its cache of long-term experimental silviculture studies can provide valuable guidance for restoration management.
Coram Experimental Forest headquarters are located on the grounds of the Hungry Horse Ranger District, roughly 3 miles (5 km) west of the experimental forest. They include two houses built around 1948 by the Federal Bureau of Reclamation during the construction of the Hungry Horse Dam. The houses function as offices and sleeping quarters for Rocky Mountain Research Station staff and cooperators. Please contact David Wright with questions concerning housing.
Coram Experimental Forest has approximately 33 miles (54 km) of roads. Two roads—FS 497 (the Desert Ridge Road) and FS 38 (the South Fork Road—are open to the public. Except for limited administrative access, all other roads in Coram are closed to motor vehicle use due to grizzly bear habitat restrictions.
Located only 7 km (11 mi) west of Glacier National Park, there are many reasons to visit the Coram Experimental Forest:
Q: I want to do research at Coram. Whom do I contact?
Q: How can I reserve the houses at Coram headquarters?
A: The houses are reserved for administrative use by research staff and cooperators and not available to the public. Researchers should contact the Manager to schedule use of the houses.
Q: Can I camp at Coram?
A: No, camping is not permitted.
Q: Can I cut firewood from Coram?
A: No, firewood cutting is not permitted.
We welcome ideas for new research and remeasurement of existing studies on the Coram. If interested, please contact the Scientist in Charge.