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Tenderfoot Creek Experimental Forest

Scientist in Charge: 

General Description

Established in 1961, Tenderfoot Creek Experimental Forest (TCEF) encompasses the headwaters of Tenderfoot Creek in the Lewis and Clark National Forest. Tenderfoot Creek Experimental Forest is the site of diverse research on the productivity and biodiversity of east-side lodgepole pine communities, forest monitoring and health, hydrologic processes, and much more.

Background Information and History

Lodgepole pine stand.
Lodgepole pine stand.
Tenderfoot Creek Experimental Forest lies roughly 40 miles (64 km) north of White Sulphur Springs, Montana, and 71 miles (114 km) southeast of Great Falls, Montana. Established in 1961, its 9,125 acres encompass the headwaters of Tenderfoot Creek in the Little Belt Mountains on the Lewis and Clark National Forest. Tenderfoot Creek is a major tributary of the Smith and Missouri Rivers, and provides an important hydrologic resource for much of central Montana. Lodgepole pine and mixed lodgepole pine with Engelmann spruce and subalpine fir stands grow on approximately 8,681 acres. Wet meadows cover 311 acres, and drier grass and scree slopes make up another 133 acres. Elevations range from 6,035 to 7,941 feet.

The U.S. Forest Service originally established Tenderfoot Creek in 1961 to investigate lodgepole pine harvesting techniques that maintained soil stability while increasing water yield. Apart from baseline data, such as timber inventory, soil information, fuel analysis, and ecological habitat type descriptions, little research occurred until the late 1980s. The Forest Service expanded the scope of Tenderfoot Creek research in the late 1980s to include fire history, fisheries, plant composition, animal communities, and other physical and biological factors as they relate to landscape-level management (see TCEF bibliography).

Representative of the vast expanses of lodgepole pine (Pinus contorta var. latifolia) that grow east of the Continental Divide in Montana, Tenderfoot Creek’s fire-prone forests are typical of those growing at moderate-to-high altitudes in the Northern Rocky Mountains. Forest stands are classified as 1-aged (47% of the forested area) and 2-aged (53% of the forested area); these were created by fires in the past that were mixed in severity or stand-replacing that burned all trees (see Fire History of Tenderfoot Creek Experimental Forest). Engelmann spruce (Picea engelmannii) grows in the area's sparse but species-rich wetlands; subalpine fir (Abies lasiocarpa) grows in older stands throughout the forest, and whitebark pine (Pinus albicaulis) grows in the higher ridgetops. Several naturally occurring open meadows, rich in woody plants, exist throughout the experimental forest.

Onion Park Research Natural Area

Onion Park Research Natural Area (RNA) lies on the easternmost extension of the Tenderfoot Creek Experimental Forest. Researchers use this minimally disturbed 1,209-acre sub-watershed to monitor natural ecological change such as plant succession and stream dynamics. Baseline information (see Botanical and Ecological Resources Inventory, Mapping and Analysis) collected within the RNA helps researchers assess the effectiveness of management activities performed on similar sites.

Onion Park RNA contains several important features:

  • A 73-acre subalpine moderately moist meadow with high forb diversity, named for the presence of three species of onion (Allium spp.). Onion Park also contains pink agoseris (Agoseris lackschewitzii), a sensitive species for the Northern Region.
  • Headwaters of Tenderfoot Creek, a major tributary of the Smith and Missouri rivers.
  • Subalpine forests where lodgepole pine (Pinus contorta) dominate in the overstory, and classified as the subalpine fir/grouse whortleberry and subalpine fir/bluejoint reedgrass habitat type.
  • Quartzite Ridge, a talus/scree slope with scattered lodgepole pine and whitebark pine (Pinus albicaulis).

Ecological Information


Tenderfoot Creek Experimental Forest has a generally continental climate with occasional influence of the Pacific maritime climate along the Continental Divide from Marias Pass south. Annual precipitation averages 35 inches (880 mm), and ranges from 23 to 41 inches (594 to 1,050 mm) from the lowest to highest elevations. Monthly precipitation generally peaks in December or January at 4 to 5 inches (100 to 125 mm) per month, and declines to 2 to 2.3 inches (50 to 60 mm) per month from late July through October. About 70 percent of the annual precipitation falls during winter, usually as snow. Intense summer thunderstorms are relatively rare, and most overland flows that cause soil erosion come from snowmelt.

Mountain soils generally are at field capacity at the beginning of the growing season in early spring. At lower elevations and on dry south-facing slopes, limited soil moisture stops plant growth for shallow rooted plants by mid-July. At higher elevations, growing seasons are shorter and killing frosts rather than moisture stress limit growth. Freezing temperatures and snow can occur every month of the year at the Tenderfoot Creek Experimental Forest and throughout the Little Belt mountain range. For hardy native plants, growing seasons average 45 to 75 days, decreasing to 30 to 45 days on the higher ridges.

Current and historic temperature and precipitation data is available online for the Onion Park and Stringer Creek National Resource Conservation Service snow telemetry (SNOTEL) sites. Annual precipitation data is available at the Forest Service Research Data Archive.


The most extensive soil groups are the loamy skeletal, mixed Typic Cryochrepts and clay-like, mixed Aquic Cryoboralfs. Rock talus slopes are prominent on the perimeter of the landscape, but rock outcrops are confined chiefly to areas adjacent to main stream channels. Soils in the grassland parks range from well to poorly drained. Seeps and springs are common over the entire forest.

The geology of the Tenderfoot Creek Experimental Forest Forest is characterized by igneous intrusive sills of quartz porphyry, Wolsey shales, Flathead quartzite, and granite gneiss. The northern part of the forest occupies the highest elevations and steepest upland topography and is underlain by igneous intrusive granitic rocks. The arched bedrock in the area was formed from metasediments of Cambrian Age consisting mainly of argillites and quartzites. Past glaciers cut through the land, creating broad basins where streams are beginning to regain a branching, braided pattern. For a complete geological assessment of the Tenderfoot Creek Experimental Forest see Geology of the Tenderfoot Creek Experimental Forest Little Belt Mountains.


Tenderfoot Creek contains four forest habitat types: subalpine fir/grouse whortleberry; subalpine fir, blue huckleberry; subalpine fir, bluejoint; and subalpine fir whitebark pine/grouse whortleberry (see Habitat Types of the Tenderfoot Experimental Forest). Besides these four ecosystem types, lodgepole pine/huckleberry community type dominates a portion of Tenderfoot Creek. In this case, however, the community type occurs because of the subalpine fir/grouse whortleberry habitat type that has extensive and continuous regenerating fir and old growth. Within each habitat type, stands of different age classes occur intermittently. Four other general land descriptions include talus slopes, rock outcrops, grassland parks, and wet meadows. For a complete vascular flora of the Tenderfoot Creek Experimental Forest see Vascular Flora of the Tenderfoot Creek Experimental Forest, Little Belt Mountains, Montana

Research – Historical and Present

Aerial photo of thinning treatments imposed in the Sun Creek drainage.
Aerial photo of thinning treatments imposed in the Sun Creek drainage.
Since 1991, research at Tenderfoot Creek develops and evaluates methods for sustaining east-side lodgepole pine communities’ productivity and biodiversity. Recent studies at the Tenderfoot Creek Experimental Forest include forest monitoring and health, spatial fuel analysis, hydrologic processes including water quality, sediment transport and discharge, climate and sustainable silviculture methods.

The Forest Service developed the Tenderfoot Research Project to take a multi-disciplinary approach to evaluating ecosystem-based treatments in lodgepole pine stands. Treatments will serve as demonstration sites where the public can view new management alternatives.

Objectives for the Tenderfoot Research Project are to:

  • Evaluate and quantify the ecological and biological effects of alternative silvicultural treatments and prescribed fire in lodgepole pine forests by creating reserve stand structures that emulate those created by natural disturbances;
  • Evaluate damage to reserve trees relative to alternative stand densities and structures and examine regeneration and understory vegetation changes associated with alternative silvicultural treatments;
  • Develop linkages between vegetation management activities and hydrologic responses at the sub-watershed level;
  • Manage and integrate the knowledge gained from the variety of studies at Tenderfoot Creek Experimental Forest to improve ecosystem-based management in lodgepole pine forests;
  • Develop demonstration sites for education of the general public, students, professional, and researchers;
  • Test and verify hydrologic and vegetation models and evaluate harvest costs and product recovery values associated with alternative silvicultural prescriptions and harvest systems;
  • Contribute to the scientific knowledge through publication of results in appropriate outlets; and
  • Integrate knowledge gained from these studies into ecosystem management guidelines (see Management guide to ecosystem restoration treatments: two-aged lodgepole pine forests of central Montana, USA) that enhance the function and sustainability of lodgepole pine forests in the Northern Rockies through a variety of technology transfer products.


Image: TCEF gridded plot locations
TCEF gridded plot locations
A set of tenth-acre fixed area plots have been established on a 330-m grid across the Tenderfoot Creek Experimental Forest (TCEF) to monitor changes in vegetation and fuel dynamics over large spatial and temporal domains.

Most ecological studies fail to account for ecosystem response and its variability over large space and long time scales. Impacts of many disturbances and management actions, such as climate change, mountain pine beetle outbreaks, timber harvesting, and wildland fire, must be studied across large areas to ensure the scale of the disturbance match the scale of analysis, and they must be studied for over long time periods to ensure all ecosystem responses are detected. The Tenderfoot Creek Experimental Forest (TCEF) Grid project was designed to establish a set of gridded plots across the TCEF to monitor changes in vegetation and fuel conditions.

From 1996-98, we established 319 permanent plots arranged in a 330-m grid across the TCEF. Our initial collection efforts captured the biophysical setting, location, plant composition, and surface fuel data based on the Ecosystem Inventory and Analysis Guide, 1972.

In 2008, amidst an increase in mountain pine beetle activity in the area, we began resampling the plots. This effort was finalized in 2012 with funding from the US Forest Service, Forest Health Protection, Ecosystem Health Program. This 2008-12 effort included collection of surface fuel, vegetation, and tree data. Overstory tree (n=11,361) data included species, diameter at breast height, health status, canopy position, crown base height, and tree height. We examined every pine tree (n=9,500) for evidence of beetles and assigned a beetle class. For dead pine trees, we assigned both a beetle class and a snag class based on the state of decay/estimate of time since death. Other tree data was collected for saplings (n=17,182) and seedlings (n=871).

This gridded network of plots allows scientists interested in studying lodgepole pine forests a unique resource of vegetation and fuel information re-measured after a 15-year interval over a large spatial extent.

Long-term Monitoring and Data

Recording stream flow on Upper Sun Creek.
Recording stream flow on Upper Sun Creek.
Researchers established hydrologic and climatologic monitoring sites in the early 1990s to record environmental effects of various silvicultural methods used to restore and regenerate healthy lodgepole pine forests. Long-term data sets include stream flow, sediment flow, annual precipitation, and water quality data collected on Tenderfoot Creek and several major sub-watersheds of Tenderfoot Creek. Access to these data is available on the Forest Service Research Data Archive.

Facilities Information

Measuring snowpack at Tenderfoot Creek Experimental Forest.
Measuring snowpack at Tenderfoot Creek Experimental Forest.
To access the experimental forest, turn west on to USFS Forest Road 839 located just north of Kings Hill Pass on US highway 89. From the turnoff on highway 89, it is approximately 12 miles (20 km) to the eastern boundary of the experimental forest.

Permanent structures at the Tenderfoot Creek Experimental Forest include 10 hydrologic flumes and one open-channel measurement site. These flumes measure stream flow on Tenderfoot Creek and seven sub-watersheds flowing into the headwaters of Tenderfoot Creek.

The National Resource Conservation Service maintains two snow telemetry (SNOTEL) sites located in Onion Park and at the base of Stringer Creek.

The Duke University hydrology lab maintains two H2O/CO2 eddy-covariance towers, one near Dry Park and another in the Spring Park Creek sub-watershed.

Other features include internal access roads for stream monitoring (Tenderfoot Creek and Lonesome Creek) and for access to new research. All other roads are within or on the border of three of the four boundaries of the Tenderfoot Creek Experimental Forest. The western boundary is accessed by trails only. The main road along Tenderfoot Creek is closed to motorized vehicles except for administrative use. 

Research Opportunities

Opportunities for research at Tenderfoot Creek abound for those interested in evaluating new techniques and options for managing lodgepole pine communities in the Northern Rocky Mountains. Possibilities include fuels management, plant response and development following harvesting, prescribed burning, water production, water quality, and associated ecological processes.

The Experimental Forest & Range Network encourages re-use of the data collected by its members. We also recognize the importance to our participating scientists of receiving proper credit for the contribution their data make to other projects. It is also important to both our scientists and to Forest Service Research & Development that we understand who is using the EFR Network data. The scientists use this information in their performance reviews; FS R&D uses it to guide decisions on allocation of resources (e.g., to web-based access to data, re-packaging of data products for particular audiences, etc.) and for its performance review with Congress. Therefore, most EFR Network research data are covered by a data use agreement. If you are familiar with the Long Term Ecological Research network, you will notice that this agreement has been modeled on their agreement. Please note that the Network does not judge the quality or appropriateness of the data use you as a potential user of our data describe in the agreement.