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Boise Basin Experimental Forest

Scientist in Charge: 

General Description

Located near Idaho City, Idaho, the Boise Basin Experimental Forest was established in 1933 to study ponderosa pine management. This experimental forest has been the site of long-term research and data collection on fire, soils, habitat types, and vegetation trends. Current research opportunities include ponderosa pine restoration, the urban-rural interface, and recreation. Check out the Boise Basin Experimental Forest Brochure for more information.

Photo of a sign at the Boise Basin Experimental Forest.
Photo of a sign at the Boise Basin Experimental Forest.

Background Information and History

The Boise Basin Experimental Forest lies outside of the small town of Idaho City, Idaho, approximately 30 miles northeast of Boise, Idaho. Established in 1933 to study management of ponderosa pine (Pinus ponderosa), the experimental forest consists of 8,740 acres (3,540 ha) divided into three units—Bannock, Bear Run, and Headquarters—surrounding the city. Bannock Creek contains old ponderosa pine with younger Douglas-fir in the understory. Bear Run is a younger ponderosa pine climax forest, with trees that are 80 to 100 years old. The Headquarters unit contains the old headquarters facilities, which are now administered by the Idaho City Ranger District. This small unit has a mixture of climax ponderosa pine and Douglas-fir. It also has ponderosa plantations that were terraced in the 1950s.

Idaho City was a booming mining town in the 1870s, and people took material from the surrounding forests. Mining caused major impacts on two units, and the majority of trees in them now are the result of post-mining regeneration. The third unit, on steeper slopes, has many undisturbed areas that contain large areas of ponderosa pine, including a Research Natural Area.


Sikkink, Pamela G. ; Jain, Terrie B. ; Reardon, James ; Heinsch, Faith Ann ; Keane II, Robert E. ; Butler, Bret W. ; Baggett, L. Scott. , 2017

Ecological Information

Warm, dry summers and cool, wet winters are the usual climate. Annual precipitation averages 25 inches (635 mm), with the most falling from October through June. Downpours and severe lightning can arrive in summer. Temperatures average 24.8 °F (-4 °C) in winter and 66.2 °F (19 °C) in summer.

Soils come from granitic rocks of the Idaho Batholith. They are generally deep and mostly Typic or Lithic Xeropsamments, Cryumbrepts, Cryoboralls, Cryorthents, and Cryocrepts with pH ranges from 5.5 to 7.0. The 50-year ponderosa pine site index ranges from 53 to 66.

Interior ponderosa pine dominates the forest cover at Boise Basin. Prior to successful fire exclusion, frequent surface fires maintained the pine with patches of quaking aspen. Douglas-fir occupies many settings, with mountain shrubs occupying the cooler aspects and shallow soils.

Research – Historical and Present

Photo of Terrie Jain, scientist-in-charge, at the Boise Basin Experimental Forest.
Photo of Terrie Jain, scientist-in-charge, at the Boise Basin Experimental Forest.
The earliest studies, beginning in 1933, evaluated different methods of selecting mature trees for harvest and the effects of remaining tree patterns on tree growth, reproduction, and understory plants. Crews installed permanent transects for monitoring tree reproduction and understory plants. Subsequent studies evaluated factors affecting germination, survival, and growth of young ponderosa pine, and the life histories of trees and understory plants in ponderosa pine forests. Researchers investigated competition factors for planted and natural pine seedlings in 1937. Two later studies examined seed storage, viability, germination, root systems of trees and seedlings, porcupine feeding relationships with ponderosa pine, and thinning and pruning methods.  Later studies of timber production compared using individual tree to group selection harvest methods; viability of seeds stored in soil; site preparation methods for tree planting; tree seed dispersal; applying plant hormones; and converting old-growth stands to second-growth.

Current activities include:

  • Developing practices to encourage integrated restoration in dry-mixed conifer forests
  • Investigating different methods to create more resilient ponderosa pine forests - such as forest floor treatments, mid-story treatments, and overstory canopy treatments - on more than 1976 acres (800 ha) on the Bannock unit
  • Investigating fuel treatments over time, including when and how they should be maintained
  • Studying tree response under different canopy openings
  • Studying long-term growth and stand development

Research on the Boise Basin Experimental Forest has included collaborators from the US Forest Service Intermountain Region (Region 4), the Boise National Forest, the National Interagency Fire Center, the University of Idaho, and Boise Cascade Corporation.

Research Accomplishments

Research at Boise Basin has provided important information on ponderosa pine management, habitat types in dry forests, ponderosa pine regeneration, and response of ponderosa pine to prescribed fire. Please contact the scientist in charge with questions about potential research opportunities or collaboration.

Long-term Monitoring and Data

Long-term databases on historical fire return intervals, soils, habitat types, and vegetation trends are available. Please contact the scientist in charge for more information.

Surface, Terrain, and Canopy Height Models

These data publications each contain three raster datasets with a spatial resolution of one meter: 1) a digital surface model (DSM), which represents the highest lidar return in each grid cell; 2) a digital terrain model (DTM), a representation of the ground surface with vegetation and other non-ground returns removed; and 3) a canopy height model (CHM), a representation of the height of vegetation above the ground surface. 

Facilities Information

Although they are sited within the experimental forest boundaries, facilities on Boise Basin are administered by the Idaho City District. The experimental forest is located about 30 miles (50 km) northeast of Boise, on Highway 21.

Research Opportunities

The Boise Basin has research opportunities related to ponderosa pine restoration, the urban-rural interface, and recreation. Please contact the scientist in charge for more information on research opportunities.

National Priority Research Areas: 
Watershed Management and Restoration