Whitmore Fire site in the Experimental Network for Assisted Migration and Establishment Silviculture (ENAMES)

The Whitmore Fire site after planting. The red pin-flags show the locations of the seedlings. Photo by Allison Philips.

Land manager: Confederated Tribes of the Colville Reservation.

Nearest town: Nespelem, WA.

Species: Ponderosa pine (Pinus ponderosa).

Site history: This site was historically a stand of ponderosa pine-bluebunch wheatgrass. While recorded history only goes back to 2008, management history over the past ~100 years likely included intermittent single tree selection and uneven age management treatments. In August of 2008, the nearly stand-replacing Columbia River Road Fire burned through the site, after which a large salvage operation removed 100 percent of overstory trees. The salvage operation coincided with a mast year for ponderosa pine cones, with reports of seed “falling like snow and covering the ground”, which created a “carpet” of regeneration trees estimated to be around 2,000 stems per ac. The site was scheduled for pre-commercial thinning in 2020, and in August of 2021 the Whitmore Fire burned through it, resulting in nearly 100 percent mortality of pine regeneration.

Whitmore Fire site 3D map showing experimental plots color-coded by the climate scenario each seed source is adapted to. Map by Laura Gonzalez Mantecon.

Site characteristics: The site is on a ridgetop at an elevation of 2,700 ft and faces south-southwest/north-northeast, with a gentle slope of 3–8°.  The soils are moderately deep, well-drained loams formed in mixed volcanic ash over glacial till. The mean annual temperature is 31 °F (coldest month: 13 °F; warmest month: 52 °F) and mean annual precipitation is 610 mm (384 mm of which is snow).

Planting date: Spring 2025.

Contact person:

Spus Wilder, Acting Assistant Forest Manager and Forester, San Poil Silvicultural District; Confederated Tribes of the Colville Reservation Forestry Department, Bureau of Indian Affairs.

Shay Logue, Lead Forester and Silviculturist; Confederated Tribes of the Colville Reservation Forestry Department, Bureau of Indian Affairs, Omak/Nespelem District.

Robert Slesak, Research Forester, USDA Forest Service, Pacific Northwest Research Station. 

The newly planted Ponderosa Pine at Whitmore Fire site. Photo by Allison Philips.

The forestry technicians taking first-year measurements on the tree seedlings. They measure the diameter, height, and take the geolocation of each seedling. Photo by Allison Philips.

Management objectives and other considerations: The main objective for this site is to re-establish a profitable timber stand, while maintaining other objectives such as soil stabilization and wildlife habitat recovery, as detailed in the Whitmore Fire Burned Area Emergency Response Plan and the Whitmore Fire Salvage Environmental Analysis.

Seedling survival in the Colville Reservation has been highly variable, particularly over the last ten years. Much of this variability can be tied to the amount of precipitation the year of planting and the elevation of the planting, with lower elevation showing higher levels of mortality. With changing climatic conditions, studies like these can help tease out trends and probabilities that will help us achieve overall higher survival rates in the future. Additionally, the planting of 2.5 million seedlings annually on the Colville Reservation has also put a strain on the workforce and nursery capacity. Historically, fairly large containerized seedlings (styro 10s) have been used; however, using smaller seedlings could greatly reduce the strain by increasing the amount of nursery growing space available and reducing the number of trips needed to bring seedlings to planting sites. The question we are hoping to answer is whether smaller seedlings have high enough survival rates that would justify a change in operational seedling stock type.

Site preparation: Site preparation will consist of piling conifer regeneration concentrations and scarifying ~50 percent of the ground with an excavator one field season before planned planting.  

Pre-planting site conditions: Before site preparation, the site is covered in nearly 2,000 dead stems of pine regeneration per ac.  Minimal grasses, forbs, and brush have reoccupied the site since 2021. While other nearby sites are successfully being planted in these conditions, they would hamper the ability for the study site to be analyzed, hence the need for site preparation. Next to no natural recruitment is expected due to the lack of potential parent trees nearby.

Experimental design: A randomized complete block with four replications per treatment applied to 0.5-acre plots.

Assisted migration treatments: The team used the Seedlot Selection Tool to choose four planted seed sources (see table below). 

Seed source locations matching historical and predicted future climates for the Whitmore Fire site. Map by Scout Dahms-May.

Silvicultural treatments: Three different stock types (see below).

Planting density: Operational contract crews will plant 300 trees per ac.

Seedling stock type: Containerized stock (Styro 6, Styro 10, ellepot).

Monitoring: The site will be monitored to track and compare seedling survival among seed sources and silvicultural treatments. Measurements are planned for 1, 5, 10, and 15 years after planting.

The site may also serve as a demonstration plot for managers to visit and visually compare seed source performance.