Tamarack site in the Experimental Network for Assisted Migration and Establishment Silviculture (ENAMES)
The Tamarack Brush site, part of the Experimental Network for Assisted Migration and Establishment Silviculture (ENAMES) study, has been established in Bureau of Land Management’s land to test assisted population migration of Douglas-fir, Jeffrey pine, and incense cedar, as well as the effect of vegetation control on seedling survival and growth. The site burned during the 2020 Tamarack Fire and was planted in 2024.
A newly planted incense cedar seedling. Photo by Christopher Looney.
Landowner: Bureau of Land Management (BLM)
Nearest town: Markleeville, CA
Species: Incense cedar (Calocedrus decurrens), ponderosa pine (Pinus ponderosa), Jeffrey pine (Pinus jeffreyi)
Site history: The sites burned in the 2021 Tamarack Fire with salvage subsequently completed along a 400 ft buffer adjacent to an important access road to the local airstrip. Planted area was a mixture of salvaged and unsalvaged land due to a lack of stockable, salvaged areas.
Site characteristics: The sites are at an elevation of 5600 ft and generally face east with gentle slopes of less than 10%. The soils are Loamy-skeletal, mixed, superactive, frigid Typic Argixerolls. The mean annual temperature is 47 °F (coldest month 31 °F, warmest month 65 °F), and the mean annual precipitation is 582 mm (93 mm as snow). The sites occupy an ecotone between high-elevation mixed conifers: Jeffrey pine (Pinus jeffreyi), incense-cedar (Calocedrus decurrens) and white fir (Abies concolor), and woodland species: singleleaf pinyon (Pinus monophyla) and western juniper (Juniperus occidentalis).
Planting date: 2024
Contact person:
Jessica Wright, Research Geneticist, Pacific Southwest Research Station
Christopher Looney, Research Forester, Pacific Southwest Research Station
Post-planting at Tamarack site. Photo by Christopher Looney.
Pre-planting site conditions at the Tamarack site. Photo by Kara Sanghera.
Management objectives and other considerations: TBA
Site preparation: Sites were prepared with mechanical brush control localized around seedlings at the time of planting.
Pre-planting site conditions: Following salvage, sites had recovered a mixture of forbs and shrubs such as Ceanothus and Artemesia.
Assisted migration treatments: The team used the Climate-Adapted Seed Tool to choose four planted seed sources (see table below).
Ponderosa pine seed sources
Climate period
| Seed origin | Seed source elevation (ft) | Mean cold month temperature (°C) | Summer heat-moisture index |
Historical/local (1961-1990) | CA Seed Zone 732 (Lassen National Forest) | 3500-4000 | 0.76 | 223.5 |
Early-century (2011-2040) | CA Seed Zone 332 (Shasta-Trinity National Forest) | 2500-3000 | 2.87 | 233.0 |
Mid-century (2041-2070) | CA Seed Zone 321 (Klamath National Forest) | 1500-2000 | 2.48 | 276.0 |
Late-century (2017-2100) | CA Seed Zone 532 (Sierra National Forest) | 2000-2500 | 6.74 | 637.2 |
Jeffrey pine seed sources
Climate period
| Seed origin | Seed source elevation (ft) | Mean cold month temperature (°C) | Summer heat-moisture index |
Historical/local (1961-1990) | CA Seed Zone 781 (Toiyabe National Forest) | 5500-6000 | -0.78 | 197.3 |
Early-century (2011-2040) | CA Seed Zone 322 (Klamath National Forest) | 3000-3500 | 1.39 | 266.2 |
Mid-century (2041-2070) | CA Seed Zone 321 (Klamath National Forest) | 1500-2000 | 2.48 | 276.0 |
Late-century (2017-2100) | CA Seed Zone 532 (Sierra National Forest) | 2000-2500 | 6.74 | 637.2 |
Incense cedar seed sources
Climate period
| Seed origin | Seed source elevation (ft) | Mean cold month temperature (°C) | Summer heat-moisture index |
Historical/local (1961-1990) | CA Seed Zone 732 (Lassen National Forest) | 4000-4500 | 0.02 | 192.4 |
Early-century (2011-2040) | CA Seed Zone 322 (Klamath National Forest) | 2500-3000 | 1.50 | 290.7 |
Mid-century (2041-2070) | CA Seed Zone 526 (Eldorado National Forest) | 2500-3000 | 5.76 | 310.9 |
Late-century (2017-2100) | CA Seed Zone 994 (San Bernardino National Forest) | 2500-3000 | 7.14 | 559.1 |
Silvicultural treatments: Two vegetation control treatments: grubbing vs no grubbing.
Planting density: Contract crews will plant 302 trees per acre.
Seedling stock type: Half containerized, half bare-root stock (mixed at 50% each within each plot.)
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.
Year 1 results
In the graphs below, bars with same letter (for example, a) indicate no significant difference among seed sources/climate scenarios. Different letters (such as a vs b) indicate a significant difference based on latest measurements.
Figure 1. Seedling survival for the different seed sources 1 year after planting at the Tamarack site.
Figure 2. Seedling diameter by seed source 1 year after planting at the Tamarack site.
Figure 3. Seedling growth by seed source o1 year after planting at the Tamarack site.
Silviculture: Container seedlings had substantially higher survival rates than bare root seedlings, as well as increased height and decreased diameter. No species differences except decreased diameter in incense cedar.