Frijoles Canyon Tree Planting: Reforestation Efforts within the Las Conchas Fire Perimeter

Bianca Gonzalez prepares to carry a load of Douglas fir seedlings for planting in Frijoles Canyon

Photo credit: Carolina May

Bandelier National Monument’s Resource Management and Fire Ecology Programs are collaborating on a spring tree planting and monitoring project in Frijoles Canyon. Within the 2011 Las Conchas fire perimeter, the Frijoles Canyon landscape ranges from low severity burn areas with intact forest to areas that burned at high severity with no mature live trees remaining.

Planting trees in a three mile stretch of the canyon between Alcove House and Upper Crossing allows for data collection focused on growth and survival in a variety of environments. The data will be entered into a long-term ecological monitoring database, and the seedlings will be resurveyed by the Fire Ecology Program into the future. This project will provide information about the factors affecting seedling survival in Bandelier and will inform future planting efforts.

Carolina May uses a dibble bar to prepare holes for seedling planting in Frijoles Canyon

Photo credit: Bianca Gonzalez

Resource Management Intern Bianca Gonzalez and Fire Ecology Intern Carolina May conducted the planting and data collection from March 30^th April 16^th 2020. A total of 817 seedlings were planted as part of the monitoring project (426 ponderosa pine; 391 Douglas fir).

After the seedlings were planted, the following data were collected:

• location
• elevation
• species
• height
• canopy closure
• distance to mature trees
• photos were taken for documentation
• presence or absence of cover objects such as logs, rocks, or shrubs

Taking advantage of microclimates

Areas inside the Las Conchas Fire perimeter face a series of challenges to natural reforestation, including little to no canopy cover in high burn severity areas, rising temperatures, and a projected regional trend of increasing dryness (Haffey et al, 2018). These challenges can limit natural seedling regeneration, which prompted the identification of cooler, wetter "microclimates" within the broader landscape for some of the planting.

Figure 4. Douglas fir seedling planted on the north side of a “nurse log,” on the north facing slope of Frijoles Canyon

Bandelier. Photo credit: Carolina May

Previous research suggests that planting seedlings beside a fallen log , to be used as a "nurse log,” may allow for greater moisture retention and sun protection, increasing the survival rate of seedlings (Castro et al, 2011). Other cover objects, such as rocks or shrubs, were also used for planting sites.

When using a cover object, seedlings were planted on the north side to provide maximum sun protection throughout the day. Of the 817 trees that were planted, 386 were planted on the north side of a cover object, while 431 were planted without cover objects.

Bianca Gonzalez plants a Douglas fir seedling on the north side of a “nurse log,” Frijoles Canyon

Photo credit: Carolina May

Slope aspect is another factor involved in identifying hospitable microclimates for seedlings.

North facing slopes receive less direct sunlight and tend to retain more moisture than slopes with other aspects, therefore the majority of planting sites were selected on the north facing slope of Frijoles Canyon.

Variation in burn severity among planting sites

Planting sites were selected across a range of post fire environments, from unburned forest to high severity burn areas. Planting site selection also varied based on species; ponderosa pines were planted in upslope areas when possible, while Douglas fir were planted in close proximity to the stream and within the previous extent of the species. Fifteen Douglas fir and ponderosa pine sites were paired together, within 25 meters, to observe differential species survival
rates in similar environments.

Map of ponderosa pine and Douglas fir planting sites in Frijoles Canyon

High burn severity areas indicated in pink on the map are sites where the fire was intense enough to kill very tall mature trees. Moderate and low burn severity areas had less tree mortality. Seedlings were planted in areas with the most chance of survival and to re-seed areas where fire mortality has devastated the seed bank.

Left image
Ponderosa pine planting site on the edge of a low severity burn area in Frijoles Canyon
Credit: Photo credit: Carolina May

Right image
Ponderosa pine planting site in a high severity burn area with no mature living trees in Frijoles Canyon
Credit: Photo credit: Carolina May

Move the slider to see the dramatic difference between the impacts on mature trees during a low severity burn (left) versus a high severity burn (right). 

Tree Planting Sites by Species and Burn Severity

Ponderosa pine	0.0% (0/40)	42.5% (17/40)	17.5% (7/40)	40.0% (16/40)
Douglas fir	15.4% (6/39)	71.8% (28/39)	2.6% (1/39)	10.3% (4/39)
Total	7.5% (6/79)	57.0% (45/79)	10.1% (8/79)	25.3% (20/79)

The Fire Ecology Program will revisit planting sites for long term monitoring in future years and collect data on seedling height, health, and survival. This data will be used to further understand factors affecting seedling survival, determine environmental thresholds for replanting success by species, and inform restoration strategies for areas burned by the Las Conchas fire. As changing climate conditions continue to challenge natural seedling regeneration, this empirical data to inform human assisted reforestation projects will become increasingly valuable.

Data Collection Methods

Seedlings were planted in groups of ten per site. UTM/elevation data for each site were recorded on a Garmin Etrex 20x GPS unit. Canopy cover was measured using a spherical densiometer (average of N, E, S, W). Seedling height was measured to the nearest centimeter, and distance to mature living trees was estimated in meters. Cover objects were recorded if seedlings were planted on the north side and the cover objects were in contact with the ground. Species, seedling number, and observations on seedling health were also recorded. A photo encompassing all seedlings was taken at each planting site.

Figure 9. Bianca Gonzalez places trays in the stream to
moisten seedlings before planting in Frijoles Canyon

Photo credit: Carolina May

References

Castro, J., Allen, C.D., Molina‐Morales, M., Marañón‐Jiménez, S., Sánchez‐Miranda, Á. and Zamora, R. (2011), Salvage Logging Versus the Use of Burnt Wood as a Nurse Object to Promote Post‐Fire Tree Seedling Establishment. Restoration Ecology, 19: 537 544. doi:10.1111/j.1526 100X.2009.00619.x

Haffey, C., Sisk, T.D., Allen, C.D. et al. Limits to Ponderosa Pine Regeneration following Large High Severity Forest Fires in the United States Southwest. fire ecol 14, 143 163 (2018). https://doi.org/10.4996/fireecology.140114316

Contact: Laura Trader, Ecologist, Bandelier National Monument, [e-mail]