When a wildfire burns, burned tree snags are often the most noticeable feature remaining on the landscape.
Less apparent are effects to the plant species in the understory, many of which are forbs and shrubs that are adapted to promptly return to the post-fire landscape. In addition to assessing potential threats to life and safety, property and cultural resources during rain events following in burned areas, the Forest Service Burned Area Emergency Response program also assesses potential threats to natural resources, which includes an assessment of native plant communities.
Lassen National Forest botanist Kirsten Bovee and Plumas National Forest ecologist Michelle Coppoletta have been evaluating the risk of invasive plant introduction and spread in native plant communities within the Dixie Fire.
They are finding that mere weeks after the fire swept through the Highway 70 corridor, many native and invasive species are already resprouting. These include native willow along the North Fork of the Feather River but also invasive Himalayan blackberry.
Areas that have experienced multiple recent fires, such as the hillslope within both the Rich and Dixie Fire perimeters, are particularly susceptible to weed establishment and spread, due to full sun conditions and bare mineral soil exposed as litter and duff were consumed by fire.
The spread of invasive plants compromises native plant communities and all that they support — from fish, to mammals, to the life support of the fungal network underground, to trees, shrubs, and herbs.
Some native plants that are already making a reappearance on the burned landscape:
- Black oak, Quercus kelloggii, is sending up new stems from root crowns that continue to draw water and nutrients from the plant surviving in the below-ground root network.
- Caribou coffeeberry, Frangular purshiana ssp. ultramafica, is a rare shrub that grows only on serpentine soils in the northern Sierra Nevada.
- Beargrass, Xerophyllum tenax, lilies have protected their actively growing leaf tissue within rosettes of densely packed old leaves and have already added inches of new growth to the base of its leaves that burned during the fire. They will carpet the landscape with billowy clusters of white flowers in the years to come.
The Dixie Post-Fire BAER team botany assessments will prioritize high value and vulnerable native plant communities and result in proposed land treatments, such as an Early Detection Rapid Response strategy, to prevent the fire-related introduction and spread of invasive species.