Tracking the post-fire recovery of native plant communities on Land Trust preserves
The North Bay wildfires had a major impact on the Land Trust’s preserve network and land stewardship program, with four conservation properties totaling over 3,300 acres having burned entirely.
In the immediate aftermath of the fires, the Land Trust was focused on addressing concerns such as erosion risk, visitor safety, and damaged infrastructure and equipment.
In recent months, we have shifted our focus toward monitoring the ecological effects of the fires, with a particular emphasis on recovery of our fire adapted native plant communities.
The following photo essay highlights some of the amazing adaptations our native plants have developed to survive, and even benefit from wildfire. It also features some of the stunning species that we have observed thriving in recently burned areas.
Chaparral
Much of our post-fire botanical monitoring has focused on chaparral plant communities, which have been shaped by patterns of fire and contain many fire-dependent species. In contrast with many other plant communities, our chaparral is still dominated by native species as well.
Photo Plots
Establishing photo points has helped us to visually track the recovery of plant communities in burned areas over time. These photo comparisons from our Foote Botanical Preserve illustrate the dramatic recovery of our native chaparral species in just a few months following the fires.
Adaptations for Surviving Fire
There are two general strategies chaparral species utilize to survive fire, both illustrating how these plants have evolved with and adapted to fire as a source of natural disturbance.
- Resprouters have the ability to regenerate from surviving underground root systems following wildfire, even when all of the plant’s stems and leaves have been destroyed.
- Obligate seeders are killed by fire and rely entirely on regenerating from seed stored in the soil. The seeds of many obligate seeders require either exposure to chemicals in smoke or char, or a heat pulse generated by fire to stimulate germination.
Fire Followers
We have also been tracking species that are closely tied to the temporary conditions that exist for only a short period following a wildfire. We call these fire followers. Much of the baseline information on these species in Napa County comes from 40 years of careful study and documentation by professional botanist and Napa County flora expert Jake Ruygt. We have placed our fire followers into two general categories.
- Fire opportunists are typically present in low numbers in unburned areas. Following a wildfire, they dramatically expand their numbers, flower prolifically and quickly add to their seedbank while conditions are favorable. In some cases, these species have been found to flower only after a fire, even where the vegetative parts of the plant were present for many years before.
- Fire obligates are absent from an area for long periods, appearing only after a wildfire. The seeds of fire obligates require either exposure to chemicals in smoke or char, or a heat pulse generated by fire to stimulate germination. In addition, fire produces good conditions for germination of these species by releasing nutrients, clearing a bare mineral soil seedbed, and allowing light resources to reach the ground. Many fire obligates are observed for only the first year or two following a wildfire.
One of our most exciting fire obligate stories is the appearance of a large population of Fire Poppy (Papaver californicum) on the Foote Botanical Preserve following the Atlas Fire. Fire Poppy has not been observed in this area since the last time it burned…53 years ago!
Other fire obligates found on Land Trust preserves following the North Bay fires...
The Foote Botanical Preserve is also home to the largest known population of the rare, fire dependent Napa Ceaonothus (Ceanothus purpureus).
Our mature Napa Ceanothus were increasingly being outcompeted by other species as the time since the last wildfire event (in 1964) increased.
Our entire population of Napa Ceanothus burned in October’s Atlas fire. As of early March, we began seeing thousands of Napa Ceanothus seedlings. We have established monitoring plots to track their survival.