Vegetation Recovery at Point Reyes National Seashore Two Years Following the 2020 Woodward Fire

Parsons, Lorraine; Hendrickson, Rachel; Golding, Miriam

In summer 2020, Point Reyes National Seashore (Seashore) experienced its largest fire in 25 years. The Woodward Fire burned 4,841 acres, primarily within the Phillip Burton Wilderness. Before this, the most recent large fire in the park was the October 1995 Vision Fire, which burned 12,354 acres. While about 2,000 acres on the western side of the Woodward Fire had previously burned in the Vision Fire, the majority of the affected landscape had not burned in at least 75 years. To evaluate response of areas burned during the Woodward Fire, the Seashore implemented a field-based vegetation community recovery monitoring program in 2021-2022 that evaluated vegetation-related variables such as plant cover, species richness, and diversity, as well as seedling recruitment, basal regeneration, and plant damage (e.g., dead/damaged trees and shrubs). In 2022, approximately 35 permanent plots were established in the following communities: Hardwood Forest (8 plots), Douglas-fir (8 plots), Ceanothus (8 plots), Coastal Scrub (9 plots), and Bishop Pine (2 plots, not used in statistical analysis), with plots stratified to the extent possible to incorporate a range of fire frequency (e.g., once or twice burned) and fire severity based on BARC (Burned Area Reflectance Classification) ratings, which are derived from remote sensing. In general, total vegetation cover two years following the Woodward Fire was quite high, even though the first two years of recovery coincided with a drought. Vegetation response differed more based on estimated burn severity (BARC) than habitat. Only Coastal Scrub included a relatively even number of plots in once- and twice-burned areas, but burn frequency did not appear to influence vegetation recovery in this habitat. Total and native plant cover and native species richness were higher in scorched/very lightly burned areas than moderately or highly burned areas. In contrast to findings of other studies (Crawford et al. 2001, Hunter et al. 2006, Alba et al. 2014), neither severity nor habitat affected variables related to non-native plant species, with the exception of thistle cover, which was elevated in areas with higher burn severity. The highest native species seedling recruitment was observed in Ceanothus plots followed by Hardwood Forest ones, whereas basal sprouting proved the dominant form of regeneration in Coastal Scrub plots. Future monitoring efforts, both field- and GIS-based, will help to better inform about possible conversion to different vegetation communities or lifeforms.