During October 2006, the deadly Esperanza fire killed 5 people, destroyed multiple structures and burned over 40,000 acre (16,100 ha) of mountainous chaparral in Eastern Riverside County, CA. Shortly thereafter, we established a multi-level collaborative study to investigate relationships among fire behavior, chaparral age class, fire severity, and vegetation response. For this paper we compared plant data obtained from 0.12m 2 soil seed bank samples to the distance of the sample site from the nearest passable road. Soil seed bank samples were collected from 15 locations at 2 depths (0-2.5cm & 2.5-5cm) from 64 randomly selected post-fire sites. They were then placed in flats with sterile soil in a greenhouse and watered. Over 80 plant Taxa germinated and over 13,000 plants were identified, counted, and removed from containers. Most of the species were native herbs although invasive grasses were present throughout. The number of seeds per plot were ranked by density < 100, <200, <300, <400 and >500. Plot locations ranged in distance to nearest road from less than 500 m to greater than 20,000 m. Data was analyzed to determine if the number of plants that germinated was influenced by the distance sample sites were from a functional road.
Results/Conclusions Thirty-one percent of the samples had 100 seeds or less germinate while only 8 percent had 500 or more. Numerous iterations run found no trends in the number of seeds that germinated and their distance from roads. Further comparisons of different burn intervals, germination and distance to roads also showed no pattern. In the general area of the Esperanza fire, early chaparral regeneration from multiple age burns does not appear to have been impacted by road access. Investigating other parameters such soil type, slope, or aspect may give insight into regeneration potential of this area.
