Fire Following Plants

Most people know that our ecosystem is renewed by fire, but they may not be aware of the details. Researchers have found that different species of plants use different components of fire. Some species need the heat to germinate their seeds, some depend on the chemicals in smoke. Others take advantage of the openings in the vegetation that a fire creates. Still others are specialists that appear after a fire, multiply for a few years, then vanish until the next fire occurs. Mary Bowerman described the phenomenon of fire-following flowers in her 1944 book on Mt. Diablo's plants. These species tend to grow in colonies so they make quite a display.

The picture at the top shows an example of this phenomenon in Lime Ridge involving two species – chaparral or slender sunflower (Helianthus gracilentus) and Hall's bush mallow (Malacothamnus hallii). It is on the edge of the area where a fire occurred in 2003 and was probably at its peak when these pictures were taken in June 2006. These plants were growing in an open spot at the edge of a large chaparral patch, along with black sage, monkey flower, and yerba santa. There were two other patches on that hillside. The smallest patch had faded away by 2011. In the next two years the others also showed significant decline. In the normal course of events, it will be 30-40 years before another fire occurs and brings them back.

Close up of Slender Sunflower

Close up of bush mallow

Lesley Hunt
June 2006 & January 2013