Challenging shrubland fire management

In the March issue of Frontiers in Ecology and the Environment, Max Moritz (University of California, Berkeley), Jon Keeley (US Geological Survey and University of California, Los Angeles), Edward Johnson (University of Calgary) and Andrew Schaffner (Cal Poly State University, San Luis Obispo) present research that challenges some of the assumptions for managing fire-prone regions. With “Testing a basic assumption of shrubland fire management: how important is fuel age?,” the authors suggest natural fire regimes, such as those found in southern California, are “more driven by extreme weather conditions” than age-related traits of the region’s plant life.

Examining the fire history of coastal and southern California shrublands, the group discovered that the majority of shrublands’ risk of burning was fairly steady, at about 2.7 percent each year.

“Historical fire patterns and quantitative measures of hazard therefore refute the common assumption that fire probabilities in shrublands are strongly driven by vegetation age, and that large fires are necessarily caused by a buildup of older fuels,” according to the study.

Of the ten sites surveyed, only the region near Santa Barbara, at the western end of the Santa Ynez Mountains, showed a marked increase in fire hazard as the fuel, the plants, grew older. These results may be due to regional differences. Despite foehn weather conditions occurring nearby (such as the Santa Ana winds), this region is much less strongly affected, according to researchers.

Their findings parallel those found in Australia, and are thus relevant for other fire-prone regions that face extreme weather conditions.

“We shouldn’t assume future climates which increase fuel loads will alter fire patterns,” say the authors. According to the group, “our results contradict the widely held belief that large wildfires in California shrublands are the direct result of unnatural fuel accumulation due to fire suppression.”

Several scientific reviews also appear in this month’s issue of Frontiers in Ecology and the Environment.

In “Tropical Forests and global warming: slowing it down or speeding it up?” Deborah Clark (University of Missouri, St. Louis) discusses the possible role of tropical forest on global carbon levels.

“Sugar maple and nitrogen cycling in the forests of eastern North America,” by Gary Lovett (Institute of Ecosystem Studies) and Myron Mitchell (SUNY CESF) considers how these trees could affect nitrogen movement from the soil into surface waters such as lakes, rivers and streams.

The review “Conservation genetics in the new molecular age,” by Robert Wayne (UCLA) and Phillip Morin (Southwest Fisheries Science Center) describes molecular genetic techniques and their applications to conservation biology and ecology.

The Ecological Society of America (ESA) is a scientific, non-profit, 8000-member organization founded in 1915. Through ESA reports, journals, membership research, and expert testimony to Congress, ESA seeks to promote the responsible application of ecological data and principles to the solution of environmental problems. ESA publishes four scientific, peer-reviewed journals: Ecology, Ecological Applications, Ecological Monographs, and Frontiers in Ecology and the Environment. For more information about the Society visit www.esa.org