Fire in the Trees
by Ken Mierzwa
The Marten - Newsletter
The Wildlife Society,
California North Coast Chapter, Spring 2003.
Prescribed fire in a northern flatwoods community, MacArthur Woods Nature Preserve, Lake County, Illinois
In November 2003, the North Coast Chapter of The Wildlife Society sponsored a fire ecology workshop. As we worked to organize this event, I've had an opportunity to review the status of our knowledge on woodland fire.
The early part of my ecology career was spent in the Midwest, where fire management is today taken for granted. One of my profs at Northeastern Illinois University was Bob Betz, the dean of prairie restoration, who had been burning at Fermilab since the 1960s. My first hands-on burn experience was at Braidwood Savanna in 1988. In the Chicago region, most of the remaining habitat has already been protected, but there are few large preserves. So the emphasis has long since shifted to management of the relatively small high-quality core areas, and restoration of buffer areas. Even there, the use of prescribed fire in wooded ecosystems has become common only in recent years.
My mid-1980s experience at the Angelo Coast Range Preserve in Mendocino County had led me to believe that fire issues were being addressed here, too; at least one graduate student had written about the fire regime within that old-growth system. But when I moved to the north coast for good about two years ago, it quickly became apparent that things were a little more complex.
There are ongoing prescribed fire programs in north coast National and State Parks. The Nature Conservancy is burning blue oak woodlands in the Lassen Foothills. Various other agencies have employed fire in selected locations. Harold Biswell used prescribed fire in Lake County as early as 1951. But at least in the past century, regional use of prescribed fire has generally been restricted to a small portion of the landscape.
Perhaps this is partially because of the much larger expanses of reasonably intact habitat - Humboldt Redwoods State Park is larger than some entire metro area suburbs - and the controversial nature of protection vs. resource extraction issues. Steep terrain, difficult access in some areas, unstable soils, and an ingrained fear of wildfire among many local residents further complicate the issue. The small regional population base also means that agency staff must conduct most burns (near urban areas, trained volunteers now do much of the burning).
Historic north coast fire frequency ranged from low in wet coastal systems to high in drier inland woodlands and chaparral. For thousands of years, Native Americans burned the landscape (for more on this, see the excellent article by Robin Wall Kimmerer and Frank Kanawha Lake in the November 2001 issue of Journal of Forestry). My preliminary attempts to tap into cultural knowledge have first met with surprise; they don't expect scientists to understand. Once reassured that we wish to learn, amazing bits of wisdom emerge. In Hoopa, where burning traditionally took place after the first fall rains, tribal elder Pliny McCovey told me that "spring is time to grow, fall is time to die." An Osage woman in Oklahoma once told a friend of mine "of course we burn. If we didn't the land would be useless, full of brush and ticks."
In redwood forests, where fire return intervals were relatively long, fire helped to maintain grassland openings which probably originated on landslides, and contributed to overall landscape-level diversity. Most reptile species, and a few types of amphibians, are more common in grassland openings than in nearby mature redwood/Douglas-fir forest.
There's a lot we don't know about how wildlife responds to burn regimes. It seems reasonable to assume that where fire was a regular part of the presettlement landscape, the wildlife assemblage must be adapted to fire. But with some invertebrates, fire is essential to maintain host plants while a too-extensive fire can damage vulnerable larvae. Patchy and low intensity fires work best in such situations.
There are issues of economic concern as well. Recent proposals to thin forests as a wildfire prevention technique are at best a short-term remedy, and they sometimes do not explicitly consider the needs of resident animals. Whether creating firebreaks or restoring habitat, humans tend to be impatient creatures. Addressing the effects of more than 70 years of active fire suppression will take time.
In the fall, we will come together to find out what we already know, and hopefully to learn where we need to go next. Certainly there are huge gaps in our knowledge. Quantitative studies are badly needed. For many types of animals, we can only infer probable effects from studies completed elsewhere.