August 19, 2009
 | |
Even though this fire burned primarily Sierra Nevada pine forest and chaparral, which is a more fire-prone landscape than coastal redwood, there may be some interesting lessons to be learned for coastal forest managers.
| ||
The ARC Fire provided a unique opportunity to review, first hand, the impacts of various forms of fuel management aimed at reducing impacts of fire, as several areas that burned had undergone previous fuel treatments. Those areas were primarily pine plantations where understory shrubs had been masticated, and mature forest stands where commercial thinning had taken place.
Two basic conclusions were drawn from this study:
1. Mastication does not remove fuels from the site, but redistributes them. It reduces ladder fuels, but in so doing, increases surface fuels. Until those masticated fuels decompose, they actually provide an extensive layer of easy-to-ignite kindling, fuels which are much more likely to ignite and burn than live fuels, otherwise known as living plants.
Live shrubs and hardwoods were actually resistant to burning. Safford stated that, "the fact that these masticated units performed so poorly under early season conditions suggests that caution should be used in their implementation, especially in areas of long summer drought like the Sierra Nevada."2 The ARC report cites several studies which actually found that mastication either "support[s] the highest rates of spread, fireline intensities, flame lengths, and levels of tree mortality" or "result[s] in 95% tree mortality under only 80th percentile weather conditions."3
2. Only one of the forest thinning treatments performed completely as designed. All the rest of the fuel treatments in the mature forest experienced moderate to severe fire effects. The exception was the only treatment where both reduction and removal of surface and ladder fuels had apparently been accomplished. 4
The report cites several studies which noted that crown thinning alone is not likely to meaningfully change potential fire behavior or effects and adds that the events of the American River Complex fire support those findings.5
Having attended a Board of Forestry field trip just last year to view a mastication `showcase' treatment outside of Marysville, it appears that practice still needs to catch up with science. Relatively new Board of Forestry rules allow for conducting thinning, mastication and other such fuel treatments under exemptions from the Forest Practice Rules, with little to no agency oversight. Such exemptions allow for harvesting a number of larger trees to pay for these fuel treatments. If surface fuels are allowed to remain, are these activities sufficient to slow down the spread of fire, or may they inadvertently exacerbate the problem?
While redwood forests are not nearly as prone to fire as pines, slash left after harvest activities has been modeled to show an increase in fire risk to the remaining stand.6
Fire is a powerful force. Young plantations and forests that have been heavily managed are more vulnerable to fire than their old growth counterparts. Getting fuel management techniques that work to `fire proof' forestlands, while meeting the economic requirements of landowners still seems to be in the experimental stage. Future forest survival along with those species that depend on healthy forests may require replacing short-term economics with a more long-term view. Science may have some of the answers already, but managers may need to change their perspectives and their programs.
As global warming alters the playing field for fire, landowners will need to get smarter faster.
Jodi Frediani became involved in forest and watershed protection in 1980 when 30 acres of old-growth redwoods were proposed for logging adjacent to her spring and fronting a half mile along Majors Creek in Santa Cruz County's Bonny Doon area. Through her efforts, that forest is now protected as state park land, and her spring continues to produce outstanding clean, clear water. Jodi has remained a strong voice for forest and watershed protection, focusing on timber harvest impacts, particularly those affecting old growth and riparian habitat. Jodi's column in FRN focuses on the effects of fire in forested ecosystems.
1 Safford, Hugh, Regional Ecologist, USDA-Forest Service, Pacific Southwest Region. "Fire Severity in Fuel Treatments, American River Complex fire, Tahoe National Forest, California, June 21--August 1, 2008." http://www.sierraforestlegacy.org/Resources/Conservation/FireForestEcology/FireScienceResearch/FuelsManagement/FM-AmRivComplex8-2008.pdf
2 Ibid, pg 20
3 Ibid, pg 20
4 Ibid, pg 20
5 Ibid, pg 21
6 Dicus, Christopher, Professor, Cal Poly San Luis Obispo, "Fuel Loading and Potential Fire Behavior After Selective Harvest in Coast Redwood Stands" ams.confex.com/ams/pdfpapers/69763.pdf
More Articles...
TOC for Forest & River News, Summer 2009