The "Out of Whack Index" Gives Insight into Fires

By Carol Flaherty

09/13/00 BOZEMAN, Mont. -

Researchers say the "Out of Whack Index" can help us understand why we're facing bigger and hotter fires than ever before.

            The tongue-in-cheek term refers to a useful tool: an index that compares how often fires have occurred in prehistoric times to those in historic times. The data comes from rings of both living and dead trees, which show the scars of fire and regrowth, The tree-rings and scars can be correlated with our historical calendar, explains Lisa Graumlich, director of the Mountain Research Center at Montana State University.

           Fires at Los Alamos were "10 cycles out of whack," says Graumlich. The area near there prehistorically burned every seven years or so, but by 2000 hadn't burned for 70 years -- or 10 cycles. By comparison, low elevation forests in the Northern Rockies were about five cycles out of whack before the start of the "big blaze" of 2000.

            The magnitude of "out-of-whack-ed-ness" gives a good idea why we're facing large, intense fires in the United States this year, and perhaps gives insight into how to avoid such fires in the future, says Graumlich.

            It also calls attention to what researchers don't know, says Andy Hansen, a researcher in MSU's Ecology Department who cooperates with Graumlich and others to better understand wildfire patterns.

          "The Yellowstone fires have been studied extensively, but we haven't studied the forests near where people are living, the ones that are burning this year," says Hansen.

            That's precisely what Graumlich and Hansen have teamed up to do under grants from NASA and USDA.

            "The work they have proposed is applicable not just to the scientific community but to land and resource managers both in the Department of Interior and in the Park Service," says Paul Dresler, executive director for the Department of the Interior's science board.

            The idea for this research started from photographs that looked like they showed expansion of the conifer forest in just that area where people are building the most -- the forest's "leading edge."

            "It looks like there has been two fundamental changes in forests," says Hansen. If you look at photographs from 1890 and 1970 and 1990, you see the change in forest type, from aspen to conifer, from grassland to conifer and from sage to conifer.

            "That's incredibly important when you consider the amount of fuel a conifer forest offers compared to grassland or aspen."

            "The second change is in the density of the conifer forests. We've gone from an open savanna-like conifer forest to very dense closed conifer stands."

            Hansen explains that in the settlement of the West, there are stories of people driving horse-drawn wagons through lodgepole pine forests.

            "The fires took out the small trees and there were widely spaced large trees. Now it can be difficult to walk through a conifer forest, let alone drive a wagon through," says Hansen.

            Hansen and Graumlich's study will quantify the rates of forest expansion between 1950 and 2000 using aerial photographs and satellite images.

            Understanding that expansion should help quantify the risk of future fire, perhaps warning people in time that they will have the option of minimizing wildfires on the lands they manage.

            Dresler says he's interested in what Hansen and Graulich learn about vegetative cover, fuel loads, wildlife habitat interactions.

            "These are all topics that our managers in Yellowstone National Park and the BLM have identified as critical issues of concern of them," says Dresler. "We're concerned about the long term sustainability of the climate system, and we look for what are the type of changes the forest may have in Yellowstone. Is the white bark pine likely to disappear from Yellowstone? The pine is a food source for grizzlies, so the vegetation shift would have potential significance for wildlife management, too."