Historical wildland fire use: lessons to be learned from twenty-five years of wilderness fire management

PRINCIPAL INVESTIGATORS

Matthew Rollins, Landscape Fire Ecologist, LANDFIRE Technical Leader

Co-Investigators

Penelope Morgan, Scott Stephens

INTRODUCTION

The project took place in four large Wilderness areas in the western United States which encompass some of the most fire-prone forests in the western United States. Fire management programs in these diverse wilderness areas have been pioneering, both in terms of fire suppression and fire management. Early in the 1970s these areas adopted fire management plans (currently referred to as Wildland Fire Use, WFU) in which naturally ignited fires were allowed to burn under prescribed conditions. The two main goals of these management plans were mitigating fire hazard resulting from extended fire exclusion and restoring wildland fire as a natural disturbance process at broad scales.

There is much to be learned from this 25-year experiment in restoring natural fire regimes, yet the landscape-scale effects of WFU in these areas have been little studied. Extensive areas have burned multiple times in WFU treatments, resulting in the conversion of previously dense forests to more open park-like stands with understories of bunch grasses, bracken fern, and prostrate shrubs. Elsewhere, high intensity fires have opened holes in previously continuous canopies ranging in size from a few to thousands of acres. These large wilderness areas are ideal natural laboratories for understanding landscape-level effects of fire regimes, as well as the degree to which fire alone has restored or failed to restore historical forest patterns.

Quantifying the effects of specific types of fires is important for evaluating the potential effects of WFU on ecosystem integrity and fuel reduction. Different approaches have been used to evaluate the success of WFU programs. As one example, the National Park Service Fire Effects Monitoring program uses a plot based sampling scheme to evaluate a host of ecosystem characteristics, such as fuel accumulation and vegetation changes. The Fire and Fire Surrogates Study, a current research project at thirteen sites across the United States, is examining ecosystem effects of prescribed fire and mechanical treatments at the stand level. Little information exists, however, about the effects of prescribed fire programs at broad landscape scales.

GOALS AND OBJECTIVES

Our research project was designed to answer three major questions:

1. Are there thresholds in pre-fire stand structure in ponderosa pine/Douglas-fir forests that lead to undesired levels of canopy mortality in WFU operations?

2. How has the implementation of WFU Programs in these study areas affected the nature of fire spread over time?

3. How do landscape composition, structure, and function vary under different fire management strategies?

KEY RESULTS

To address these questions, we combined landscape-scale experimentation and simulation based on existing fire history databases (e.g., fire atlases), comprehensive field inventories, extensive existing GIS databases, and 25 years of well-documented WFU in these wilderness areas.

REFERENCES

Holden, Z. A., A.M.S. Smith, P. Morgan, M.G. Rollins and P. Gessler. 2005. Evaluation of novel thermally enhanced spectral indices for mapping fire perimeters and comparisons with fire atlas data. International Journal of Remote Sensing 26(21): 4801–4808.

Holden, Z. A. P. Morgan, M. G. Rollins, and G.R. Wright. 2006. Ponderosa pine snag densities following multiple fires in the Gila Wilderness, New Mexico. Forest Ecology and Management 221:140–146.

Collins, B.M., K. Maggi, J. W. van Wagtendonk, and S. L. Stephens. 2006. Spatial patterns of large natural fires in Sierra Nevada wilderness areas. Landscape Ecology, 22:545–557.

Collins, B.M and S.L. Stephens. 2007. Managing natural wildfires in Sierra Nevada wilderness areas. Frontiers in Ecology and the Environment 5: 523–527.

PROJECT STATUS

Successfully completed in 2007

FUNDING ORGANIZATION

Joint Fire Science Project