Workshop on the Multiple Influences of Riparian Ecosystems on Fires In
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WORKSHOP ON THE MULTIPLE INFLUENCES OF RIPARIAN/STREAM ECOSYSTEMS ON FIRES IN WESTERN FOREST LANDSCAPES SUMMARY REPORT By J. Boone Kauffman Department of Fisheries and Wildlife Oregon State University Corvallis, OR 97331 Presented To: Rocky Mountain Forest and Range Experiment Station Stream Systems Technology Center Fort Collins, CO 80526-2098 July, 2001 1 TABLE OF CONTENTS I. Introduction …………………………………………………………………3 II. Executive Summary…………………………………………………………4 III. Conceptual Relationships of Land/Water Use on Fire Behavior……………7 IV. Riparian Zones Defined…………………………………………………… 8 V. Summary Of Discussions And Responses to Questions…………………...10 VI. Workshop Outline/Script…………………………………………………..31 VII. Actual Responses to Questions ……………………………………………36 VIII. Appendices………………………………………………………………..201 Participant List…………………………………………………… 201 Introductory Essay by J.B. Kauffman …………….203 2 INTRODUCTION Riparian zones are among the most diverse, dynamic, and complex ecosystems on Earth. They are an interface between terrestrial and aquatic ecosystems. Their biotic composition, geomorphology, hydrology, microclimate, and fuel load, arrangement and chemistry are often much different than the surrounding uplands. As a result their fire regime (frequency, behavior, and biotic response) will differ. Riparian zones are often sites of increased natural disturbances (floods) while simultaneously functioning as buffers or barriers to other natural disturbances (i.e., natural fire breaks on the landscape). Riparian zones are frequently used in fire control and use activities. This includes their use as sources of water for suppression, as safety zones, and as control points and fuel/fire breaks. It could be hypothesized that land use activities that diminish pools in streams would indirectly increase the probability of deleterious wildfires in the surrounding landscape. In spite of the biotic, resource, and human values, few studies have investigated the role that riparian areas play in affecting the behavior and spread of fire on western forest landscapes. This report summarizes discussions from The Workshop On Multiples Influences Of Riparian/Stream Ecosystems On Fires In Western Forest Landscapes held at the Center for the Management of Information, University of Arizona, Tucson AZ, March 13-15, 2001. A diverse group of 30 federal scientists, fire and natural resource mangers, and university professors convened to discuss the functional role of riparian/stream zones as they affect fire on western forest landscapes (see appendix). Specific objectives of the workshop were to: (1) Discuss the status of knowledge on the relationships between fire and riparian zones at spatial scales from the riparian area to the entire landscape; (2) Discuss the role and values that riparian areas have for fire suppression and use; (3) Discuss the effects of land and water management on fire regimes (fire frequency, behavior and severity within riparian zones; (4) Discuss the effects of land and water management on the efficiency and capability of wildland fire control and use; and (5) Identify knowledge gaps and needed research on these subjects. To accomplish these objectives, the group participated in a series of verbal and electronic discussions over three days. The electronic discussions occurred using the GroupSystems software. The technical facilitator for the discussions was Ana Lopez (CMI) and the workshop coordinator was J. Boone Kauffman (Oregon State University). Prior to the 2 days of discussions at the CMI, workshop participants spent a half-day of initial discussions and presentations (see workshop outline). Each afternoon/evening was spent in illuminating discussions amongst informal groups hiking through the magnificent Sonoran desert. This report includes an executive summary and a summary of all discussions from the workshop. This is followed by the actual responses from the electronic portion of the workshop followed by appendices containing relevant documents generated from this workshop project. As the author of the report, I take full responsibility for the interpretations presented in the Executive Summary 3 and Summary of Responses. In these sections I endeavored to capture the sentiment of the workshop participants with as little bias as possible. All 30 participants statements are included in the section of actual responses to questions. EXECUTIVE SUMMARY A diverse group of 30 specialists in the fields of fire science, fire management, riparian ecology, hydrology and geomorphology met together for this workshop in Tucson, AZ on March 13-15, 2001. The goals of the workshop were: (1) discuss the status of knowledge on the relationships between fire and riparian zones at spatial scales from the riparian area to the entire landscape; (2) discuss the role and values that riparian areas have for fire suppression and use; (3) discuss the effects of land and water management on fire regimes (fire frequency, behavior and severity within riparian zones; (4) discuss the effects of land and water management on the efficiency and capability of wildland fire control and use; and (5) identify knowledge gaps and needed research on these subjects. A relevant summary is to present the final discussion of the Workshop where we derived the following 7 conclusions and polled the respondents for their level of agreement. Final Truths In this section, 7 conclusions that arose out of the discussions of the workshop were revisited to gage the degree of scientific agreement. Participants were asked to respond to the statements along a scale from strongly agree (5.00) to strongly disagree (1.00). If all respondents strongly agreed, the score would be a 5, and if all strongly disagreed, the score would be 1. Statements below are ordered based upon the degree of agreement (highest to lowest). The numbers before each statement are the means of the degree of agreement or disagreement of each statement. 4.58 Statement 1. While observations and intuitive knowledge would suggest that riparian zones are valuable for fire management and safety, we lack much quantification to address many needed resource management needs. There was strong agreement that we need more quantitative information on the functional role of riparian zones as they affect fire patterns on the landscape. 4.38 Statement 2. Riparian areas influence fire behavior/fire properties. However, we also recognize that fire is one of the natural disturbances shaping riparian stream ecosystems. This suggests a total fire exclusion policy in these areas (riparian zones) is unwise and unnecessary. It was recognized that the unique vegetation, microclimate, and topographic features of riparian zones function to affect fire behavior and spread. In many cases riparian zones have been effectively used in fire control and use. 4 In addition, it was recognized that fire is a natural disturbance process in riparian zones. As such, fire has a role in riparian zones and a total exclusion policy of fire is discouraged. It was recognized that other natural disturbances shape the composition and structure of riparian/stream ecosystems. In particular, floods or high flows are significant disturbances. Diversions which influence these processes also affect riparian structure and function. Alterations in structure and function could also affect the fire properties of the riparian zone. 4.23 Statement 3. Riparian zones and streams have some influence on the fire properties of forested landscapes It was recognized that riparian zones play an important role affecting fire on the landscape. Under some conditions, riparian/stream ecosystems act as fire breaks halting the spread of wildland fires on the landscape. In other cases riparian zones have been used by fire suppression forces as safety zones, burn out points, and water sources. These uses likely have resulted in fires of smaller area. 4.15 Statement 4. Riparian areas influence fire in the landscape where fuel moisture, loadings, composition and topography are different. This is true where fuels and microclimate may be strong controlling factors during fires. Under extreme weather events, fire behavior is largely influenced by weather variables. Comparing riparian zones to uplands, the unique presence of surface water, composition, fuel moisture, fuel chemistry, microclimate, and topography combine to affect fire behavior. There is a limit to the degree in which riparian zones affect fire behavior. Under conditions where fuel moisture is low (near or below the moisture of extinction) and under severe fire weather conditions (high winds, low relative humidity and high temperatures) riparian zones may burn with similar behavior as the uplands. 4.08 Statement 5. The long-term effect of land and water management (exclusion, water diversions, etc) can affect the function of riparian zones on the landscape. Fuel loads, vegetation composition, geomorphology and hydrology can be affected such that fire intensity/behavior is much greater than historically occurred under a similar weather scenario (“The Perry model”, Figure 1, Page 8). Water diversions can alter riparian/stream ecosystems such that the fuels, species composition, and microclimate become similar to uplands. Under these scenarios the differences in fire behavior between riparian zones and uplands are diminished. This would diminish their value in fire control as firefighter safety zones, and control lines. 4.00 Statement 6. Access to water sources is important in fire management activities (prescribed and wildland