Restoring Composition and Structure in Southwestern Frequent-Fire Forests: a Science-Based Framework for Improving Ecosystem Resiliency
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Restoring Composition and Structure in Southwestern United States Department of Agriculture Frequent-Fire Forests: Forest Service Rocky Mountain A science-based framework for Research Station improving ecosystem resiliency General Technical Report RMRS-GTR-310 September 2013 Richard T. Reynolds, Andrew J. Sánchez Meador, James A. Youtz, Tessa Nicolet, Megan S. Matonis, Patrick L. Jackson, Donald G. DeLorenzo, Andrew D. Graves Reynolds, Richard T.; Sánchez Meador, Andrew J.; Youtz, James A.; Nicolet, Tessa; Matonis, Megan S.; Jackson, Patrick L.; DeLorenzo, Donald G.; Graves, Andrew D. 2013. Restoring composition and structure in Southwestern frequent-fire forests: A science-based framework for improving ecosystem resiliency. Gen. Tech. Rep. RMRS- GTR-310. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 76 p. ABSTRACT Ponderosa pine and dry mixed-conifer forests in the Southwest United States are experiencing, or have become increasingly susceptible to, large-scale severe wildfire, insect, and disease episodes resulting in altered plant and animal demographics, reduced productivity and biodiversity, and impaired ecosystem processes and functions. We present a management framework based on a synthesis of science on forest ecology and management, reference conditions, and lessons learned during implementations of our restoration framework. Our framework focuses on the restoration of key elements similar to the historical composition and structure of vegetation in these forests: (1) species composition; (2) groups of trees; (3) scattered individual trees; (4) grass-forb-shrub interspaces; (5) snags, logs, and woody debris; and (6) variation in the arrangements of these elements in space and time. Our framework informs management strategies that can improve the resiliency of frequent-fire forests and facilitate the resumption of characteristic ecosystem processes and functions by restoring the composition, structure, and spatial patterns of vegetation. We believe restoration of key compositional and structural elements on a per-site basis will restore resiliency of frequent-fire forests in the Southwest, and thereby position them to better resist, and adapt to, future disturbances and climates. Keywords: dry-mixed conifer, ecosystem services, ecosystem processes and functions, frequent-fire forests, forest structure, ponderosa pine, restoration, species composition, spatial patterns AUTHORS Richard T. Reynolds is Research Wildlife Biologist with the U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, in Fort Collins, Colorado. He has investigated the relationship between the composition and structure of habitats and the demographic performance of apex avian predators in forested ecosystems for over 40 years. His recent research focuses on relationships between individual and population demographics of northern goshawks and the structure and composition of their habitats in ponderosa pine and dry mixed-conifer forests on the Kaibab Plateau, Arizona. He and his colleagues have written management recommendations for restoring the native biodiversity, food webs, and goshawk habitat in ponderosa pine and dry mixed-conifer forests. He received his B.S. degree in Life Science and M.S. degree and Ph.D. in Wildlife Ecology from Oregon State University. Andrew J. Sánchez Meador is the Program Director of Biometrics and Forest Management with the Ecological Restoration Institute and Assistant Professor of Biostatistics and Quantitative Ecology in the School of Forestry at Northern Arizona University in Flagstaff, Arizona. Andrew’s most recent research focused on: (1) quantifying how natural and anthropogenic disturbances shape forested ecosystems; (2) application of spatial statistics to characterize individual tree-, stand-, and landscape-scale patterns; (3) using state-transition- modeling to examine factors influencing treatment effectiveness and longevity; and (4) applications of remote sensing and computer vision techniques to quantify vegetation structure. He received his B.S. and M.S. degrees in Forestry from Mississippi State University and his Ph.D. in Forest Science from Northern Arizona University. James A. Youtz is Regional Silviculturist with the U.S. Forest Service, Southwestern Region, in Albuquerque, New Mexico. He has been involved with the practice of silviculture and fire management in Southwestern forests since 1983. His program management responsibilities include training and certification of silviculturists in forest ecology and silvicultural practices and transfer of best available science to other managers to develop and incorporate strategies for ecological restoration of forest resiliency into program and project plans for National Forests in the Southwestern United States. He also has extensive experience serving with the U.S. Department of Interior in post-fire emergency stabilization and rehabilitation throughout the continental United States. He received a B.S. degree in Forest Management from Northern Arizona University. Tessa Nicolet is the Regional Fire Ecologist with the U.S. Forest Service, Southwestern Region, in Payson, Arizona. She has been involved with fire ecology and fire management in the Southwestern Region since 2005. Her responsibilities include training, analysis, and transfer of best available science relating to fire and fuels management, fire ecology, fire regimes, fire analysis modeling, and restoring fire to fire adapted ecosystems for fire professionals across the Southwest. She received an M.F. degree in Forestry with emphasis in Fire Ecology from Northern Arizona University. Megan S. Matonis is a Ph.D. student with the Graduate Degree Program in Ecology at Colorado State University. She is also a Graduate Student Cooperator with the Science Integration and Application program at the U.S. Forest Service, Rocky Mountain Research Station, in Fort Collins, Colorado. Her dissertation research focuses on collaborative landscape-scale restoration of ponderosa pine and dry mixed-conifer forests along the Colorado Front Range and Uncompahgre Plateau. She received a B.S. degree in Natural Resource Management from Colorado State University and an M.S. degree in Forestry from Michigan State University. Patrick L. Jackson is Chief of Staff with the U.S. Forest Service, Southwestern Region, in Albuquerque, New Mexico. He led a Forest Service Team in the development of Desired Conditions for frequent-fire forests in the Southwestern United States that is being utilized in the Forest Plan Revision process. He also led the Regional Landscape-Scale Restoration efforts resulting in an ecological restoration strategy and program based on Desired Condition. He received a B.S. degree in Forestry and Range Management from Colorado State University and an M.S. degree in Watershed Management from the University of Arizona. Donald G. DeLorenzo is Director of the Wildlife, Fish, and Rare Plant program with the U.S. Forest Service, Southwestern Region, in Albuquerque, New Mexico. Don has over 35 years of natural resource management experience with the U.S. Forest Service. He is a certified Wildlife Biologist and has held the positions of Research Associate at New Mexico State University and Assistant Professor at Oregon State University. He received a B.S. degree in Agriculture (Wildlife Science emphasis), and an M.S. degree in Wildlife Science from New Mexico State University. Andrew D. Graves is a Forest Entomologist with the U.S. Forest Service, Forest Health, New Mexico Zone, Southwestern Region, in Albuquerque, New Mexico. He has worked in the forests of the upper Midwest, Alaska, and California primarily focusing on bark beetles in these systems. He has worked in the region as an Entomologist since 2010. His responsibilities include providing expertise for the Forest Health, Prevention, and Suppression Program; providing hazard tree training; and assisting public land managers with forest insect detection, identification, and disturbance mitigation. He received a B.S. degree in Forest Management and a Ph.D. in Forest Entomology from the University of Minnesota. i EXECUTIVE SUMMARY Many forest landscapes in the Southwestern United States (Arizona, New Mexico, southwest Colorado, and southern Utah) have become increasingly susceptible to large-scale, severe wildfire, insect, and disease episodes. As a result, these areas are experiencing altered plant and animal demographics, reduced structural and spatial heterogeneity of vegetation, reduced productivity and biodiversity, and impaired ecosystem processes, functions, and services. Increased susceptibilities are most evident in frequent-fire forests—forests that historically experienced frequent, low- severity fire, which in the Southwest include ponderosa pine and dry mixed-conifer forests. Changes to these frequent-fire forests largely resulted from unregulated livestock grazing around the turn of the 20th Century, logging, and human activities such as fire suppression, resource use, and infrastructure development. We present a management framework for improving the resistance and resiliency of frequent-fire forest ecosystems to severe disturbances. This is accomplished by restoring the characteristic vegetation composition and structure in these forests. Frequent-fire forests had a characteristic uneven-aged structure consisting of a temporally shifting mosaic of different aged tree groups and scattered individual trees in an open grass-forb-shrub matrix—a spatial and temporal