United States Managing Sierra Nevada Forests Department of Agriculture Forest Service Pacific Southwest Research Station General Technical Report PSW-GTR-237 March 2012 DEPARTMENT OF AGRICULTEUR The Forest Service of the U.S. Department of Agriculture is dedicated to the principle of multiple use management of the Nation’s forest resources for sustained yields of wood, water, forage, wildlife, and recreation. Through forestry research, cooperation with the States and private forest owners, and management of the National Forests and National Grasslands, it strives—as directed by Congress—to provide increasingly greater service to a growing Nation. 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Editor Malcolm North is a research ecologist, Pacific Southwest Research Station, 1731 Research Park Dr., Davis, CA 95618. Cover photographs: (top) mixed-conifer forest with an active fire regime, by Marc Meyer; (middle, from left) regeneration in a forest gap, by Malcolm North; chipmunk on a log surrounded by shrub cover, by Brian Oakley; waterfall and pool in Sierra Nevada granite, by Malcolm North; (bottom) prescribed fire at Blodgett Experimental Forest, by Kevin Krasnow. Managing Sierra Nevada Forests Malcolm North, Editor U.S. Department of Agriculture, Forest Service Pacific Southwest Research Station Albany, California General Technical Report PSW-GTR-237 March 2012 Abstract North, Malcolm, ed. 2012. Managing Sierra Nevada forests. Gen. Tech. Rep. PSW-GTR-237. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 184 p. There has been widespread interest in applying new forest practices based on concepts presented in U.S. Forest Service General Technical Report PSW-GTR-220, “An Ecosystem Management Strategy for Sierran Mixed-Conifer Forests.” This collection of papers (PSW-GTR-237) summarizes the state of the science in some topics relevant to this forest management approach, presents case studies of collaborative planning efforts and field implementation of these new practices, and clarifies some of the concepts presented in GTR 220. It also describes a method for assessing forest heterogeneity at the stand level using the Forest Vegetation Simulator and a new geographic information system tool for project- level planning that classifies a landscape into different topographic categories. While this collection of papers presents information and applications relevant to implementation, it does not offer standards and prescriptions. Forest management should be flexible to adapt to local forest conditions and stakeholder interests. This report does, however, strive to clarify concepts and present examples that may improve communication with stakeholders and help build common ground for collaborative forest management. Keywords: Ecosystem restoration, forest resilience, heterogeneity, stakeholder collaboration. Preface Public forest-land management policy in the Sierra Nevada has gone through substantial changes over the last 20 to 30 years. Policies have tried to incorporate and adapt to public concerns on such issues as sensitive wildlife, high-severity wildfire, and changing climate conditions. Through the 1990s and first decade of the 21st century, Sierra Nevada forest management focused on either mechanical fuels reduction or minimal entry into and maintenance of California spotted owl (Strix occidentalis occidentalis) habitat. Recently, many of the 10 national forests in the Sierra Nevada began using concepts found in U.S. Forest Service General Technical Report PSW-GTR-220, “An Ecosystem Management Strategy for Sierran Mixed-Conifer Forests”1 (hereafter GTR 220) as a foundation to plan and implement projects. Summarizing recent scientific research, GTR 220 suggested revising management practices to actively integrate the provision of wildlife habitat and ecosystem restoration with fuels reduction. The GTR emphasized increasing forest heterogeneity at fine (within-stand) and large (across-landscapes) scales using topography as a guide for varying treatments. It also emphasized the ecological importance of fire, the need to retain suitable structures for sensitive wildlife, and locations where ecosystem restoration might involve thinning intermediate-sized trees. In the initial GTR, the focus was on developing the concepts of ecosystem management for the Sierra Nevada. A second edition of the GTR published in 2010 added an addendum addressing some of the issues frequently raised by forest managers. Translating GTR 220’s concepts into management practices required innovation in collaboration, planning, and implementation. Over the course of many field visits to projects implementing GTR 220 concepts, it became clear that some information gaps still persist, including science summaries of typically problematic topics most projects need to address, conditions that fostered successful stakeholder collabora- tion, tools for assessing forest heterogeneity, and project examples of GTR 220 implementation and marking options. This GTR is an effort to respond to those needs. The first section provides a summary of recent research in areas that managers have requested and addresses a specific suite of topics that affect fuels and forest restoration treatments and wildlife habitat in lower and mid-elevation Sierra Nevada forests. Topics include (1) fire and fuels reduction and whether current fire models 1 North, M.; Stine, P.; O’Hara, K.; Zielinski, W.; Stephens, S. 2009. An ecosystem manage- ment strategy for Sierran mixed-conifer forests. 2nd ed. with addendum. Gen. Tech. Rep. PSW-GTR-220. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. 49 p. can simulate fire response to the fine-scale heterogeneity suggested by GTR 220; (2) bark beetle dynamics—their potential response to different stand structures and how beetles may respond to increased variability in stem density and species composition; and (3) current and future impacts of climate change on Sierra Nevada forests and how important it is to understand the processes shaping historical forests to better manage ecosystems in an uncertain future. The second section focuses on aspects of wildlife management affecting Sierra Nevada forests. It includes (4) the latest research about two species of concern in lower and mid-elevation forests—fisher and marten; (5) a summary of California spotted owl research that has accumulated since Verner et al. (1992); and (6) some principles of managing for wildlife communities with variable scales, different pre- ferred habitat conditions, and often-unknown responses to management practices. The next section examines tools that can aid project implementation such as (7) building collaboration and (8) stakeholder involvement. Also addressed are (9) tools for increasing forest heterogeneity at the stand level with general marking guide- lines and using the Forest Vegetation Simulator to assess structural heterogeneity in treated stands; and (10) at the landscape level using a geographic information sys- tem (GIS) tool developed to classify project landscapes into different topographic categories, which might merit different forest treatments. The next section focuses on implementation, presenting case studies of projects that have used GTR 220 concepts. It details how the concepts in GTR 220 were (11) translated into project design and marking in the Dinkey North and South project on the Sierra National Forest; were (12) similar to the variable density thinning study at Stanislaus-Tuolumne Experimental Forest; and (13) used in drier eastern Sierra forests on the Sagehen Experimental Forest to meet fuels reduction, forest restoration, and marten habitat improvement objectives. The final summary sections clarify some GTR 220 concepts and address topics that appear to currently limit management options. Chapter 14 addresses under what conditions GTR 220 concepts apply; what characteristics identify “defect” trees with wildlife value; how canopy conditions can be more accurately assessed given the current standards and guides emphasis on canopy cover targets; and how heterogeneity may influence forest resilience and how it might be assessed. The final chapter (15) suggests changes that may be needed to insure that progress made with GTR 220 continues. Reflecting on lessons learned from field project visits and from these compiled chapters, this last chapter discusses how silviculture practices can adopt principles of heterogeneity, economic constraints and the scale of treat- ments, and the scientific merit and collaborative importance of committing to question-driven monitoring. Forest Service managers in the Sierra Nevada have repeatedly mentioned two concerns with GTR 220. The first is an apprehension that practices suggested in the There is an apprehen- ecosystem management strategy are too time consuming, expensive to implement, sion that practices difficult for marking crews to interpret, and involve lengthy and costly forums suggested in the for public involvement. The examples in these chapters suggest that such hurdles ecosystem management appear larger than they really are. With any new forest management strategy, strategy are too time initial implementation will be slower and more complex than current practices. consuming, expensive This approach, however, offers a set of ecological restoration principles that are to implement, difficult grounded in the latest research findings. Adoption of these principles may help for marking crews to build the trust and transparency necessary before more streamlined projects are interpret, and involve attempted. Future workshops and information exchange could help managers com- lengthy and costly municate what worked and what did not, and avoid each project having to “reinvent forums for public the wheel.” I hope that what is presented in these chapters will help shorten the involvement. The learning curve for all of us. examples in these A second concern is balancing the need to clarify concepts while retaining chapters suggest management flexibility. Although managers have requested more detailed definition that such hurdles of GTR 220’s concepts, there is also wariness that this detail will lead to prescrip- appear larger than tive guidelines that could constrain management practices. This collection of they really are. papers, however, is not a prescriptive guide or a set of standards for ecosystem man- agement. Rather it provides examples and information on lessons learned so far, as well as relevant science summaries. Each manager will need to find their own route to implementation that responds to the forest conditions and public constituencies they have. Best management practices require a flexible response to local conditions and needs. Helping to return that flexibility and “art” back to forestry is the essen- tial hope of this second GTR. For stakeholders to support this flexibility, however, there needs to be a common conceptual foundation for understanding how manage- ment decisions will be made and how we subsequently learn from the attempts to implement these new approaches. This collection of papers attempts to clarify that conceptual foundation and provide tools and examples of GTR 220 implementation. Contents 1 Chapter 1: Fire and Fuels Reduction B.M. Collins and S.L. Stephens 1 Introduction 1 Modeling Considerations 4 Landscape Fuel Treatment Design 7 Mixed Fire Severity Across Landscapes 9 Literature Cited 13 Chapter 2: Forest Health and Bark Beetles C.J. Fettig 13 Introduction 13 Host Tree and Bark Beetle Dynamics 14 Factors Associated With Bark Beetle Infestations 15 Managing Stand Density to Reduce Susceptibility to Bark Beetle Infestations 16 Implications of Climate Change on Bark Beetle Dynamics 18 Forest Heterogeneity and Bark Beetles 19 References 23 Chapter 3: Climate Change and the Relevance of Historical Forest Conditions H.D. Safford, M. North, and M.D. Meyer 23 Introduction 25 Recent Trends in Climate and Climate-Driven Processes in the Sierra Nevada 31 Projected Trends in Climate and Climate-Driven Processes 37 Is History Still Relevant? 39 References 47 Chapter 4: Fishers and American Martens K.L. Purcell, C.M. Thompson, and W.J. Zielinski 47 Introduction 47 Habitat Preferences 50 Forest Condition and Management Effects 51 New Analysis Tools 52 Potential Implications of Climate Change 54 Unknowns 56 References 61 Chapter 5: California Spotted Owls S. Roberts and M. North 61 Introduction 61 Population Trends 62 Barred Owl 62 Climate Change Effects 63 Spotted Owl Nesting and Foraging Habitat Characteristics 64 Spotted Owls and Fire 66 References 73 Chapter 6: Managing Forests for Wildlife Communities M. North and P. Manley 73 Introduction 73 Multispecies Habitat Management 74 Vertebrate Conservation and Fuels Reduction 77 Multiscale Monitoring 78 References 81 Chapter 7: Developing Collaboration and Cooperation G. Bartlett 81 Introduction 81 Dinkey Project History 83 Mediator’s Role 84 Five Stages of Collaboration 84 Steps That Facilitated Collaboration for the Dinkey Project 87 Additional Steps for Successful Collaboration and Cooperation 88 References 89 Chapter 8: Using GTR 220 to Build Stakeholder Collaboration C. Thomas 89 Introduction 89 Improved Communication 90 Sustainability 91 Perceived Problems 91 Challenges 91 Future Directions 92 References 95 Chapter 9: Marking and Assessing Forest Heterogeneity M. North and J. Sherlock 95 Introduction 96 General Marking Suggestions 97 Stand Visualization Simulator Examples 101 Using FVS to Assess Heterogeneity 104 References 107 Chapter 10: Geographic Information System Landscape Analysis Using GTR 220 Concepts M. North, R.M. Boynton, P.A. Stine, K.F. Shipley, E.C. Underwood, N.E. Roth, J.H. Viers, and J.F. Quinn 107 Introduction 108 Foundations for the GIS Tool 109 Background and Description of the GIS Tool 114 Chapter Summary 114 Literature Cited 117 Chapter 11: Dinkey North and South Project M. North and R. Rojas 117 Introduction 118 Context 118 Information Used 120 Implementation 121 Lessons Learned 124 References 127 Chapter 12: The Variable-Density Thinning Study at Stanislaus-Tuolumne Experimental Forest E. Knapp, M. North, M. Benech, and B. Estes 127 Introduction 129 Context 129 Information Used 132 Implementation 135 Lessons Learned 138 References 141 Chapter 13: Applying GTR 220 Concepts on the Sagehen Experimental Forest P. Stine and S. Conway 141 Introduction 141 Context 143 Information Used 144 Implementation 144 Lessons Learned 147 References 149 Chapter 14: Clarifying Concepts M. North and P. Stine 149 Introduction 150 Forest Types and Landscapes Where GTR 220 Concepts Apply 151 Defect Trees 152 Canopy Cover and Closure 156 Heterogeneity and Resilience 159 References 165 Chapter 15: A Desired Future Condition for Sierra Nevada Forests M. North 165 Introduction 165 The Limitations of Stand-Level Averages 167 Economics and Treatment Scale 169 Monitoring 172 Chapter Summary 172 References 176 Metric Equivalents 176 Acknowledgments 177 Appendix: Examples of Forest Structures That May Provide Wildlife Habitat D. Walsh and M. North