United States Department of Managing Sierra Nevada Forests Agriculture Forest Service Pacific Southwest Research Station General Technical Report PSW-GTR-237 March 2012 D E E P R A U R T LT MENT OF AGRICU 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