Forest Restoration in the Tongass Why, How and Where
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Forest Restoration in the Tongass Why, How and Where The Wilderness Society & Southeast Alaska Wilderness Exploration, Analysis and Discovery Written by: Bob Christensen 2012 Cover Photo: Gap Treatment Site Gap Treatment Photo: Cover Tongass Forest Restoration Report The Wilderness Society and SEAWEAD a TablE OF CONTENts List of Figures ....................................................................................................... ii Preface ................................................................................................................. iii Gratitude ............................................................................................................. iv Brief Summary ..................................................................................................... 1 Key Findings ......................................................................................................................................................1 Introduction ......................................................................................................... 2 The Purpose of this Document ...................................................................................................................2 What is Ecological Restoration? ..................................................................................................................3 What Restoration is Not ................................................................................................................................4 Why do Ecological Restoration? .................................................................................................................5 The Setting ........................................................................................................... 6 Southeast Alaska .............................................................................................................................................6 The Tongass National Forest .......................................................................................................................7 Logging History ...............................................................................................................................................7 Key Contextual Elements..............................................................................................................................8 Techniques for Tongass Restoration ................................................................ 17 Goals and Objectives ....................................................................................................................................17 The Silvicultural Toolbox ............................................................................................................................18 Conventional Thinning .................................................................................................................................19 Ecological Restoration Techniques ..........................................................................................................22 Variable Density Thinning (VDT) ...............................................................................................................34 Strategic Planning ............................................................................................. 36 Collaboration ...................................................................................................................................................36 Ecological Assessment .................................................................................................................................38 Prioritization.....................................................................................................................................................42 Watershed Restoration Designs ................................................................................................................46 Action Plans, Implementation and Adaptive Management ............................................................49 Conclusion .......................................................................................................... 50 Take Home Message .....................................................................................................................................50 Restoration Rules of Thumb .......................................................................................................................50 Caveats and Challenges ...............................................................................................................................51 Case Studies .....................................................................................................................................................52 References .......................................................................................................... 53 Acknowledgements and Author Info ............................................................... 64 Tongass Forest Restoration Report The Wilderness Society and SEAWEAD i List OF FIGURES Figure 1. Google Earth view of Southeast Alaska. ................................................................................6 Figure 2. The Tongass National Forest .....................................................................................................7 Figure 3. Landscape scale impacts to highly productive forest types .........................................10 Figure 4. Fragmentation on Northern Prince of Wales Island .........................................................11 Figure 5. Visual key to the Size-Density model data ..........................................................................15 Figure 6. Logged conservation lands ......................................................................................................16 Figure 7. Productivity and tree canopy classes ...................................................................................20 Figure 8. Some common thinning prescriptions. ...............................................................................20 Figure 9. Girdling for snag creation. ........................................................................................................24 Figure 10. Unthinned vs. gapped ............................................................................................................31 Figure 11. Comparison of spaced thinning to variable density thinning with SVS ..................34 Figure 12. A closer look at the SVS representation of a basic VDT prescription ........................35 Figure 13. Strategic Plan. ..............................................................................................................................36 Figure 14. Graphical representation of the GIS model of restoration needs .............................38 Figure 15. Watersheds identified by the restoration needs model ...............................................39 Figure 16. Watersheds’ cumulative restoration needs for Southeast Alaska .............................41 Figure 17. Graphical representation of the GIS model to prioritize watersheds .......................43 Figure 18. Watersheds identified by the prioritization model ........................................................43 Figure 19. Prioritized restoration watersheds for Southeast Alaska ..............................................45 Figure 20. Common features of a watershed relevant to restoration ..........................................44 Figure 21. Graphical representation of watershed restoration priorities ....................................47 Figure 22. Example of key components of watershed restoration design .................................48 Tongass Forest Restoration Report The Wilderness Society and SEAWEAD ii PREfacE “I have read many definitions of what is a conservationist, and have written not a few myself, but I suspect that the best one is written not with a pen but with an axe.” - Aldo Leopold 1949 In 2005 I began work on the “Tongass Ground-truthing Project” with my good friends Richard Carstensen and Kenyon Fields. For three years we assessed the impacts of past and proposed log- ging on the Tongass National Forest with a blend of GIS analysis and field surveys. We explored much of the Tongass and published reports that looked at the long-term effects of old-growth logging. Many of the findings were validations of what environmentalists had feared in watersheds “hammered” by the timber industry. As important as I believe this kind of monitoring was (and continues to be), the most profound things we learned pointed unexpectedly in another direction. This is best illustrated by our observations while walking streams and riparian forests heavily logged in the 1950s’-70s’; forests that had essentially been tilled and compacted by the tracks of skidders and the butts of giant logs. Much to our surprise, what we found in the watersheds we ended up calling the “hammered gems” were vi- brant and clearly valuable riparian habitats that continue to serve a globally significant abun- dance of salmon, bears, eagles, etc. Certainly to the eyes of forensic foresters and aquatic biolo- gists there was evidence of the long-term costs of industrial logging (esp. impacts to large wood recruitment for fish habitat), but there were also clear signs of nature’s capacity to adapt to cata- strophic disturbance and rapidly regenerate the diversity