NATURAL FIRE REGIMES and PRE-EUROPEAN SETTLEMENT VEGETATION of the CHARLES M. RUSSELL NATIONAL WILDLIFE REFUGE Box 110 333 Airpo
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NATURAL FIRE REGIMES AND PRE-EUROPEAN SETTLEMENT VEGETATION OF THE CHARLES M. RUSSELL NATIONAL WILDLIFE REFUGE Report Prepared for The Charles M. Russell NWR U.S. Fish and Wildlife Service Box 110 333 Airport Road Lewistown, MT 59457 by Cecil C. Frost Landscape Fire Ecologist 119 Potluck Farm Road Rougemont, NC 27572 336-364-1924 (office) 919-906-1915 (cell) August 22, 2008 ACKNOWLEDGEMENTS Thanks are due to the staff of the refuge at Lewistown, and managers of Sand Creek, Jordan and Fort Peck. Thanks especially to Bob Skinner as my chief contact for questions, for discussions and for copies of refuge documents and published materials. Thanks go to Joann Dullum for producing the vegetation map and a GIS map of original habitats of prairie dogs in the CMR landscape, to Susan Langley for production of the fire frequency map on GIS, to Paul Pallas for help with assembling crews with equipment for collecting tree sections and for supplying information on fire records at CMR, and to Dan Harrell for field assistance and information on historical numbers of livestock in Montana. The Missouri Tree Ring Laboratory analyzed the historical fire scars in the first sections I collected form fire-killed trees and Michael Stambaugh and his father Phil Stambaugh came from the laboratory to CMR in 2007 to collect additional specimens to complete the fire scar chronologies. DISCLAIMER The findings and opinions expressed herein represent the interpretations and professional judgments of the author. These are not necessarily representative of the policies or opinions of The U.S. Fish and Wildlife Service. 2 TABLE OF CONTENTS Page Executive summary ................................................................................................................... 7 1) INTRODUCTION ............................................................................................................... 8 Reading the fire landscape......................................................................................................... 8 Field data ................................................................................................................................... 9 Historical vegetation .................................................................................................................. 7 Changes in vegetation since European settlement ................................................................... 10 Pre-European fire regimes ....................................................................................................... 10 Effects of the 2006 wildfires on old-growth Douglas fir and ponderosa pine ......................... 10 2) FIRE ECOLOGY OF THE PHYSICAL LANDSCAPE ................................................... 13 Firebreaks and fire filters......................................................................................................... 14 Geologic features related to firebreaks and fire filters ............................................................ 14 Firebreaks ................................................................................................................................ 16 Fire filters ................................................................................................................................ 16 Fire frequency versus fire severity .......................................................................................... 17 Native Americans as an ignition source .................................................................................. 18 Effects of topography on fire frequency .................................................................................. 20 Lightning as an ignition source ............................................................................................... 23 Ignition sources and fire movement ........................................................................................ 23 Lightning ignition fans ............................................................................................................ 24 27 year fire history – the actual distribution of ignitions ........................................................ 29 Implications for fire elsewhere in shortgrass prairie ............................................................... 32 3) FIRE RELATIONS OF NATIVE ANIMAL SPECIES .................................................... 33 Historical effects of beaver on fire frequency, species diversity and possible habitat for moose at CMR ................................................................................................... 33 Possible relationship between extirpation of beaver and decline of habitat for sharptail grouse ............................................................................................................... 34 History of beaver trapping in the CMR area ........................................................................... 35 Diversion of small stream water supplies for irrigation .......................................................... 39 Possible moose habitat maintained by beaver ......................................................................... 39 Effects of prairie dogs on fire frequency ................................................................................. 40 Mapping historical extent of prairie dogs towns as step in fire frequency mapping ............... 42 The reported historical prairie dog increase ............................................................................ 44 Effects of bison on fire frequency ........................................................................................... 45 3 Bison numbers ......................................................................................................................... 45 History of cattle and sheep grazing in the CMR area .............................................................. 46 The era of the big ranches 1880-1910 ..................................................................................... 47 Effects of cattle and sheep grazing on fire frequency ............................................................. 51 Fire spread in grazed and overgrazed prairie ........................................................................... 51 Effects of cattle ........................................................................................................................ 52 4) TIMBER USE AND FIRE ................................................................................................. 56 5) FIRE SCAR CHRONOLOGIES ........................................................................................ 57 Considerations in using fire scar chronologies for determining historical fire frequency ....... 57 Suggestion of a higher fire frequency in the pre-horse era ...................................................... 59 Buffalo grazing and fire – evidence from the fire scar record ................................................. 60 6) EVIDENCE FROM TREE DEMOGRAPHY PLOTS ....................................................... 62 Lost Creek ............................................................................................................................... 62 C.K. Creek ............................................................................................................................... 64 7) EVIDENCE FROM HISTORICAL PHOTOS AND OTHER FIRE HISTORY ............... 65 8) MAPPING PRE-EUROPEAN FIRE FREQUENCY IN SHORTGRASS PRAIRIE ......... 70 Fire exposed versus fire sheltered sites ................................................................................... 72 Some steps in mapping both pre-European settlement fire frequency and vegetation ............ 72 Making a relative fire frequency map ..................................................................................... 72 Drawing fire compartment boundaries .................................................................................... 73 Assigning fire frequency classes to fire compartments ........................................................... 74 Assigning fire frequency numbers to each fire frequency class .............................................. 76 Fire frequency classes – variation between original fire frequency before and after introduction of the horse to North America by the Spanish ................................................. 77 Descriptions of the nine fire frequency classes ....................................................................... 78 Skewness in fire frequency distributions ................................................................................. 80 Fire frequency in the pre-horse era .......................................................................................... 80 Considerations for using these tables for prescribed fire ........................................................ 81 9) CONCLUSIONS: results products the Answer to the Question “Is this natural?” .......... 82 Speculative conclusions deserving further study..................................................................... 83 Arguments for natural versus anthropogenic causes of the severe fires of July 2006 ............. 83 LITERATURE CITED ........................................................................................................... 84 APPENDICES APPENDIX 1. HISTORICAL VEGETATION AND FUEL TYPES OF THE CHARLES M RUSSELL NATIONAL WILDLIFE REFUGE 4 APPENDIX 2. METHODS APPENDIX 3. CHRONOLOGY OF SELECTED HISTORICAL EVENTS AT CMR