University of Montana ScholarWorks at University of Montana Graduate Student Theses, Dissertations, & Professional Papers Graduate School 2013 Variations in wildfire ash properties and implications for post-fire hydrological response within Western North American ecosystems Victoria Balfour The University of Montana Follow this and additional works at: https://scholarworks.umt.edu/etd Part of the Forest Sciences Commons Let us know how access to this document benefits ou.y Recommended Citation Balfour, Victoria, "Variations in wildfire ash properties and implications for post-fire hydrological response within Western North American ecosystems" (2013). Graduate Student Theses, Dissertations, & Professional Papers. 10742. https://scholarworks.umt.edu/etd/10742 This Dissertation is brought to you for free and open access by the Graduate School at ScholarWorks at University of Montana. It has been accepted for inclusion in Graduate Student Theses, Dissertations, & Professional Papers by an authorized administrator of ScholarWorks at University of Montana. For more information, please contact [email protected]. 1 VARIATIONS IN WILDFIRE ASH PROPERTIES AND IMPLICATIONS FOR POST- 2 FIRE HYDROLOGICAL RESPONSE WITHIN WESTERN NORTH AMERICAN 3 ECOSYSTEMS. 4 5 6 By 7 VICTORIA NAIRN BALFOUR 8 9 B.S., College of Charleston, Charleston, SC, 2002 10 M.S., University of Montana, Missoula, MT, 2007 11 12 Dissertation 13 14 presented in partial fulfillment of the requirements 15 for the degree of 16 17 Doctorate of Philosophy in College of Forestry, 18 Department of Ecosystem and Conservation Sciences 19 The University of Montana 20 Missoula, Montana 21 22 May 2013 23 24 Approved by: 25 26 Sandy Ross, Dean of The Graduate School 27 Graduate School 28 29 Dr. Scott W. Woods, Advisor 30 College of Forestry 31 (deceased) 32 33 Dr. Ron Wakimoto, Chair 34 College of Forestry 35 36 Dr. Andrew Larson 37 College of Forestry 38 39 Dr. Heiko Langner 40 Geosciences Department 41 42 Dr. Peter R. Robichaud 43 USDA Forest Service, Moscow, Idaho 44 45 Dr. Stefan H. Doerr 46 University of Swansea, Wales UMI Number: 3611845 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. UMI 3611845 Published by ProQuest LLC (2014). Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, MI 48106 - 1346 47 Balfour, Victoria, PhD, 2013 Ecosystem and Conservation Science 48 49 Variations in wildfire ash properties and implications for alterations in post-fire 50 hydrological response within western North American ecosystems. 51 52 Chairperson: Dr. Ron Wakimoto 53 54 Abstract: 55 56 Within the Rocky Mountain region of the Western U.S.A the average number of wildfires over 57 40 hectares have quadrupled and the frequency of large wildfires (> 4,000 hectares) have 58 increased seven times since the 1970’s. The effect of this increase on resource management and 59 ecosystem function is of increased interest to agencies and land managers within the region. The 60 research presented in this dissertation aimed to contribute to the growing knowledge of post-fire 61 hydrology, specifically with regards to the role of wildfire ash within recently burned 62 ecosystems. Ash should not be considered a generic term, as it is an important element of post- 63 fire landscapes, and should be categorized and taken into consideration when assessing post-fire 64 ecosystems and hazards. 65 The main findings of this research were that saturated hydraulic conductivity of ash spans three 66 orders of magnitude with some ash capable of decreasing an order of magnitude following initial 67 hydration. More specifically, the hydrologic response of low- and high-combustion ash can 68 prompt the formation of surface seals in post-fire systems by either creating a low conductive ash 69 layer or a chemical ash crust layer. Mid-combustion ash, on the other hand, acts as a capillary 70 barrier storing water thus explaining reported hydrologic buffering effects of ash layers. While 71 numerous authors have previously reported the presence of an ash crust within post-fire 72 ecosystems, this work is the first to document the formation of an in-situ ash crust within a 73 month after wildfire activity. The formation of an ash crust decreased ash hydraulic conductivity 74 by an order of magnitude, as well as significantly decrease ash layer bulk density and porosity. 75 While raindrop impact increased the strength of an ash crust, raindrop impact alone is not 76 sufficient to form an ash crust, instead mineralogical transformations must occur to produce a 77 hydrologically important ash crust. Therefore, initial ash composition, the presence of oxides and 78 a hydrating rainfall event are all necessary precursors for crust formation. The variations in 79 initial ash characteristics as well as temporal alterations indicate that ash layers should be 80 considered in modeling systems aimed at predicting post-fire infiltration response. 81 82 83 84 85 86 87 88 89 90 91 92 ii 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 ¤ COPYRIGHT 111 112 by 113 114 Victoria Nairn Balfour 115 116 2013 117 118 All Rights Reserved 119 iii 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 Dedicated to Dr. Scott William Woods 135 (October 4, 1966 - April 7, 2012) 136 137 138 139 From one Glaswegian to another, 140 141 “Farewell to the mountains, high-cover'd with snow, 142 Farewell to the straths and green vallies below; 143 Farewell to the forests and wild-hanging woods, 144 Farewell to the torrents and loud-pouring floods. 145 My heart's in the Highlands, wherever I go” 146 –Robert Burns 147 148 iv 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 "Try to learn something about everything and everything about something" 171 172 - Thomas H. Huxley (English Biologist 1825-1895) 173 v 174 Acknowledgements 175 176 This dissertation is dedicated to the memory of Dr. Scott W. Woods. Scott was a selfless, 177 caring man, with a driving love for education, science and exploration. He was a great mentor, 178 scientist, teacher and friend, who will be missed by many, but forgotten by none. It was a 179 privilege and honor to work with him for 8 years. He taught me more than he will ever know, 180 and above all the value of life and living your dreams. He was and always will be an inspiration 181 to me. 182 This research was funded by grants from the National Science Foundation (Award# 183 1014938) as well as the U.S.D.A. Forest Service Rocky Mountain Research Station (FSAN# 09- 184 CS-11221634-283). I am also thankful for the generous support and encouragement from the 185 following: Philanthropic Educational Organization (PEO) Scholars Award; College of Forestry 186 system of environmental management scholarship; International Association of Wildland Fire 187 (IAWF) scholarship, Montana Chapter of the American Water Resources Association 188 scholarship, University of Montana Graduate School Association, and the Bertha Morton 189 Fellowship. 190 I would like to thank my committee for their beneficial insight and comments towards the 191 completion of this degree; the late Dr. Scott Woods, Dr. Stefan Doerr, Dr. Ron Wakimoto, Dr. 192 Peter Robichaud, Dr. Andrew Larson and Dr. Heiko Langner. I would like to give special thanks 193 to Dr. Wakimoto, the chairman of my committee, for taking over as my advisor after the death of 194 Scott as well as for his encouragement throughout this process. I would like to thank Dr. Larson 195 and Dr. Langner for their patience and understanding after Scott’s passing. My deepest gratitude 196 goes out to Dr. Doerr and Dr. Robichaud for their indispensable guidance, support and insight in 197 the field of post-fire hydrology. I would also like to give acknowledgement to Dr. Michael 198 Hofmann for his never-ending optimism, countless insight and encouragement throughout the 199 years; it will never be forgotten. 200 I would like to thank Lubrecht Experimental Forest for the use of their facilities, in 201 particular Frank Maus who has supplied immense technical help over the years. I am very 202 grateful to the Philanthropic Educational Organization (PEO), especially the Missoula BT 203 chapter. Field data collection would not have been possible, or nearly as enjoyable, without the 204 aid of multiple field crews; Daniel Hatley, Jim Reilly, Keenan Storrar, Katie Jorgensen, Ian Hype 205 and Lance Glasgow. I would also like to thank Jim Reardon of the U.S.D.A. Forest Service vi 206 Rocky Mountain Research Station, whom has given me years of invaluable logistical support and 207 insightful conversation; Dr. Bill Granath and Jim Driver from Emtrix laboratories for teaching 208 me the wonders and frustrations of using an SEM, as well as allowing me access to their 209 machine; Swansea University for allowing me to accompany Scott for a month during his 210 sabbatical as well as access to a simultaneous thermal analyzer. I would like to thank the College 211 of Forestry for providing a friendly and caring place to work over the years, especially Shonna 212 Trowbridge, Catherine Redfern and Jim Adams for always answering my countless questions 213 with a smile.