University of Montana ScholarWorks at University of Montana Graduate Student Theses, Dissertations, & Professional Papers Graduate School 1995 6800-year vegetation and fire history in the Bitterroot Mountain Range Montana Anne Elizabeth Karsian The University of Montana Follow this and additional works at: https://scholarworks.umt.edu/etd Let us know how access to this document benefits ou.y Recommended Citation Karsian, Anne Elizabeth, "6800-year vegetation and fire history in the Bitterroot Mountain Range Montana" (1995). Graduate Student Theses, Dissertations, & Professional Papers. 6683. https://scholarworks.umt.edu/etd/6683 This Thesis 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]. Anne- K a r s j a n i Maureen and Mike MANSFIELD LIBRARY TheM University ontana of Permission is granted by tlie author to reproduce this material in its entirety, provided that tliis material is used for scholarly purposes and is properly cited in published works and repoits. * * Please check "Yes'' or “No “ and provide signature Yes, I grant permission ..\1 No, I do not grant permission ----- Author’s Signature Date; ' n 1 Any copying for commercial purposes or financial gain may be undertaken only with ^he author’s explicit consent. ■ Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. A 6800-YEAR VEGETATION AND FIRE HISTORY IN THE BITTERROOT MOUNTAIN RANGE, MONTANA By ANNE ELIZABETH KARSIAN Presented in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE UNIVERSHY OF MONTANA Department of Forestry 1995 Approved by: t' z o Chairperson 7 ^ ^ ^ /. A /' Deafi, Graduate School / Date ^ Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. UMI Number: EP37484 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. UMT Oi&MfWion Publishing UMI EP37484 Published by ProQuest LLC (2013). 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 P r o Q ^ s f ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 4 8 1 0 6 -1 3 4 6 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Karsian, Anne E., M.S., May 1995 Forestry A 6800-Year Vegetation and Fire History in the Bitterroot Mountain Range, M ontana. Chair: Kevin L. O'Hara The vegetation community near Marys Pond, Montana was analyzed through fossil pollen and microscopic charcoal in 46 samples from two combined sediment cores. Soon after the fall of Mazama ash (6850 B.F.; Bacon 1983) the vegetation community was briefly dominated by nonarboreal species. From about 6200-3500 yr B.P. vegetation of the surrounding area is represented by a Pinus (probably Pinus contorta) Pseudotsuga/Larix community suggesting a warmer climate with less effective moisture. While Pinus remains dominant, there was a suggested shift to mixed coniferous forest after 3500-2000 yr B.P. decreasing in the Pseudotsuga/Larix and increasing in Abies and Picea. This change in plant community may have indicated a cooling of temperatures and more moisture availability. By 2000 yr B.P., the forest appeared similar to the vegetation community presently surrounding Marys Pond characterized by a dominance of Pinus mixed with Abies, Larix and Picea. A similar shift in plant composition in response to temperature and moisture changes was observed at three other sites in western Montana where pollen analysis studies have been completed. Except for two samples, the microscopic charcoal analysis suggests a continuous series of variable intensity fires throughout the last 6800 years. Two distinct periods of high fire frequency and/or intensity centered around 3300 yr B.P. and 4000 yr B.P. are evident in the charcoal and pollen record. These may represent episodes of double or triple bum events. 11 Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS Page ABSTRACT........................................................................................................................ i i LIST OF FIGURES A N D TABLES..............................................................................v INTRODUCTION.............................................. ............................................................. l OBJECTIVES......................................................................................................................3 LITERATURE REVIEW Pollen and Fire History Studies .................................................................... 4 Use of ^Microscopic Charcoal for Interpreting Fire Histoiy ................ 6 STUDY AREA................................................................................................................... 8 METHODS Data Collection ................................................................................................... 11 Pollen and Data Analysis ....................... 14 RESULTS Sediments and Chronology ............................................................................ 17 Relative Frequency Diagram ......................................................................... 21 Pollen of Terrestrial Species ............................................................. 21 Pollen of Aquatic, Pond Edge and Fen Species .......................... 24 Spores ......................................................................................................... 25 Algae ...........................................................................................................25 PoUen/Charcoal Accumulation Rates .......................................................... 26 Ratios ..................................................................................................................... 27 Pollen Zones .......................................................................................................... 27 DISCUSSION Vegetation and Climate Post Mazama: 6800-6200 yr B.P. (Zone I) .................................... 29 Pseudostuga / Larix: 6200-3500 yr B.P. (Zone H) ........................ 30 Mixed Species: 3500-2000 yr B.P. (Zone III).................................. 31 Present-day: 2000 yr B.P.-Present (Zone IV) .............................. 34 Pines........................................................................................................................ 36 Bog Development ............................................................................................. 37 Fire History ........................................................................................................... 38 Charcoal Peaks ..................................................................................................... 43 iii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS (cont.) SUMMARY AND CONCLUSIONS........................................................................ 45 APPENDIX A .................................................................................................................. 48 REFERENCES CITED................................................................................................... 49 IV Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LIST OF HGURES Figure Page 1. Map showing location of Marj'^s Pond ..................................................... 9 2. Illustration of the sediment cores ............................................................. 12 3. Relatively percentage diagram of poUen spores and algae ................ 15 4. Depth of radiocarbon dates and calibrated radiocarbon dates .................................................................................... 19 5. Percent organic carbon from weight loss on ignition ........................ 20 6. Ratio of diploxylon to haploxylon pine pollen..................................... 22 7. Ratio of nonarboreal to arboreal pollen .................................................. 28 8. Ternary plot of Picea. Abies and Pseudotsuga / Larix ........................... 32 9. Relative percentage diagram of Picea. Abies and Pseudotsuga / Larix .................................................................................. 33 10. Ratio of Picea and Abies to Pseudotsuga / Larix ................................... 35 11. Ratio of charcoal fragments to total terrestrial pollen ....................... 39 12. Pollen and charcoal accumulation rates cm~2 year I ................. 4 0 13. Charcoal accumulation rate of three size classes cm"^ y e a r l ................................................................................................ 42 LIST OF TABLES Table Page 1. Vascular plants observed