fire regimes of the southern appalachian mountains

253 Pages·2012·6.12 MB·English

FIRE REGIMES OF THE SOUTHERN APPALACHIAN MOUNTAINS: TEMPORAL
AND SPATIAL VARIABILITY AND IMPLICATIONS FOR VEGETATION
DYNAMICS

A Dissertation
by
WILLIAM TREUTLEN FLATLEY

Submitted to the Office of Graduate Studies of
Texas A&M University
in partial fulfillment of the requirements for the degree of

DOCTOR OF PHILOSOPHY

Approved by:
Chair of Committee, Charles W. Lafon
Committee Members, David M. Cairns
Andrew C. Millington
X. Ben Wu
Head of Department, Vatche P. Tchakerian

December Choose an item.

Major Subject: Geography

Copyright 2012
ABSTRACT

Ecologists continue to debate the role of fire in forests of the southern
Appalachian Mountains. How does climate influence fire in these humid, temperate
forests? Did fire regimes change during the transition from Native American settlement
to Euro-American settlement? Are fire regime changes resulting in broad vegetation
changes in the forests of eastern North America? I used several approaches to address
these questions.
First, I used digitized fire perimeter maps from Great Smoky Mountains National
Park and Shenandoah National Park for 1930-2009 to characterize spatial and temporal
patterns of wildfire by aspect, elevation, and landform. Results demonstrate that fuel
moisture is a primary control, with fire occurring most frequently during dry years, in
dry regions, and at dry topographic positions. Climate also modifies topographic control,
with weaker topographic patterns under drier conditions.
Second, I used dendroecological methods to reconstruct historical fire frequency
in yellow pine (Pinus, subgenus Diploxylon Koehne) stands at three field sites in the
southern Appalachian Mountains. The fire history reconstructions extend from 1700 to
2009, with composite fire return intervals ranging from 2-4 years prior to the fire
protection period. The two longest reconstructions record frequent fire during periods of
Native American land use. Except for the recent fire protection period, temporal changes
in land use did not have a significant impact on fire frequency and there was little
discernible influence of climate on past fire occurrence.
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Third, I sampled vegetation composition in four different stand types along a
topographic moisture gradient, including mesic cove, sub-mesic white pine (Pinus
strobus L.)-hardwood, sub-xeric oak (Quercus L.), and xeric pine forests in an unlogged
watershed with a reconstructed fire history. Stand age structures demonstrate changes in
establishment following fire exclusion in xeric pine stands, sub-xeric oak stands, and
sub-mesic white pine-hardwood stands. Fire-tolerant yellow pines and oaks are being
replaced by shade-tolerant, fire sensitive species such as red maple (Acer rubrum L.) and
hemlock (Tsuga canadensis L. Carr.). Classification analysis and ordination of species
composition in different age classes suggest a trend of successional convergence in the
absence of fire with a shift from four to two forest communities.

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ACKNOWLEDGEMENTS

There are many people who deserve credit for the completion of this project.
First and foremost, I would like to thank my wife Jennifer for her support and
encouragement. She has never lost faith in me during this long process. I couldn’t have
done it without you. I would also like to thank my family for their continued support
during my educational journey. You have always encouraged and enabled me to pursue
my interests, no matter how far off the beaten path. Thank you and I love you all.
I would also like to thank my committee chair Dr. Charles Wilber Lafon, for
invaluable guidance in the art of field work, research, writing, teaching, and punnery. I
can only hope that I have absorbed a small portion of the knowledge that you impart on
a daily basis. I would also like to thank my committee members Dr. David Cairns, Dr.
Andrew Millington, and Dr. X. Ben Wu. In particular, I thank Dr. Cairns for guidance in
the analysis of the vegetation dynamics section. I also owe a debt of gratitude to Serena
Aldrich for blazing a trail as the original dendrochronology guru at Texas A&M
University. Your work made everything easier for me. Thank you for leading the way.
This project was made possible by the National Interagency Joint Fire Science
Project Grant # 06-3-1-05 issued to Dr. Charles Lafon, Dr. Henri Grissino-Mayer, and
Dr. Sally Horn. Additional funding during my graduate studies was generously provided
by the Texas A&M University Department of Geography, the Office of Graduate
Studies Phil Gramm Fellowship, and the Biogeography Specialty Group of the
Association of American Geographers.
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During this project I was aided by many professionals in the National Park
Service and U.S. Forest Service. In particular, I would like to thank Rob Klein and the
fire effects monitoring crew for help in the field and logistical guidance during field
work in GSMNP. A number of other people deserve thanks for providing guidance in
my search for fire history sites including, Beth Buchannan, Gary Kaufmann, Greg
Salansky, Steve Croy, guy in Nantahallah office. I would also like to thank House
Mountain State Natural Area, Great Smoky Mountains National Park, Pisgah National
Forest, Nantahala National Forests and Cherokee National Forest for granting
permission to collect samples. Finally, thank you to Great Smoky Mountains National
Park and Shenandoah National Park for providing me with the fire perimeter maps.
Finally, this project would not have been possible without an army of helpers in
the field and the laboratory. Thank you Dr. Charles Lafon, Dr. Henri Grissino-Mayer,
Lisa LaForest, Amanda Young, Jennifer Flatley, Ashley Pipkin, Sandra Metoyer,
Illiyana Dobreva, Ralph Baker, Brandon Wilcox, David Sitting Bear, Beth Munoz, Tyler
Pruett, Martina Antonia, Andrew Nidoh, Rob Klein, Ian Feathers, Grant Harley, Phillip
White, Nelson Lafon, and Griff the hound dog. The collection of 250 pine cross sections
and 1500 tree cores could not have been accomplished without all of your help. My days
in the field are my favorite memories from this process. Thank you for sharing them
with me.

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NOMENCLATURE

AF All Fires
AWF Area Wide Fire
AWI Area Wide Fire Interval
CART Classification and Regression Tree
CFI Composite Fire Interval
DBH Diameter at Breast Height
DEM Digital Elevation Model
EP Exclusion Period
FFI Filtered Fire Interval
FP Fire Period
GSMNP Great Smoky Mountains National Park
ISA Indicator Species Anlaysis
LEI Lower Exceedance Interval
MCFI Mean Composite Fire Interval
MF Major Fire
MFI Mean Fire Interval
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MRPP Multi-Response Permutation Procedure
NCDC National Climatic Data Center
NMS Non-metric Multidimensional Scaling
OS Origin to Scar
PDSI Palmer Drought Severity Index
PFI Point Fire Interval
PP Post-fire Period
RF Regional Fire
RFI Regional Fire Interval
SD Standard Deviation
SEA Superposed Epoch Analysis
SNP Shenandoah National Park
UEI Upper Exceedance Interval
WFI Weibull Median Fire Interval

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TABLE OF CONTENTS

Page
ABSTRACT ....................................................................................................................... ii
ACKNOWLEDGEMENTS .............................................................................................. iv
NOMENCLATURE ......................................................................................................... vi
TABLE OF CONTENTS ................................................................................................ viii
LIST OF FIGURES ........................................................................................................ xiii
LIST OF TABLES ........................................................................................................ xviii
INTRODUCTION ............................................................................................................. 1
Purpose of the Study ...................................................................................................... 6
Contemporary Landscape Patterns of Fire ................................................................. 6
Fire History ................................................................................................................. 9
Vegetation Dynamics ............................................................................................... 12

LITERATURE REVIEW ................................................................................................ 15
Fire Regimes in the Southern Appalachian Mountains ................................................ 15
Models of Fire and Vegetation Development in Eastern Forest .............................. 16
Pre-Euro-American Settlement Fire Regimes .......................................................... 17
Post Euro-American Settlement Fire Regimes ......................................................... 21
Fire Atlases ................................................................................................................... 23
Characterizing Fire Regimes .................................................................................... 23
Assessing Modern Changes in Fire Regimes ........................................................... 24
Identification of Controls on Fire Regimes .............................................................. 26
Combining Fire Atlases with Other Techniques ...................................................... 28
Issues of Bias within Fire Atlas Data ....................................................................... 29
Fire History Reconstructions ........................................................................................ 32
Methods for Using Fire Scars to Characterize Fire Regimes ................................... 32
Individual-Tree Fire Interval .................................................................................... 33
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The Mean Composite Fire Interval ........................................................................... 34
Origin-to-Scar Interval ............................................................................................. 36
Sample Size .............................................................................................................. 39
Targeted Sampling .................................................................................................... 40
Vegetation Dynamics ................................................................................................... 42
Community vs. Individualistic Concepts of Vegetation Association ....................... 42
Vegetation Disturbance ............................................................................................ 43
Characterizations of Disturbance .............................................................................. 44
Disturbance as regressive succession ....................................................................... 45
Disturbance mediated accelerated succession .......................................................... 45
Disturbance as a fundamental alteration in the successional sequence .................... 46
Disturbance and Vegetation Diversity ...................................................................... 47

METHODS* ..................................................................................................................... 49
Study Area .................................................................................................................... 49
Topography and Soils ............................................................................................... 49
Climate...................................................................................................................... 51
Vegetation ................................................................................................................. 52
Land Use History ......................................................................................................... 54
Native American ....................................................................................................... 54
Early Euro-American Settlement .............................................................................. 60
Period of Extractive Industry .................................................................................... 63
Era of Fire Protection and Suppression .................................................................... 63
Landscape Patters of Fire ............................................................................................. 65
Study Areas............................................................................................................... 65
Great Smoky Mountains National Park ................................................................ 65
Shenandoah National Park .................................................................................... 67
Spatial Data............................................................................................................... 67
Fire Perimeter Maps .............................................................................................. 67
Climate Data ......................................................................................................... 70
Topographic Data.................................................................................................. 70
Data Analysis ............................................................................................................ 71
Fire History .................................................................................................................. 75
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Study Sites ................................................................................................................ 75
House Mountain .................................................................................................... 75
Licklog Ridge........................................................................................................ 77
Linville Mountain ................................................................................................. 80
Field Methods ........................................................................................................... 82
Laboratory Methods ................................................................................................. 82
Data Analysis ............................................................................................................ 84
Fire Frequency ...................................................................................................... 84
Temporal Variations in Fire Activity .................................................................... 86
Fire-climate Relationships .................................................................................... 87
Vegetation Dynamics ................................................................................................... 89
Study Site .................................................................................................................. 89
Field Methods ........................................................................................................... 89
Laboratory Methods ................................................................................................. 90
Data Analysis ............................................................................................................ 91

RESULTS ........................................................................................................................ 95
Contemporary Landscape Patterns of Fire ................................................................... 95
Fire-climate Relationship ......................................................................................... 95
Fire-topography Relationships ............................................................................... 100
Climate-topography Interaction .............................................................................. 104
Fire History ................................................................................................................ 108
Fire Frequency ........................................................................................................ 109
Temporal Variations in Fire Activity ..................................................................... 124
Fire-climate Relationships ...................................................................................... 126
Vegetation Dynamics ................................................................................................. 131
Pine Stands ............................................................................................................. 131
Oak Stands .............................................................................................................. 131
White Pine-Hardwood Stands ................................................................................ 132
North Cove Stands .................................................................................................. 133
South Cove Stands .................................................................................................. 133
Classification of Forest Communities .................................................................... 143
Successional Change and Community Diversity .................................................... 147
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