changes in fire regimes and the successional status of table mountain pine in the southern...
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Changes in Fire Regimes and the Successional Status of Table Mountain Pine in the Southern Appalachians
Henri D. Grissino-Mayer
Michael R. Armbrister
Laboratory of Tree-Ring Science
Department of Geography
University of Tennessee
Knoxville, Tennessee 37996
• Table Mountain pine endemic to Appalachians• Fire-dependent species: cone serotiny, site prep• Considerable human alterations to native communities• Primary among these is 20th century fire exclusion = new fire regime• Effects on this species are a major concern for management agencies
• Information needed on site-specific fire history• Retrospective study provides needed reference conditions
Problem Statement
• Evaluate current age structure of select TMP stands
• Identify and characterize historical fire regimes in these stands
• Combine this information to assess its current successional status
Objectives
Field Methods
1. Age structure analysis
Cored minimum 75 trees at 5 sites, 2 cores per tree
Aged seedlings and saplings via bud scars, branch nodes
2. Fire-scar analysis
Located suitable fire-scarred logs and snags
Collected small wedges from selected living trees
All sections collected via hand saws
Laboratory Methods
1. Age structure analysis
Mounted, sanded, dated all tree rings on all cores
Developed histograms that depicted the age structure of all 5 stands
2. Fire-scar analysis
Sanded, dated all tree rings on all sections
Dated all embedded fire scars to year of formation *
Developed graphs depicting fire occurrence over time
0
20
40
60
80
100
120
140
160
180
0 - 9
10 -
19
20 -
29
30 -
39
40 -
49
50 -
59
60 -
69
70 -
79
80 -
89
90 -
99
100 -
109
110 -
119
120 -
129
130 -
139
140 -
149
150 -
159
160 -
169
170 -
179
180 -
189
190 -
199
Age Classes
Fre
quen
cy
Stagnation!
Undated samples were very useful!
0
1
2
3
4
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
Interval
Fre
quency
Mean Fire Interval 8 yrsMedian Fire Interval 6Weibull Modal Interval (MOI) 5Weibull Median Interval (MEI) 7
Lower Exceedance Interval (LEI) 3Upper Exceedance Interval (UEI) 13Maximum Hazard Interval (MHI) 81
Preliminary statistics on fire history in TMP stands of the Great Smoky Mountains National Park
Major Conclusions
1. Living TMP crossdate very well = great potential.
2. Older dead and downed more difficult.
3. Age structure shows peaks in 60-69 and 70-79 classes.
4. Little to no regeneration is occurring in these stands.
5. Fire history information can be obtained even on undated samples.
6. Fires occurred ca. every 6-7 years in pre-park era.
7. Maximum Hazard Interval indicates conditions in these park stands are strongly conducive to burning.
Acknowledgements
Thank you JFSP!
GSMNP, NPS, Mike Jenkins
TVA, Charles Smart
Committee members: Ken Orvis, Sally Horn
Laboratory of Tree-Ring Science
Department of Geography, University of Tennessee
Field and lab help from:
Daniel Lewis, David Mann, Jake Cseke, Beth Atchley, Damian Kolbay, Bill Dennis, Brian Reed