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Summary of 2012 Fire Effects Monitoring for the
Southern Blue Ridge Fire Learning Network1
Peter Bates2
December 21, 2012
Introduction: Forest Stewards, Inc. entered into a contract with The Nature Conservancy to
monitor fire effects on prescribed burn demonstration sites for the Southern Blue Ridge Fire
Learning Network (SBR FLN). We completed the following tasks as part of that contract:
1. During the summer of 2012 we collected post-burn data for 4 sites (Flat Branch, Lake James,
Needmore, and Steeltrap Knob).
2. Began initial data summarization and presented the results in a poster and the 2012 National
Convention of the Society of American Foresters Convention in Spokane, WA.
3. Presented a webinar on November 29, 2012 describing an ecozone approach to summarizing
results. That presentation serves as an outline for a proposed journal article.
Field Data Collection Methods: All data were collected using 1/10 acre permanent plots.
During this data collection effort, 30 plots were measured within the burn unit for Cold Mountain
#1, 10 plots were measured within the burn unit for Cold Mountain #2, 18 plots were measured
in the area around the Cold Mountain sites, and these will serve as control plots for both Cold
Mountain #1 and #2. An additional 20 plots were established at Woods Gap. Fifteen were
located within the proposed burn unit and 5 were located in a control area. The data collected at
each plot are described below:
Data Type Methods and Attributes
Plot location UTM coordinates of plot center collected by averaging at least 200
GPS positions
Aspect Azimuth with a compass
Landform NCVS categories: ridgetop, open slope, spur ridge, gap, knob,
plunging cove, valley bottom, bench
Elevation Determined from DEM/GIS based on UTM coordinates
Slope Nearest percent with a clinometer
Slope position Classified as either upper, mid, lower
Slope shape Classified as either flat, concave, convex
Photos 1 repeatable photo point established per plot
Fuels
Litter and duff depths
Count of 1-hr, 10-hr, 100-hr, and 1000-hr fuels (woody ≥ 3”
diameter at intersection) by diameter
Data collected and summarized using protocols developed by
Southern Research Station, Clemson office.
Trees (data collected for
all trees > 2 inches DBH
within a 1/10th
acre fixed
radius plot)
Species
DBH
Crown class: Dominant, Codominant, Intermediate, or Overtopped
Mortality class based on percent live crown
1 Final report prepared by Forest Stewards, Inc and presented to The Nature Conservancy in reference to contract
number FIRE_FSI_052212-001 2 Department of Geosciences and Natural Resources, Western Carolina University (bates@email.wcu.edu)
Regeneration (data will be
collected for all tree
species > 1 ft tall and < 2
inches DBH within a 1/50th
acre fixed radius plot)
Stem count by species
Stem height:
1 to 2.99 ft
3 to 4.49 ft
> 4.5 ft
Stem origin:
Sprout/sucker
Single stem
Sprout clumps will be treated as a single plant with height of tallest
stem measured
Understory (data will be
collected for non-tree
species in the same 1/50th
acre plot as Advanced
Regeneration data)
% Cover in 5% increments plus 0-1, 1-2, 2-3, 3-4, 4-5% for the
following life forms:
bare ground
boulder
moss/lichen
grass/grass-like
ferns
other herbs/forbs
vines
deciduous shrubs
evergreen shrubs (includes mountain laurel and rhododendron)
mountain laurel
rhododendron
Overview of SBR FLN demonstration burn units: When combining the this year’s efforts with
those of the past, Forest Stewards, Inc, and WCU have been involved in data collection and
monitoring on a total of 13 SBR FLN burn units (Fig. 1). At least 1 controlled burn has been
completed on 10 of the 13 burn units, and the remaining 3 are prepped and scheduled to be
burned as soon as conditions allow. Other characteristics of the burn units include (Table 1):
8 of the units target Oak Hickory community types and 5 units target Yellow Pine
community types
9 units have been burned once, 1 has been burned twice, and 3 have yet to be burned
7 of the units burned to date have been spring burns and 3 of the units burned to date have
been fall burns.
Figure 1. Locations of SBR FLN burn units being monitored by Forest Stewards, Inc and Western
Carolina University as of December, 2012.
Table 1. Overview of SBR FLN demonstration burn units. Cells in green represent periods of data
collection. HERB indicates a satellite study where non-mast species < 6 inches DBH were treated with
herbicide. Cells in red represent years of prescribed burns. All burns are spring burns unless another
season is indicated.
Completed
Not
completed
Burn unit Target community(ies) 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015
Flat Branch Shortleaf pine-
oak
Yellow Creek Shortleaf pine-
oak Pine-oak-heath
Needmore Shortleaf pine-
oak Pine-oak-heath
Steeltrap Knob High elevation
red oak
Dry mesic oak-
hickory FALL
Tugalo Village Shortleaf pine-
oak
Silver Run Dry mesic oak-
hickory
Cold Mountain #1 High elevation
red oak
Dry mesic oak-
hickory HERB
Cold Mountain #2 High elevation
red oak
Dry mesic oak-
hickory
Davis Creek High elevation
red oak
Dry mesic oak-
hickory
Lake James Shortleaf pine-
oak
Woods Gap Dry mesic oak-
hickory
Bluff Mountain High elevation
red oak
FALL
3 top Mountain High elevation
red oak
FALL
The following figures show pre and post burn results for overstory basal by species and
advanced regeneration by species for each of the 4 burn units sampled this summer (Flat Branch,
Lake James, Needmore, and Steeltrap Knob). In all cases, postburn results represent conditions
in the 2nd
growing season after the fire.
0
10
20
30
40
50
60 B
asal
are
a (f
t^2
/acr
e)
Preburn Postburn
Overstory basal area for the Flat Branch burn unit preburn and during the second growing
season following the burn
Total preburn BA: 152.1 ft2/acre Total postburn BA: 153.2 ft2/acre
0
100
200
300
400
500
600
Den
sity
(st
ems/
acre
)
Preburn Postburn
Advanced regeneration for the Flat Branch burn unit preburn and during the second growing
season following the burn
Total preburn density: 1860 stems/acre Total postburn density: 990 stems/acre
0
5
10
15
20
25
30
35
40
Bas
al A
rea
(ft^
2/a
cre
)
Preburn Postburn
Overstory basal area for the Lake James burn unit preburn and during the second growing season
following the burn
Total preburn BA: 92.3 ft2/acre Total postburn BA: 92.1 ft2/acre
0
20
40
60
80
100
120
140
160
180
200
De
nsi
ty (
ste
ms/
acre
)
Preburn Postburn
Advanced regeneration for the Lake James burn unit preburn and during the second growing season
following the burn
Total preburn density: 547 stems/acre Total postburn density: 413 stems/acre
0
10
20
30
40
50
60 B
asal
are
a (f
t^2
/acr
e)
Preburn Postburn
Overstory basal area for the Needmore burn unit preburn and during the second growing season
following the burn
Total preburn BA: 152.1 ft2/acre Total postburn BA: 153.2 ft2/acre
0
100
200
300
400
500
600
700
Den
sity
(st
ems/
acre
)
Preburn Postburn
Advanced regeneration for the Needmore burn unit preburn and during the second growing season
following the burn
Total preburn density: 2020 stems/acre Total postburn density: 2120 stems/acre
0
5
10
15
20
25
30
35
40
45
50 B
asal
are
a (f
t^2
/acr
e)
Preburn Postburn
Overstory basal area for the Steeltrap Knob burn unit preburn and during the second growing
season following the burn
Total preburn BA: 125.7 ft2/acre Total postburn BA: 119.9 ft2/acre
0
50
100
150
200
250
Den
sity
(st
ems/
acre
)
Preburn Postburn
Advanced regeneration for the Steeltrap Knob burn unit preburn and during the second
growing season following the burn
Total preburn density: 1247 stems/acre Total postburn density: 917 stems/acre
Summarizing results by ecological zone: We propose that it may be most appropriate to analyze
and present results by ecological zone rather than by individual burn units. There is considerable
variability within each burn unit, which makes interpretation of the results difficult.
Summarizing the results by ecozone will allow us to work around some of this variability, and
perhaps more importantly, would allow us to extrapolate our results to similar ecozones across
the landscape. The latter would provide resource managers with a better tool to assess how best
to use fire in landscape-scale restoration efforts.
For our analyses, we used ecozones developed by Steve Simon, which have been the
principal ecological units used by the SBR FLN. Table 2 shows the distribution of those units
within our burn units.
Our plots were primarily located in 6 of 7 ecozones that were most common in our burn units.
We had very few plots in areas classified as Acidic Coves, which is consistent with the fact that
that we did not target coves during plot location. We have pre and postburn data for 105 plots
located within the 6 ecozones, and we used those plots to evaluate fire effects by ecozone (Table
3).
Table 2. Area (acres) of each Simon Ecozone type in each burn unit
Burn Unit
Ecozone
Acidic
Cove
Dry
Mesic
Oak HERO
Montane
Oak
Hickory
Pine-
Oak
Heath
Rich
Cove
Shortleaf
Pine Oak
Total unit
area (ac)
FlatBranch 228 180
116
755 1,279
YellowCreek 148 190
102 101 183 5 728
Needmore 78 5
14 2
105 205
Steeltrap 166 151 120 385 1 12
835
Tugalo Vil 91 892
127 1 4 1,311 2,426
SilverRun 73 334
56
0
463
ColdMtn1 0
0 59 1 11
70
ColdMtn2 0
4 49 1 38
92
DavisCrk 174 55 29 471 198 118
1,045
LakeJames 516 895
23 180
339 1,954
WoodsGap 185 759
448 208 31 1 1,632
Bluff Mtn
57 16
73
3 Top Mtn 1
40 52
1
94
Total (ac) 1,660 3,462 250 1,919 693 398 2,515 10,897
Table 3. Number of plots in each ecozone
Ecozone # Plots
Dry Mesic Oak Hickory 16
HERO 7
Montane Oak Hickory 33
Pine Oak Heath 5
Rich Cove 7
Yellow Pine Oak 31
Grand Total 105
0
1
2
3
4
5
6
7
Pine Oak Heath
Dry Mesic Oak Hickory
Yellow Pine Oak
Montane Oak Hickory
Rich Cove HERO
Arb
ore
al
Mo
istu
re I
nd
ex
Ecozone characterzation: We developed an Arborial Moisture Index (AMI) based on the
species composition of the overstory trees (modeled after McNab 2003). Each tree was assigned
a moisture index value ranging from 1 (xeric) to 10 (mesic) based on conditions where that
species is typically found in the southern Appalachians. AMI is calculated for each plot based
on the average of those values for each overstory tree in the plot.
AMI varied significantly with ecozone (F=55, P < 0.001), and the values followed a logical
pattern. This to supports that the ecozones were identifying unique ecological units (Fig. 2).
Figure 2
0
20
40
60
80
100
120
140
160
Dry Mesic Oak Hickory
Yellow Pine Oak
Rich Cove HERO Montane Oak Hickory
Pine Oak Heath
Number killed Percent remaining
0
10
20
30
40
50
60
70
80
HERO Dry Mesic Oak Hickory
Rich Cove Yellow Pine Oak
Montane Oak Hickory
Pine Oak Heath
BA
red
uct
ion
(%
)
Fire effects on overstory mortality: For many of our target communities, restoration will require
some reduction in the forest overstory. We examined total mortality of stems between 2 and 6 in
DBH to evaluate whether changes in stand structure were occurring after 1 burn, and we
summarized the results by ecozone. Ecozones varied significantly in both the number of stems
per acre killed (F=110, P < 0.001) and percent of stems remaining (F=520, P < 0.001) as
measured in the second growing season following a single burn (Fig. 3):
We also found significant differences by ecozone in the percent in basal area reduction in the
intermediate and overtopped crown classes (F=443, P < 0.001) (Fig. 4).
Fire effects on regeneration: We enter into the following discussion with the caveat that we feel
it is premature to begin rigorously assessing fire effects on regeneration. We have only collected
postburn fire results for 7 of our 13 burn units. In addition, except for 1 unit, all of our results
are for a single burn, the effects of which are often considered uninformative. However, we do
present the following observations to demonstrate some initial trends and observations.
Figure 3
Figure 4
0
500
1000
1500
2000
2500
3000
3500
4000
4500
Dry Mesic Oak Hickory
HERO Montane Oak Hickory
Pine Oak Heath
Rich Cove Yellow Pine Oak
De
nsi
ty (
ste
ms/
acre
)
Preburn Postburn
Regeneration density: For most ecozones, there seemed to be a slight (though likely
insignificant) decrease in the density of advanced regeneration in the second growing season
following the burn. The one exception was in the Pine Oak Heath ecozone where regeneration
density did increase (Fig. 5). In is interesting that this is also the ecozone that experienced the
greatest reduction in basal area of trees in intermediate and overtopped crown classes (Fig. 4)
suggesting that opening these stands up more might have stimulated a regeneration response.
Figure 5
0
200
400
600
800
1000
1200
1400
1600
1800
Dry Mesic Oak Hickory HERO Montane Oak Hickory Pine Oak Heath Rich Cove Yellow Pine Oak
Den
sity
(st
ems/
acre
) Preburn Postburn
0
500
1000
1500
2000
2500
3000
3500
Dry Mesic Oak Hickory
HERO Montane Oak Hickory
Pine Oak Heath Rich Cove Yellow Pine Oak
Den
sity
(st
ems/
acre
)
Regeneration by species groups: In this analysis we looked at whether different groups of
species responded differently to fire. Regenerating species were grouped into 3 categories, Oak
Hickory (all oaks and hickories), Yellow Pine (all yellow pines), and Mesophytic (all other
species). We have observed very little Yellow Pine regeneration (either pre or postburn), so we
only present the results for Oak Hickory and Mesophytic (Fig. 6). Again, while no statistical
analyses were done, there is no strong indivation that either species group responded differently
than the other in any of the ecozones. In all ecozones (with the exception of Pine Oak Heath),
there may have been a slight decrease in regeneration density, but the decrease was similar for
both species groups. Similarly, in the Pine Oak Heath ecozone, where there appeared to be an
increase in regeneration density following a single burn, both Oak Hickory and Mesophytic
species responded positively.
Figure 6
Oak Hickory
Mesphytic
0
100
200
300
400
500
600
700
800
900
1000
De
nsi
ty (
ste
ms/
ac)
Preburn Postburn
Regeneration of individual species: We pooled the results for individual species across all
ecozones to look for trends (Fig. 7). Again, we urge caution when interpreting these data;
however the results do seem to support several observations that were made in the field. First,
some species appeared to be stimulated by a single burn in some locations. These included
sassafras, blackgum, and black locust, all species that sucker from the roots. Conversely, white
pine regeneration appeared to be drastically reduced by a single burn. We should be able to
refine these results further as our monitoring continues and we gather results from additional
sites.
Figure 7
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
90.0
100.0
Preburn 1GS post 1st Burn
2GS post 1st Burn
3GS post 1st Burn
1GS post 2nd .Burn
2GS post 2nd .Burn
3GS post 2nd .Burn
Pe
rce
nt
of
cro
wn
wit
h a
corn
s Unburned Burned
Fire effects on hard mast production (Cold Mt #1): At Cold Mt #1, the NC Wildlife
Resources Commission has been collecting hard mast data from about 50 oaks and hickories
located inside the burn unit and from another 50 trees outside the burn unit. Mast production
was estimated based on the percent of the crown with acorns or nuts as determined in mid to late
summer. Data collection began in 2006 prior to the initial burn and has continued each summer
through 2012. This unit has been burned twice – once during the spring of 2007 and again
during the spring of 2010.
It appeared that prescribed burning generally stimulated hard mast production. The
effects appeared greatest in the year of a burn, and then tended to taper off in subsequent years.
The pattern was similar after each of the 2 burns.
White oaks demonstrated the greatest response, with trees inside the burn unit showing
significantly greater acorn production in the summer immediately after a spring burn (Fig. 8,
Table 3).
Table 4. T-test results comparing unburned versus burned mast production for each year for white oaks
Percent crown with acorns
Unburned Burned
Year Period mean var sd mean var sd P-value
2006 Preburn 32.9 438.4 20.9 37.2 303.2 17.4 0.560896
2007 1GS post 1st Burn 16.4 175.5 13.2 45.9 764.1 27.6 0.003022
2008 2GS post 1st Burn 0.4 2.1 1.4 3.6 13.2 3.6 0.00952
2009 3GS post 1st Burn 0.4 2.1 1.4 0.7 3.1 1.8 0.695082
2010 1GS post 2nd .Burn 26.7 1100.0 33.2 56.3 1037.4 32.2 0.041853
2011 2GS post 2nd .Burn 0.0 0.0 0.0 0.0 0.0 0.0 NA
2012 3GS post 2nd .Burn 1.7 6.3 2.5 2.3 10.2 3.2 0.599126
Figure 8. White Oaks
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
Preburn 1GS post 1st Burn
2GS post 1st Burn
3GS post 1st Burn
1GS post 2nd .Burn
2GS post 2nd .Burn
3GS post 2nd .Burn
Pe
rce
nt
of
cro
wn
wit
h a
corn
s
Unburned Burned
Similar patterns were also observed for Hickories (Fig. 9, Table 5) and Red Oaks (Fig. 10, Table
6)
Table 5. T-test results comparing unburned versus burned mast production for each year for hickories
Percent crown with acorns
Unburned Burned
Year Period mean var sd mean var sd P-value
2006 Preburn 35.0 508.3 22.5 42.5 800.0 28.3 0.583816
2007 1GS post 1st Burn 2.1 15.5 3.9 11.3 98.2 9.9 0.040778
2008 2GS post 1st Burn 27.9 265.5 16.3 35.0 535.7 23.1 0.507957
2009 3GS post 1st Burn 8.6 31.0 5.6 9.4 124.6 11.2 0.865977
2010 1GS post 2nd .Burn 16.7 576.7 24.0 28.1 721.0 26.9 0.425289
2011 2GS post 2nd .Burn 1.7 6.7 2.6 7.5 57.1 7.6 0.097458
2012 3GS post 2nd .Burn 5.0 10.0 3.2 10.0 235.7 15.4 0.451725
Figure 9. Hickories
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
80.0
Preburn 1GS post 1st Burn
2GS post 1st Burn
3GS post 1st Burn
1GS post 2nd .Burn
2GS post 2nd .Burn
3GS post 2nd .Burn
Pe
rce
nt
of
cro
wn
wit
h a
corn
s
Unburned Burned
Table 6. T-test results comparing unburned versus burned mast production for each year for red oaks
Percent crown with acorns
Unburned Burned
Year Period mean var sd mean var sd P-value
2006 Preburn 2.7 8.1 2.8 1.6 7.2 2.7 0.09474
2007 1GS post 1st Burn 0.6 2.9 1.7 8.7 241.6 15.5 0.005638
2008 2GS post 1st Burn 48.1 617.8 24.9 33.4 552.0 23.5 0.023743
2009 3GS post 1st Burn 5.2 47.5 6.9 8.0 146.7 12.1 0.275798
2010 1GS post 2nd .Burn 10.4 421.8 20.5 25.4 629.3 25.1 0.025453
2011 2GS post 2nd .Burn 1.8 10.2 3.2 3.8 42.6 6.5 0.163946
2012 3GS post 2nd .Burn 29.1 1080.1 32.9 40.6 652.8 25.5 0.184188
Figure 10. Red Oaks
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