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Genomics and Applied Biology, 2010, Vol.1, No.1
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Table 2 The mean residual fuel biomass and total carbon following shelterwood harvests in oak-hickory forests that reduced stocking
to 70% and 50% as compared to a control in Richland Furnace State Forest, Southern Ohio
Biomass (t/ha)
Carbon (t/ha)
Fuel type
Treatment
Mean
Standard deviation
Mean
Standard deviation
Herbaceous plants
50% stocking
70% stocking
Control
2.30a
0.23a
0.01a
7.36
0.27
0.04
0.79a
0.08a
<0.01a
2.51
0.09
0.01
Forest litter
50% stocking
70% stocking
Control
19.78a
21.36a
13.68a
19.30
13.61
2.47
9.76a
10.54a
6.75a
9.52
6.71
1.22
Woody plants
50% stocking
70% stocking
Control
0.41a
0.25a
0.29a
0.37
0.10
0.16
0.20a
0.12a
0.13a
0.18
0.05
0.08
Deadwood
50% stocking
70% stocking
Control
31.58a
20.14b
6.75c
14.91
7.27
2.86
15.79a
10.07b
3.38c
7.45
3.64
1.43
Total fuels
50% stocking
70% stocking
Control
54.07a
41.98a
20.73b
33.09
16.10
4.59
26.53a
20.81a
10.27b
15.40
7.99
2.28
Note: Lowercases mean followed by the same letter aren't significantly different between forest floor fuels (Duncan's MRT, p=0.05)
percentage of carbon for tree components. For many
the value is 50% (Nowak and Crane, 2002; Brack,
2002; Kimble et al., 2003, Makundi et al., 1995,
Dieter and Elsasser, 2002), with one at 45% (Nowak,
1993) and one at 46% (Patenaude et al., 2003). Canary
and other colleagues (2000) calculated the values for
fir and found a range of 48.1% to 54.6% with an
average of 51.2%. All of these values seem to be
consistent with the values determined from this study.
The carbon content value for herbaceous plants in this
study (34.12%) was significantly less than that of
woody plants and forest litter. Hughes and others
(1999) found the carbon content of grasses in humid
tropical climates to be 41%. If a standard value of
50% of dry plant weight had been used to estimate
carbon, it would have been overestimated by 46.5%.
While the herbaceous material made up only a small
fraction of the total fuel, this overestimation can be
quite significant in cases where herbaceous material
comprises a larger portion of the total fuel load.
2.2 Fuel Load and Carbon Emissions
The total fuel loading reported from this study for the
control (20.73 t/ha) was relatively close to the fuel-
loading factor of 19.5 t/ha used by EPA for deter-
mination of predicted prescribed fire emissions for
this region (Liu, 2004;
. epa.gov/
ttnchie1/net/v3announ cement.pdf). It likewise is close
to the mean fuel load value of 22.67 t/ha reported by
Woodall and his colleagues (2007) for oak-dominated
forest ecosystems in the eastern US. It is obvious that
harvesting has more than doubled the average fuel
load reported for these forest types.
Using emission factors reported by Battye and Battye
(2002; http://www.epa.gov/ttn/chief/ap42/ch13/related/
firerept.pdf), if all of this fuel is consumed one might
expect the carbon emissions reported in table 3 from a
wildfire, assuming average combustion efficiency and
fuel moisture. The potential is significantly greater in
the harvested areas compared to the control (Table 3).
It is doubtful that all of this fuel would be totally
consumed by a prescribed burn. However, because a
higher fuel load tonnage occurs in the forest litter (fine
fuels) in the harvested areas compared to the control, a
prescribed fire through harvested areas has a greater
potential to emit larger amounts of carbon. The actual
amount of carbon that is emitted will largely depend
upon how complete the combustion process is, and
whether it results in flaming or smoldering (Rowell