Basic HTML Version
Genomics and Applied Biology, 2010, Vol.1, No.1
http://gab.sophiapublisher.com
- 7 -
diameter). The higher harvest intensity (50%
treatment) created significantly more deadwood
material than the lower intensity (70%), with both
treatments having significantly more deadwood than
the control. Increase in harvest intensity leads to
higher residual fuel loading. The amount of carbon
stored within these fuels follows the same trends.
Forest managers need to give consideration to the
subsequent fuel loading that result from various
harvest intensities, which could create increased risks
of wildfire through these stands. Harvesting increased
the amount of 1 to 10 hours fuels on the forest floor,
which are the fuels most likely to influence fire
behavior and determine its sustainability. Harvesting
also increased the amount of 100 hours and 1 000
hours fuels, but to a lesser extent. The greatest
increase in the 1 000 hours fuel category occurred
with the most intensive harvest.
Wildfire is more likely when weather conditions are
hot and dry, particularly over extended periods, which
make more fuel available. Accordingly, wildfire tends
to display more extreme fire behavior and consume
more fuel. In the case of this study wildfire could have
the potential of releasing 70~90 t/ha of carbon
emissions into the atmosphere in post-harvest stands
compared to 35 t/ha in unharvested stands.
Prescribed fire on the other hand is often implemented
under conditions less favorable for wildfire, but
conducive enough to carry fire. Accordingly, only the
1 to 10 hours surface fuels that have the greatest
influence on fire behavior are typically consumed.
Normally, emissions from prescribed fire are less than
what is emitted from wildfire (Liu, 2004). In the case
of this study, if prescribed fire consumed 1 hour and
10 hours fuels, the estimated carbon emissions from
harvested areas would be 39~42 t/ha, compared to 24
t/ha from unharvested areas. The use of prescribed fire
can reduce the wildfire risks and the associated carbon
emissions from these events. Accordingly, it may be
worthwhile to account for the reduction in carbon
emissions obtained when prescribed burns are
implemented as a fuel reduction strategy (Narayan et
al., 2007) in carbon offset projects. In the case of
harvested stands this could mean a total carbon
emission reduction of 44%~55%, whereas in
unharvested stands the emissions could be reduced
32%.
3 Materials and Methods
3.1 Field Methods
This study was part of a larger study to examine the
effects of combined shelterwood harvests and
prescribed fire on establishment of oak regeneration in
the Richland Furnace State Forest. Shelterwood
harvests of two different intensities were
implemented-reduction of the forest to 70% stocking
(less intensive) and reduction to 50% stocking (more
intensive). The percent stocking (forest density) was
determined by using stocking charts for upland
hardwoods (Gingrich, 1967). A mechanical cut-to-
length harvesting system was used to harvest stands.
Three to five years following these harvests a
prescribed burn will be introduced once the oak
regeneration and its competitors have established. One
set of 70% and 50% stocking treatments will receive a
spring burn, and another set a fall burn. These
treatments will be compared to a control, in which no
harvesting or bur- ning treatments will occur. The data
collection for this study occurred one growing season
following harvest so no burning had taken place.
Richland Furnace State Forest (44.769°N, 117.168°W)
lies within the unglaciated Allegheny Plateau Region,
and is extensively dissected by watershed drains that
exhibit undulating and rough topography. Elevation
within the region ranges from the lowest point of 180
m to the highest point of 320 m above sea level. The
total annual precipitation is 104 cm, with over half of
this precipitation occurring of April through
September. The forest was dominated by oak and
other mixed hardwood species (Table 6). The basal
area averaged 24.3 m2/ha with 326 trees/ha, where
oak and hickory accounted for 84 percent of the basal
area. While the residual stand targets for the
shelterwood harvest intensities were 70% and 50%
stocking, actual residual stocking was 65% and 43%,
respectively, based on plot data (Table 7).
The fuel data collected for this study utilized the
sampling design of the larger study. Each treatment
and control was 10-ha in size, and each contained
eight 0.08-ha circular sample plots. The center of each
of these plots served as the sample point for this study.