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Genomics and Applied Biology, 2010, Vol.1, No.1
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left more coarse woody debris. The 70% treatment
contained a large amount of small branches <5 cm
diameter in the logging residue as indicated by the
higher forest litter component.
Herbaceous material contributed very little to the fuel
loading in all treatments and the control (table 2). Still,
a trend was indicated that a more open canopy plus
greater disturbance allowed more herbaceous plants to
develop. The greatest amount was found in the 50%
treatment, followed by the 70% treatment and the
control, respectively. Small woody plants likewise
contributed very little to the overall fuel component
one year after harvest. No trends were revealed relative to
harvest intensity or compared to the control.
Both harvesting treatments created significantly more
total fuel than what currently existed in the control (no
harvesting). The majority of the fuel was contained in
the forest litter and deadwood material. The
contribution of deadwood material to the total fuel
load decreased as harvesting intensity decreased.
Deadwood accounted for 58.4%, 48.0% and 32.6% for
the 50% treatment, 70% treatment, and control,
respectively. This trend was reversed for forest litter,
which represented 36.6%, 50.9% and 67.0% of the
total fuel load for the 50% treatment, 70% treatment
and the control, respectively.
In terms of tonnage, the less intensive harvesting
treatment produced 8% more litter material but 36%
less deadwood material than the more intensive
harvest treatment (Table 2). This may be a reflection
of the type of harvesting system used to implement the
treatments. A mechanical cut-to-length system was
employed, using a knuckle-boom feller-buncher to
harvest the trees and a forwarding machine to extract
the wood. The less intensive harvest treatment would
make maneuverability more difficult and utilization of
topwood material more difficult. Accordingly, more
small branch material would be left behind as a result
of lower utilization and more frequent branch
breakage would occur while maneuvering through a
more dense forest. Because of lower volumes being
extracted from the less intensive harvest, it becomes
more imperative to utilize more of the larger material;
Thus less of the larger deadwood material would be
left behind.
Jenkins and his colleagues (2004) found more residual
coarse woody debris following less intensive harvests
(group selection) than in more intensive (clear cuts).
Their explanation for this observation was the
different market forces related to each harvesting
systems. Smaller openings created by group selection
may not make it economically feasible to utilize as
much topwood as it might in a clearcut system due to
comparatively low volumes produced in a dispersed
harvesting system.
The carbon stored in the fuels follows the similar
trends as the fuel loading. Significantly more carbon is
stored in fuels after harvests compared to the control,
averaging 98%~118% more stored carbon (Table 2).
The majority of the stored carbon (65.7%) in the
unharvested control is contained in the forest litter,
whereas the majority of stored carbon in the 50%
treatment (59.5%) is contained in the residual
deadwood material. The stored carbon in the 70%
treatment is evenly distributed in both the forest litter
(50.6%) and the deadwood material (48.4%).
Where the carbon is stored is critical when considering
fire events. Whether the fire is wild or prescribed, the
majority of the fuels consumed would be the forest
litter material. A prescribed burn would consume some
of the smaller deadwood material, but a wildfire would
more than likely consume a larger fraction of this
material. Accordingly, one would expect larger carbon
emissions from a wildfire compared to a prescribed burn.
2 Discussion
2.1 Percent Carbon
The percent carbon by weight values are consistent
with that found by Nicodemus and Williams (2004)
for woody components of hardwoods in Ohio
(47.52%), and by Koch (1989), where the average
carbon content for tree species in the United States
was 52.1% for softwoods and 49.1% for hardwoods.
Hughes and his colleagues (1999) found percent
carbon values for litter and small woody stems
(seedlings) to be 45% and 43%, respectively. This
compares to 49.34% for litter and 48.09% for small
woody stems found in this study.
Many of the studies in the literature use one standard