Logging companies also justify large clear-cuts on the grounds that
it emulates the disturbances that historically have been caused by
forest fires. They suggest that clear-cuts removes tree canopies, thus
allowing other tree species to get the sunlight they need to flourish.
However scientific evidence shows that the benefits associated with
natural fires are not present in clear-cuts. For example, many trees
release seeds when they are exposed to high temperatures – this ensures
regeneration of the forest after the fire is over. In addition, when
leaves and woody debris burn, extra nutrients are produced which is
absorbed into the soil. This further encourages new growth.
Clear-cutting removes seed sources as well as natural debris that would
be left over from a fire. Clear-cutting also requires the construction
of roads, which fragments habitat and increases the risk of invasive
species.Clear-cutting may be profitable for logging companies, but it
has enormous ecological and social costs.
According to the Oregon Forest Resources Institute (OFRI), clear cutting
is the process by which all the trees in a given section of a forest
are logged at once, with only a small number of trees left standing.
While OFRI indicates that the trees in question are replanted after two
years, the replanting does not undo all the damage that clearcutting can
cause.
Patches of clear-cut mountain (stock image). Clear-cutting loosens up
carbon stored in forest soils, increasing the chances it will return to
the atmosphere as carbon dioxide and contribute to climate change, a
Dartmouth College study shows.
Effects of clear-cutting on the dissolved fluxes of organic C (DOC),
organic N (DON), NO3− and NH4+ through surface soil horizons were
studied in a Norway spruce dominated mixed boreal forest in eastern
Finland. Bulk deposition, total throughfall and soil water from below
the organic (including understorey vegetation and, after clear-cutting,
also logging residues), eluvial and illuvial horizons were sampled
weekly from 1993 to 1999. Clear-cutting was carried out in September
1996. The removal of the tree canopy decreased the deposition of DOC and
DON to the forest floor and increased that of NH4+ and NO3− but did not
affect the deposition of total N (DTN, <3 kg ha−1 a−1). The leaching
of DOC and DON from the organic horizon increased over twofold after
clear-cutting (fluxes were on an average 168 kg C and 3.3 kg N ha−1
a−1), but the increased outputs were effectively retained in the surface
mineral soil horizons. Inorganic N deposition was mainly retained by
the logging residues and organic horizon indicating microbial
immobilization. Increased NO3− formation reflected as elevated
concentrations in the percolate from below the mineral soil horizons
were observed especially in the third year after clear-cutting. However,
the changes were small and the increased leaching of DTN from below the
illuvial horizon remained small (<0.4 kg ha−1 a−1) and mainly DON.
Effects of clear-cutting on the transport of C and N to surface waters
will probably be negligible.
Salmon runs, fisheries, tourism and recreation support $2 billion in
revenues and more than one million visitors each year. However, due to
scorched-earth logging practices that utilized a technique of clear
cutting full forest areas, Tongass has lost at least half of its old
growth forest since the 1950s. Logging companies exploited cheap
undervalued heavily-subsidized lumber to ravage Tongass’s old growth
trees.
The world’s rain forests could completely vanish in a hundred years at
the current rate of deforestation. Between June 2000 and June 2008 more
than 150 000 square kilometers of rain forest were cleared in the
Brazilian Amazon. Huge areas of forest have already been lost. For
example, only eight to fourteen percent of the Atlantic Forest in South
America now remains.[22][23] While deforestation rates have slowed since
2004, forest loss is expected to continue for the foreseeable
future.[24] Farmers slash and burn large parcels of forest every year to
create grazing and crop lands, but the forest’s nutrient-poor soil
often renders the land ill-suited for agriculture, and within a year or
two, the farmers move on.[25]
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