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. While deforestation rates have slowed since 2004, forest loss is expected to continue for the foreseeable future. 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.
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