Erosion is happening at 10-20 times faster than the rate topsoil can be formed by natural processes. [Pimentel 2006]

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Plantations and mono-culture re-growth on short term rotations (10 to 30 years) will result in continuous soil disturbance and nutrient loss, pauperising the soil and landscapes and destroying water catchments.

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This erosion together with the loss of organic matter which typically contains 3-4 times as much carbon as the vegetation above the ground together with continual burning of short term rotations will result in the pauperisation of the land and loss of productivity.

Following clearfelling and where the intercepting canopy is lost, the influence of the break up of soil particles by raindrops on the bare ground together with the steepness of the land and the degree of soil disturbance resulting from logging and road construction, can cause heavy soil loss and contamination of rivers and streams with silt and nutrients. The heavy sedimentation of streams is directly destroying the habitat of and threatening the survival of the Giant Freshwater Crayfish.

Nutrient loss from forest or land clearing can effect the ecology of inland waterways as excessive nitrogen and nutrient run-off often results in large algal blooms which are referred to as the eutrophication of waterways.

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The binding action of deep rooting trees and plants in forests promotes soil particle aggregation and stability which together with the leaf litter inhibit run-off and encourage the deep filtration of water. Once the land is cleared, destroying the root mass, the litter on the forest floor and organic content, the soil looses the ability to absorb or hold water, resulting in greater run-off erosion and more frequent flooding.

Typical sediment loads in run-off under natural conditions rarely exceed 10 p.p.m., while after forest clearing loads of over 70,000 p.p.m. have been recorded. Where logging rotations of 40-60 years take place there is a maximum reduction in water yield. "Who could love this River" (about siltation in the Tamar River) 1.3mb PDF brochure Courtesy : David Obendorf

PDF Brochure

Steep Slope Logging • Ref: P.E. Davies, M. Nelson The effects of steep slope logging on fine sediment infiltration into the beds of ephemeral and perennial streams of the Dazzler Range Tasmania.