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The protective role of trees in soil conservation
Authors: C. O'LoughlinPublication: New Zealand Journal of Forestry, Volume N.Z.J.For. 2004, Issue N.Z.J.For. 49(4) 2005, pp 9-15, Jan 2005
Publisher: New Zealand Institute of Forestry
Abstract: The impacts on slope stability of Cyclone Bola in 1988 and the February storms in Wanganui-Manawatu in February 2004 provided strong evidence that treeless steepland is very vulnerable to mass wasting during large cyclonic storms whereas forested slopes are relatively resistant to failure. The evidence from numerous studies indicates it is the tree root systems which provide most of the additional resistance.
This paper briefly reviews the influence of trees on shallow landslides with most of the emphasis on radiata pine. The relatively rapid development of radiata pine root systems enables this species to provide good soil reinforcement after about 10 years of growth but within a few years after harvesting, most of the root reinforcement is lost. The various approaches that can be adopted to manage forests for soil protection, and identify where the most landslide-vulnerable slopes or parts of slopes are located, are outlined. Modern computer models, in combination with GIS, provide very useful predictions of instability.