New Zealand Journal of Forestry (1985) 30(1): 70–86
©New Zealand Institute of Forestry
Soil resources of the Marlborough Sounds and implications for exotic production forestry. 2. Potential site disturbance and fine sediment production from various forest management practices.
M. D. Laffan , D. J. McQueen , G. J. Churchman and E. N. Joe
Regoliths (mantle of soil and weathered rock) on hilly and steep land in the Marlborough Sounds were classified as sources of fine sediment on the basis of texture, thickness and erodibility. The potential site disturbance by various forest management practices was assessed in relation to major slope classes. For steep slopes, ratings of potential effects on fine sediment production were then made in relation to ratings of sources of fine sediment for the main regolith types. Erosion of thick (1 m) regoliths occurring at <200 m alt. is likely to yield the most fine sediment. Ratings of potential site disturbance by forest management practices are also greater on these regoliths, particularly for such practices as creation of access tracks and firebreaks, scrub-raking, bulldozing, tractor skidding and cable skidding. To minimize effects from harvesting operations on hilly and steep land in the region it is recommended that alternative methods of log extraction such as skyline, balloon and helicopter logging be investigated.