Selection Silviculture Trials in North Island Native Forests: Impacts on the Residual Forest and their Implications for Sustainable Forest Managment

Authors: Mark C. Smale, A. E. Beveridge, John W. Herbert
Publication: New Zealand Journal of Forestry, Volume N.Z.J.For. 1998, Issue N.Z.J.For. 43(3) 1998, pp 19-30, Nov 1998
Publisher: New Zealand Institute of Forestry

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Abstract: Five management scale (24-45 ha) selection silviculture trials were established in central North Island podocarp forests between 1961 and 1979. In light of renewed interest in sustainable management, a variety of impacts on the residual forest over periods ranging from 3 to 22 years are reviewed. Despite the apparent suitability of podocarps for the group selection system, generally old canopy populations of rimu and matai with restricted age ranges and long rotations suggest that this is only attainable in the very long term. Tawa presents better prospects for selection management mimicking natural population processes.

Although harvest levels (9-55%) were well in excess of those approved under current legislation, the trials provide valuable insights into the likely ecological impacts of some current harvesting operations. Further documentation of longer term silvicultural and ecological outcomes will enable their full potential and relevance for current silvicultural practice to be realised

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