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Long-term site productivity research - 30 plus years in the making

Authors: Peter Clinton, Loretta Garrett, Simeon Smaill
Publication: New Zealand Journal of Forestry, Volume N.Z.J.For. 2021, Issue N.Z.J.For. 66(2) 2021, pp 11-15, Aug 2021
Publisher: New Zealand Institute of Forestry

Abstract: Research that spans the full cycle of a stand of trees is rare. This paper summaries a series of recently published articles that provide detailed assessments of the impacts of intensive forest harvesting residue management over the life of several trials located around New Zealand. Key findings were that the impact of increasing harvest residue and forest floor removal on tree productivity was significant only on the poorer site where soil nitrogen pools were initially low, and the intensive residue removal further reduced nutrient pools. However, wood quality at the end of the rotation at the poorer site was not affected. The importance of the forest floor to nutrient storage and supply was demonstrated at the low nutrient sites. These findings demonstrate a need for site-specific management strategies if harvest residues are to be removed for use as feedstocks. The conclusions generated from this longterm research will be of benefit to the New Zealand forestry sector for many years to come. Future research needs are also described, with specific attention to the increasing proportion of planted forests that are entering their second or third or fourth rotation.