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Tending Pinus radiata for Optimum Timber-garde Recovery
Authors: R. Fenton, A.K. FamiltonPublication: New Zealand Journal of Forestry, Volume N.Z.J.For. 1959, Issue N.Z.J.For. 8(3) 1961, pp 415-439, Nov 1961
Publisher: New Zealand Institute of Forestry
Abstract: Logs of 41-year-old Pinus radiata (D. Don) trees were sawn to one-inch timber in a frame-saw mill, and subsequent recovery of the higher board grades was poor. The original stand had been low and high pruned, and thinned three times, but this tending had been too light in intensity, and had been timed too late to be effective in improving grade recoveries.
The major defects of the timber were bark encasement of the knots, cone-stem holes, and pith associated with low-density corewood and spike knots.
Final-crop trees should ideally be straight-stemmed, with branches of small diameter set at wide angles to the trunk; should be relatively free of stem cones, and without marked nodal swellings, and should have a reasonable degree of vigour.
In stands of 59-year old trees studied, natural pruning was negligible, and stem cones were particularly persistent.
Contemporary tending schedules in New Zealand now prescribe very heavy thinning combined with pruning to 32 ft or higher. A conservative projected grade yield from final-crop trees produced according to the 1960 tending schedule for Southland Conservancy indicates that at least 35 percent of the timber will be clear wood at a rotation age of 50 years.
Foresters should have a good knowledge of timber grading and of the defects likely to cause degrade, in order to prescribe proper tending for the next rotation of this species.