Early performance of first generation seed orchard stock at Omataroa Forest.

Authors: M. Cleland
Publication: New Zealand Journal of Forestry, Volume N.Z.J.For. 1985, Issue N.Z.J.For. 30(1) 1985, pp 45-53, May 1985
Publisher: New Zealand Institute of Forestry

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Abstract: Compartment 22, Omataroa Forest, consists of 14 ha of first-generation seed orchard stock and 63 ha of non-orchard stock. Both areas were planted in 1973.
Recent measurements showed that no increase in vigour was evident in seed orchard stock but a considerable reduction in leader malformation seems to have been achieved. Seed orchard stock also had more highly multinodal trees and a significant increase in the number of branches per tree. However, indicies of branch size and internode length were not different from those of non-orchard stock, and no statistically significant differerences were shown for bole straightness or for the frequency of stem cones.
A production thinning operation began in August 1983 to thin this compartment to 250 stems/ha and the volume extracted from seed orchard and non-orchard areas was compared. Seed orchard plots achieved a 16% increase in mean volume per piece extracted. This gain is probably due to reduced leader malformation in seed orchard stock, resulting in a higher conversion from standing volume to merchantable volume.

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