New Zealand Journal of Forestry (1974) 19(1): 13–45
©New Zealand Institute of Forestry
Recent investigations of wood properties and growth performance in Pinus muricata.
C. J. A. Shelbourne
[Cf. FA 35, 2305] There is a need in New Zealand for an exotic tree species better adapted than Pinus radiata to colder, higher-altitude sites and poorer soils but with similar growth rates and utilization characteristics and with good form. The northern, blue-foliaged provenances of P. muricata is most promising. Much of the P. muricata already planted in New Zealand is of the more southern, green-foliaged provenance, and this is inferior to both P. radiata and 'blue' P. muricata in all respects. This paper reviews the results of recent utilization studies and several comparisons of growth of the blue provenance of P. muricata and P. radiata in stands of various ages in New Zealand. P. muricata has the same adult resistance to Dothistroma pini as P. radiata. In general, the two species have similar nursery characteristics, but P. muricata has twice as many seeds per kg and its seedling heights are about 20% less. Wood density in P. muricata shows a much smaller pith-to-bark density gradient, although whole-tree density is similar for both species. The papermaking properties of blue P. muricata are generally good and similar to those of P. radiata. In a comparison of timber grade, P. muricata gave better visual grades and its average stiffness (measured by machine stress-grading) was higher. On sites above 600 m alt., the height of P. muricata exceeded that of P. radiata by 17-28%. Bole straightness was consistently superior in P. muricata. In a comparison of green and blue P. muricata and P. radiata on the same site in Kaingaroa at 45 years of age, the total volume of neighbouring stands was 610, 950, and 1120 m3/ha respectively, with similar stockings of ca. 250 stems/ha.