Current problems in the copper nutrition of radiata pine in New Zealand: A review

Abstract

Copper deficiency in radiata pine, that is to say stem and branch twisting associated with low foliar concentrations of Cu, occurs in several well-defined locations in New Zealand. Some recent wind-blown sands and some peat-covered podzol soils are susceptible. Nitrogen and phosphorus fertiliser may stimulate latent Cu deficiency on the podzols, particularly when applied to trees strongly deficient in nitrogen and phosphorus. Copper fertiliser, either as a foliar spray or as a ground application, is effective in controlling malformation. A similar type of stem and branch twisting occurs in trees planted on fertile old agricultural soils. Trees on such soils typically grow very fast and have generally tended to produce high-value clearwood, so this type of malformation severely affects management objectives. Copper concentrations in foliage of affected crops range from 4 to 6 ppm, significantly above the level at which copper deficiency is recognised. Copper fertiliser applied to such a crop increased foliar copper, but had no effect on malformation. There seems, therefore, to be two syndromes, one of which is clearly related to Cu deficiency and treatable; the other, which mimics it, is not at present treatable.