The nutrition of Douglas fir at Narbethong.  D. W. Flinn and P. Hopmans.  July 1976.  7 pp. (unpubl.)

SUMMARY

Recent planting of Douglas-fir commenced at Narbethong in 1971, and since then almost all of the seedlings have failed to establish satisfactorily. Mortality has occasionally been high, but always variable; needle chlorosis and needle cast have been severe, and growth always unsatisfactory.

This report deals primarily with a fertiliser experiment undertaken to investigate nutritional aspects of Douglas-fir establishment in the area. The effects of fertilisers containing nitrogen, phosphorus, potassium and trace elements, some alone and some only in combination with others, were followed. Uptake of nutrients by fertilised and unfertilized trees was also studied.

The results showed that mortality of the young trees was not associated with their nutrition, but other studies not described in this report suggest that close attention should be given to nursery practices used to raise Douglas-fir at Narbethong if high or variable mortality is to be avoided. The practices of late lifting and root pruning immediately prior to planting are bad.

On the other hand, needle chlorosis, needle cast and poor early growth were shown to be due to severe phosphorus deficiency. Substantial uptake of phosphorus following the application of fertiliser was associated with the development of a healthy tree crown and satisfactory early growth. In fact, all of the symptoms associated with poor health did not appear when a phosphorus fertiliser was applied.

For satisfactory establishment of Douglas-fir at Narbethong late lifting and root pruning immediately prior to planting should be avoided, and 50 g of Confos should be applied to each seedling in the field immediately following planting.

Also published:

Flinn, D.W. and Hopmans, P. (1976)  Nutrition of Pseudotsuga menziesii at Narbethong.  For. Comm. Vic., For. Tech. Pap. 24: 19-22.