New Zealand Journal of Forestry (1968) 13(2): 203–219
©New Zealand Institute of Forestry
Initial Spacing and Financial Return of Pinus radiata on Coastal Sands
On the basis of measurements recorded in the Woodhill spacing trials (A35) and of the current Woodhill (piece-size dependent) stumpage rates, the financial returns for each of seven initial spacings (6 X 6, 8 X 8, 12 X 12, 16 X 16, 10 X 6, 12 X 6 and 10 x 8 ft) were determined for two tending regimes. Costs of establishment and early silviculture for each spacing were estimated, and these, together with the anticipated returns, were used to calculate the land expectation value (LEV) for several economic models at compound interest rates of 3%, 5% and 8%.
Of the models analysed, the 6 X 6 ft spacing was, without exception, the least profitable, giving LEVs, at 5% compound interest, of the order of $50-$60 an acre lower than those of the most profitable spacing. The 8 X 8ft spacing, although more profitable than the 6x6, was never as profitable as any of the wider spacings. These wider spacings (12 X 12, 16 x 16, 10 x 6, 12 x 6, 10 x 8 and almost certainly the 10 x 10 ft had it been included) all showed remarkable similarity in their calculated net returns; but the values for the 16 x 16 ft and possibly the 12 X 12 ft were considered over-optimistic. It was concluded that, so long as the adopted initial spacing is within the range 10 x 6 to 12 x 12 ft, higher net returns can be anticipated. Aspects which need closer investigation are the effects of spacing on branch size and malformation; but, unless the effects are found to be more marked than present evidence suggests, there is no economic justification for close initial spacing on the coast at sands.