From "Summary" "Results obtained" "In the first place, the data in Table 11.2 indicated that when the site index is as low as 64 [= the mean height in feet at 20 years of the 100 biggest-diameter trees per acre], radiata-growing cannot be expected to be profitable in the Western Cape ? The treatment which proved the most profitable for both site indices 80 and 99 was to plant the trees at an espacement of 9 feet [2.74 m], to take out respectively 60, 50 and 40 per cent of the trees in thinnings at 6, 11 and 16 years, and to clearfell at 21 years.
Such a treatment may not give as good a sawtimber as could be obtained with lighter thinnings and a longer rotation, but this does not alter the fact that it was found to give a much greater profit. The standard treatment currently applied in the state-owned radiata plantations in the Western Cape no doubt produces a greater proportion of high-quality sawtimber than the optimal treatment described above, but it was found to give a negative net land expectation value [net present value] at average timber values and silvicultural costs." (Pages 216/17)