The effects of spacing on the rate of machine planting.  W. D. Incoll, J. E. Opie and B. C. Aeberlie.  August 1979.  11 pp. (unpubl.)

SUMMARY

This study examined the effect of initial density and rectangularity (the ratio of within row to between row spacing) on the rate of machine planting of Pinus radiata seedlings.

A factorial design, employing three levels of density (749, 1683, 4305 trees per hectare) and three levels of rectangularity (1:1, 1:2, 1:4), was replicated three times in each of two localities. Typical planting sites of moderate slope were employed and the planting was carried out by experienced operational crews. Work study methods were used to obtain an area planted per net crew hour for each treatment combination.

The results are expressed in a model designed for interpolative interpretive and extrapolative use. The data indicate that rate of planting increased as rectangularity was increased from 1:1 to 1:4 and that the increase was substantially greater for medium and lower densities.

Possible uses of the model are discussed and examples show that substantial cost savings are possible with moderate increases in rectangularity (e.g. at 1683 trees/ha changing spacing from 2.4 x 2.4 m to 3.7 x 1.8 m provides an estimated cost saving of 23%). The model also shows that planting costs are very sensitive to initial density (e.g. when spacing falls from 2.4 x 2.4 to 2.1 x 2.1, cost per hectare increases by 27%).

Also published:

Incoll, W.D., Opie, J.E. and Aeberlie, B.C. (1980)  Effects of spacing on rate of machine planting of radiate pine.  Aust. For. 42 (3): 176-80.