New Zealand Journal of Forestry (1973) 18(1): 104–108
©New Zealand Institute of Forestry
The Kaingaroa air sowing era, 1960-71.
H. H. Levack
From 1960 to 1911 inclusive, 6500 ha were air sown at Kaingaroa with Pinus radiata. Unsatisfactory seed application, seed predation and seedling frost-back were soon defined as problems. By 1968 the attitudinal and topographic limitations of sites suitable for air seeding had been described, but it was resolved that all areas sown would later have to be supplemented by planting. Improvements in controlling seed distribution from aircraft included the development of a modified helicopter seed slinger, and a new roller device to meter seed flow from fixed-wing aircraft. Seed frequency patterns across the swath sown and flight line espacement were rationalized for a fixed-wing aircraft with roller meter device, and navigational aids to facilitate flying were also developed. But analysis covering genetic gain, opportunity value, frost risk and tending expenses, together with direct costs, has resulted in a decision to curtail air sowing on Kaingaroa cutovers.