Response of thirty- forty-year-old retarded radiata pine stands in Northland to aerial appilcation of phosphate

Authors: J.G. Rawson
Publication: New Zealand Journal of Forestry, Volume N.Z.J.For. 1972, Issue N.Z.J.For. 17(1) 1972, pp 101-107, May 1972
Publisher: New Zealand Institute of Forestry

Abstract: Yield plot data show that improved growth of retarded radiata pine (Pinus radiata D.Don), thirty to forty years old, on a phosphate-deficient Northland site, was obtained by aerial topdressing with superphosphate at rates of between 0.9 and 1.6 tonnes per hectare. Applications varied from a single heavy dressing to several light ones, one to three or more years apart. Increases in diameter growth rate exceeding 500% have been recorded, and mean annual increment has shown a sharp upward trend, approaching in some cases the m.a.i. expected for thrifty stands on good sites.