A Growth Study in Aerially-topdressed Pinus radiata Stand at Riverhead Forest

Authors: D.J. Mead
Publication: New Zealand Journal of Forestry, Volume N.Z.J.For. 1968, Issue N.Z.J.For. 13(2) 1968, pp 229-238, Aug 1968
Publisher: New Zealand Institute of Forestry

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Abstract: A Pinus radiata stand planted in 1927 on phosphate-deficient soil at Riverhead Forest was aerially-topdressed with 5cwt/acre of superphosphate in 1955. The growth of trees in this stand was investigated in 1965.
The trees had grown very slowly after planting. The dressing of superphosphate increased height, diameter and volume remarkably. Larger trees responded more quickly than the smaller trees.
Volume increment has not declined since topdressing. Height increment has now started to decline; phosphate and nitrogen foliar concentrations are below the level considered necessary for adequate growth; the crowns show some deterioration. A gradual reduction of volume increment may therefore be expected, although it may not begin for a few years.

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