Examination of mean top height definitions and height estimation equations for Pinus radiata in New Zealand.

Authors: R. C. Woollons
Publication: New Zealand Journal of Forestry, Volume N.Z.J.For. 2003, Issue N.Z.J.For. 48(3) 2003, pp 15-18, Nov 2003
Publisher: New Zealand Institute of Forestry

Abstract: For Pinus radiata in New Zealand mean top height is essentially defined and calculated via one definition and the so-called Petterson equation. A study shows that changing the definition to one used overseas has very little impact on top height values. The Petterson model appears to give unbiased estimates of tree height.
The basic relationship between tree height and diameter is not particularly precise, especially at low stockings. To ensure a satisfactory model, it is important that the sample trees have a wide range in diameter.
Changing the power parameter in the Petterson equation has a negligible effect. Adopting alternative height/diameter equations gives a minimal improvement in precision in one case but significantly less precision with the other.