Stem form and volume of Japanese larch (Larix leptolepis Gord.) in the Netherlands

J. van Soest

Research output: Thesisinternal PhD, WU

Abstract

The following conclusions could be made:

If for volume table construction, the form factor (f), instead of the volume (v), is used as the dependent variable, better results are obtained.

It matters little whether f is estimated from the diameter (d), or from d and height (h) together.

Estimating v (or, if more convenient, the so-called form height fh) from d only, on the other hand, leads to much greater inaccuracies.

Estimating v of f`g (g = basal area) from h only is most inaccurate.

From an accuracy point of view graphical and mathematical methods must be considered equivalent.

In actual practice, f can, for most measurements of standing timber, be derived with sufficient accuracy from a smoothing of f on d or from a mathematical solution with the aid of f = a + b log d 1,3 . One should however expect deviations of the f of a stand from the regression line, of up to 10 %.

f can be much better estimated by using the regression equation f = a + b1 log d 1,3 + b, log d 6 + b 3 log h. Then the deviations of stands are < 3 % (dx = d at x meter height).

The data investigated indicate that close initial spacings and medium to heavy thinnings lead to relatively high f values.

The error caused by using f with g as the stand f, is negligible.

It is not likely that the functions found will also apply to other tree species.

Original languageEnglish
QualificationDoctor of Philosophy
Awarding Institution
  • Wageningen University
Supervisors/Advisors
  • Becking, J.H., Promotor, External person
Award date17 Apr 1959
Place of PublicationWageningen
Publisher
Publication statusPublished - 1959
Externally publishedYes

Keywords

  • forestry
  • trees
  • forests
  • measurement
  • dimensions
  • volume
  • larix kaempferi
  • forest stands

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