Bosque (Valdivia)  vol.37 no.2; Abstract: S0717-92002016000200022
Revistas Electrónicas UACh
Web Sistema de Bibliotecas UACh
Formulario de Contacto Revistas Electrónicas UACh (OFF)
Revistas Electrónicas UACh - Bosque (Valdivia)
vol.37 no.2Abundance of Apodemus spp. varies by stand age in coppice-originated oak forest, Thrace, Turkey  author indexsubject indexsearch form
Inicio revistaalphabetic serial listing  

Bosque (Valdivia)
On-line ISSN 0717-9200

  How to cite this article
  Add to favorites article
  Send to E-mail


ARTURI, Marcelo. Evaluation of Bitterlich angular count sampling in different spatial patterns and diametric distributions by the means of simulations. Bosque (Valdivia), 2016, vol.37, no.2, p.431-437. ISSN 0717-9200.

The precision and accuracy of Bitterlich angular count (BAC) for the estimation of basal area density could depend on diametric distribution since the inclusion probability of the trees increases with their basal area. Trees spatial pattern can also influences since point-tree distances determine their inclusion in the sample. In this study, the precision and bias of BAC under different diametric distribution and spatial patterns were evaluated by the means of simulations. Normal and lognormal diametric distributions were simulated with basal area density ranging between 30-33 m2 ha-1. These diametric distributions were simulated in three spatial patterns: regular, random and clumped yielding six combinations. A seventh class was simulated with bimodal diametric distribution and a mixed spatial pattern: clumped for small trees and random for large trees. Bias was less than 0.10 m2 ha-1 except for clumped pattern with lognormal diametric distribution and mixed pattern. In these cases bias tended to be negative (-0.15 a -0.25 m2 ha-1). The lowest mean absolute deviation (MAD) was observed for the regular pattern 3-7 %. In the clumped pattern it ranged 7-10 % and 8-11 % in the mixed. MAD tended to be slightly lower in the normal distribution than in lognormal in the regular spatial pattern but the reverse trend was observed in the clumped pattern. In practical terms BAC yields null bias and low MAD with a low intensity sampling for a wide variety of stand structures.

Keywords: bias; basal area; DBH; forest structure; forest biometry.

        · abstract in spanish     · text in spanish     · pdf in spanish

© 2019 • Facultad de Ciencias Forestales, Universidad Austral de Chile
Teléfono/Fax: 56 63 221998 • Casilla 567 • Campus Isla Teja S/N • Valdivia • Chile