Stem volume equations for valuable timber species in Mozambique

Abstract

Development of stem volume for umbrella-shaped crown trees remains a big challenge for efficient use of forest resources in Mozambique. In this study, species-specific stem volume equations were developed for the first time for three of the most important timber species in Mozambique: Afzelia quanzensis Welw. (Chanfuta), Millettia stuhlmannii Taub. (Jambire) and Pterocarpus angolensis D.C. (Umbila). The study was carried out at three locations in Mozambique: Inhaminga, Mavume and Tome covering 58 trees from which, 24 of Chanfuta, 15 of Jambire and 19 of Umbila. The volume of the sampled stem sections (logs) was calculated using Smalian’s formula, where stem volume total was obtained through the sum of the respective defined sections. Using a nonlinear procedure, different volume models were tested for each tree species independently. The coefficient of the determination of the tested equations in the tree species ranged from .90 to .95, making the equations potential candidate models for the stem volume equations object of the study. Based on the statistical parameter analysis, the best fit nonlinear power equations was Equation 2 with the lowest AICc and lowest average absolute bias. The stem volume for the studied species is better explained by models including both diameter and height as explanatory variables.

Keywords

Afzelia quanzensis; Chanfuta; commercial volume; power equation models; Millettia stuhlmannii; Jambire; miombo woodland; Pterocarpus angolensis; Umbila

Published in

Journal of Sustainable Forestry
2015, volume: 34, number: 8, pages: 787-806

SLU Authors

• Mate, Rosta

  • Eduardo Mondlane University (UEM)

• Johansson, Tord

  • Department of Energy and Technology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Forest Science

Publication identifier

• DOI: https://doi.org/10.1080/10549811.2015.1039043

Permanent link to this page (URI)

https://res.slu.se/id/publ/68694