Volume and Aboveground Biomass Models for Dry Miombo Woodland in Tanzania

Ezekiel Edward Mwakalukwa,Henrik Meilby,Thorsten Treue

doi:10.1155/2014/531256

Ezekiel Edward Mwakalukwa, Henrik Meilby + Show 1 more

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https://doi.org/10.1155/2014/531256

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Abstract

Tools to accurately estimate tree volume and biomass are scarce for most forest types in East Africa, including Tanzania. Based on a sample of 142 trees and 57 shrubs from a 6,065 ha area of dry miombo woodland in Iringa rural district in Tanzania, regression models were developed for volume and biomass of three important species,Brachystegia spiciformisBenth. (n = 40),Combretum molleG. Don (n = 41), andDalbergia arbutifoliaBaker (n = 37) separately, and for broader samples of trees (28 species,n = 72), shrubs (16 species,n = 32), and trees and shrubs combined (44 species,n = 104). Applied independent variables were log-transformed diameter, height, and wood basic density, and in each case a range of different models were tested. The general tendency among the final models is that the fit improved when height and wood basic density were included. Also the precision and accuracy of the predictions tended to increase from general to species-specific models. Except for a few volume and biomass models developed for shrubs, all models hadR2values of 96–99%. Thus, the models appear robust and should be applicable to forests with similar site conditions, species, and diameter ranges.

Highlights

Standing volume and aboveground biomass (AGB) are the two main measures of forest stocking that are typically considered within the framework of sustainable forest management and for carbon accounting purposes [1, 2]
Based on a sample of 142 trees and 57 shrubs from a 6,065 ha area of dry miombo woodland in Iringa rural district in Tanzania, regression models were developed for volume and biomass of three important species, Brachystegia spiciformis Benth. (n = 40), Combretum molle G
To assess the increase in accuracy achieved in Gangalamtumba Village Land Forest Reserve (GVLFR) by the new models, 10 different previously published volume and biomass models for miombo woodlands were tested on the datasets prepared in this study

Summary

Introduction

Standing volume and aboveground biomass (AGB) are the two main measures of forest stocking that are typically considered within the framework of sustainable forest management and for carbon accounting purposes [1, 2]. Accurate estimation of tree volume and forest biomass is crucial for assessing expected yields from commercial and subsistence harvesting It is important for carbon storage assessment in relation to global climate change mitigation measures [3, 4]. The selection of an appropriate allometric equation is a key element in the accurate estimation of forest yield and stand productivity as well as carbon stocks and changes in stocks [7, 8]. Such equations often produce biased results when applied outside the forest area or region where they were developed. If high accuracy is required for quantification and verification of a particular forest’s carbon storage or for other management purposes, it is recommended to develop local biomass and volume equations or at least to harvest and measure a few trees, representing the range of tree sizes typically found in the forest, and use these to check the validity of the applied equation under local conditions [1, 9, 10]

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