Allometric Models Based on Bayesian Frameworks Give Better Estimates of Aboveground Biomass in the Miombo Woodlands

Shem Kuyah,Gudeta Sileshi,Todd Rosenstock

doi:10.3390/f7020013

Shem Kuyah, Gudeta Sileshi + Show 1 more

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https://doi.org/10.3390/f7020013

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Abstract

The miombo woodland is the most extensive dry forest in the world, with the potential to store substantial amounts of biomass carbon. Efforts to obtain accurate estimates of carbon stocks in the miombo woodlands are limited by a general lack of biomass estimation models (BEMs). This study aimed to evaluate the accuracy of most commonly employed allometric models for estimating aboveground biomass (AGB) in miombo woodlands, and to develop new models that enable more accurate estimation of biomass in the miombo woodlands. A generalizable mixed-species allometric model was developed from 88 trees belonging to 33 species ranging in diameter at breast height (DBH) from 5 to 105 cm using Bayesian estimation. A power law model with DBH alone performed better than both a polynomial model with DBH and the square of DBH, and models including height and crown area as additional variables along with DBH. The accuracy of estimates from published models varied across different sites and trees of different diameter classes, and was lower than estimates from our model. The model developed in this study can be used to establish conservative carbon stocks required to determine avoided emissions in performance-based payment schemes, for example in afforestation and reforestation activities.

Highlights

The miombo is the largest continuous dry deciduous forest in the world
Trees harvested for development of allometric models thoroughly captured the variability of the miombo woodland vegetation in Malawi in terms of species diversity and tree sizes
This is important because the parameters of allometric models have been shown to vary with tree species and ecological conditions [29]

Summary

Introduction

The miombo is the largest continuous dry deciduous forest in the world. It extends across much of Central, Eastern and Southern Africa including parts of Angola, the Democratic Republic of Congo, Malawi, Mozambique, Tanzania, Zambia and Zimbabwe [1]. The woodlands are rich in plant diversity and have the potential to contain a substantial amount of carbon, up to 39.6 Mg ha in aboveground biomass [2,3,4] Though this is only 20% of Sub-Saharan African equatorial forests, which are estimated to stock between 72 and 152 tonnes of carbon per hectare [5], this carbon pool could be significant considering that miombo covers 2.7 million km2 [6].

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