The accuracy of species-specific allometric equations for estimating aboveground biomass in tropical moist montane forests: case study of Albizia grandibracteata and Trichilia dregeana

Abstract

Background: Application of allometric equations for quantifying forests aboveground biomass is a crucial step related to efforts of climate change mitigation. Generalized allometric equations have been applied for estimating biomass and carbon storage of forests. However, adopting a generalized allometric equation to estimate the biomass of different forests generates uncertainty due to environmental variation. Therefore, formulating species-specific allometric equations is important to accurately quantify the biomass. Montane moist forest ecosystem comprises high forest type which is mainly found in the southwestern part of Ethiopia. Yayu Coffee Forest Biosphere Reserve is categorized into Afromontane Rainforest vegetation types in this ecosystem. This study was aimed to formulate species-specific allometric equations for Albizia grandibracteata Tuab. and Trichilia dregeana Sond. using the semidestructive method. Results: Allometric equations in form of power models were developed for each tree species by evaluating the statistical relationships of total aboveground biomass (TAGB) and dendrometric variables. TAGB was regressed against diameter at breast height (D), total height (H), and wood density (ρ) individually and in a combination. The allometric equations were selected based on model performance statistics. Equations with the higher coefficient of determination (adj.R 2), lower residual standard error (RSE), and low Akaike information criterion (AIC) values were found best fitted. Relationships between TAGB and predictive variables were found statistically significant (p ≤ 0.001) for all selected equations. Higher bias was reported related to the application of pan-tropical or generalized allometric equations. Conclusions: Formulating species-specific allometric equations is found important for accurate tree biomass estimation and quantifying the carbon stock. The developed biomass regression models can be applied as a species-specific equation to the montane moist forest ecosystem of southwestern Ethiopia.

Allometric Equations for the Biomass Estimation of Calophyllum inophyllum L. in Java, Indonesia

“…In this regard, the implementation of reforestation and afforestation in degraded lands should account for CO 2 reduction outcomes for international commitments. Accurate CO 2 emissions by sources and removals by sinks are essential for measuring, reporting, and verifying (MRV) the Warsaw REDD+ Framework [1][2][3] and for implementing Nationally Determined Contributions (NDC) under the Paris Agreement [4,5].…”

allodb: An R package for biomass estimation at globally distributed extratropical forest plots

“…For example, pantropical models based on large datasets (Chave et al., 2005; Feldpausch et al., 2011) give reliable results with smaller errors compared to regional models (Rutishauser et al., 2013). Second, the precision of predictions can be improved by using equations calibrated with trees from a similar taxonomic group, and that grew in similar climatic conditions (Daba & Soromessa, 2019; Ngomanda et al., 2014; Roxburgh et al., 2015). In practice, these two principles are in conflict, in that taxa‐ or location‐specific allometries are usually constructed based on a much lower sample size than generic allometries.…”

Allometric Equations For Ethiopian Acacia Species 

“…According to Henry, Picard [23], reviews of biomass models in sub-Saharan Africa, 63 models have been developed in Ethiopia, which focused only on six allometric equations, of which 70% of the models were developed for eucalypt species [24]. However, following the review of Henry, Picard [23], there have been attempts to develop local species-specific allometric equations for estimating AGB of trees in different parts of Ethiopia in recent studies [24], such as Tesfaye, Bravo-Oviedo [16], Kebede and Soromessa [25], Daba and Soromessa [26] and Daba and Soromessa [27] but still, they are not sufficient in respective of vegetation types and agro-ecology of Ethiopia.…”

“…Therefore, the semi-destructive sampling method was used for modeling AGB of the indigenous trees, apply in degraded woodland and important in key conservation areas where cutting is prohibited [30]. Publications on semi-destructive methods have been increasing in recent year in Ethiopia including the work of Worku and Soromessa [31] in Wof-Washa dry Afromontane forest, Daba and Soromessa [27], [26], in Biosphere Reserve forest of southwestern Ethiopia and Kebede and Soromessa [25] in Mana Angetu moist Afromontane forest of Ethiopia and Mahmood, Siddique [32] in Hill zone of Bangladesh.…”