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

Abstract

Allometric equations for calculation of tree above‐ground biomass (AGB) form the basis for estimates of forest carbon storage and exchange with the atmosphere. While standard models exist to calculate forest biomass across the tropics, we lack a standardized tool for computing AGB across boreal and temperate regions that comprise the global extratropics. Here we present an integrated R package, allodb, containing systematically selected published allometric equations and proposed functions to compute AGB. The data component of the package is based on 701 woody species identified at 24 large Forest Global Earth Observatory (ForestGEO) forest dynamics plots representing a wide diversity of extratropical forests. A total of 570 parsed allometric equations to estimate individual tree biomass were retrieved, checked and combined using a weighting function designed to ensure optimal equation selection over the full tree size range with smooth transitions across equations. The equation dataset can be customized with built‐in functions that subset the original dataset and add new equations. Although equations were curated based on a limited set of forest communities and number of species, this resource is appropriate for large portions of the global extratropics and can easily be expanded to cover novel forest types.

Topographically driven microclimatic gradients shape patterns of forest structure, diversity, and composition at a forest-grassland transition zone

“…To assess patterns of forest structure and diversity along the topographic gradients, we ran separate analyses on (a) adults and saplings (referred to together hereafter as ‘trees’; DBH ≥1 cm), and (b) seedlings (DBH < 1 cm) of woody species. To quantify forest structure and diversity, we calculated tree stem density, total basal area, total AGB, and species richness and diversity for trees in each quadrat using functions in the ‘fgeo’ (Lepore et al 2019), ‘allodb’ (Gonzalez-Akre et al, 2021), and ‘vegan’ (Oksanen et al 2020) packages. Stem density was the number of individual trees per quadrat.…”

“…Total quadrat basal area (m 2 ) was calculated from DBH (cm) as Σ 𝜋 × (DBH) 2 /(4×10,000 cm/m 2 ). The 'allodb' package uses a database of species and genus-specific allometric equations and wood densities, combined with DBH measurements, to estimate the AGB of all stems of an individual in kg (Gonzalez-Akre et al, 2021), which were summed for trees in each quadrat to obtain the quadrat-level AGB. We scaled tree stem density, basal area, and AGB to a per ha basis.…”

Joint effects of climate, tree size, and year on annual tree growth derived from tree‐ring records of ten globally distributed forests

“…Once DBH had been reconstructed, we estimated basal area (BA = r 2 , where r is radius) and aboveground biomass (AGB). Biomass allometries for temperate and tropical species were calculated using the R packages allodb (Gonzalez‐Akre et al, 2021 ) and BIOMASS (Réjou‐Méchain et al, 2017 ), respectively. We then calculated basal area increment (BAI = Ba y+1 ‐BA y , where y is year) and aboveground biomass growth increments (ΔAGB = AGB y+1 ‐AGB y ).…”

Scale‐dependent effects of species diversity on aboveground biomass and productivity in a subtropical broadleaved forest on Mt. Huangshan

“…Therefore, few studies have been conducted on the relationship between species diversity and biomass/productivity in forest ecosystems, especially in forestry dynamics plot in subtropical forest. Allometric growth equations based on 701 woody species determined within 24 large‐scale forest dynamics plots (Forest Global Earth Observatory, ForestGEO) facilitated the estimation of biomass of species in different forest ecosystems, especially subtropical evergreen broadleaved forests (Gonzalez‐Akre et al, 2021 ). The advantage of this method is that variance caused by sample size, climate, and taxonomy is considered and incorporated into the allometric equation in a weighted manner (Gonzalez‐Akre et al, 2021 ).…”

“…Allometric growth equations based on 701 woody species determined within 24 large‐scale forest dynamics plots (Forest Global Earth Observatory, ForestGEO) facilitated the estimation of biomass of species in different forest ecosystems, especially subtropical evergreen broadleaved forests (Gonzalez‐Akre et al, 2021 ). The advantage of this method is that variance caused by sample size, climate, and taxonomy is considered and incorporated into the allometric equation in a weighted manner (Gonzalez‐Akre et al, 2021 ). On the other hand, we paid too much attention to the effects of species richness on ecosystem function, which alters densities due to interactions between species being overlooked.…”