Allometric equations for estimating belowground biomass of Androstachys johnsonii Prain

Abstract

BackgroundThe belowground component of the trees is still poorly known because it needs labour- and time-intensive in situ measurements. However, belowground biomass (BGB) constitutes a significant share of the total forest biomass. I analysed the BGB allocation patterns, fitted models for estimating root components and root system biomasses, and called attention for its possible use in predicting anchoring functions of the different root components.ResultsMore than half and almost one third of BGB is allocated to the lateral roots and to the root collar, respectively. More than 80% of the BGB is found at a depth range of 9.6–61.2 cm. As the tree size increased, the proportion of BGB allocated to taproots decreased and that allocated to lateral roots increased. All independent models performed almost equally, with the predictors explaining, on average, 98% of the variation in the BGB.ConclusionsIt was hypothesised that BGB allocation patterns are a response of the anchoring functions of the tap and lateral roots and therefore, root component biomass models can be used as a methodology to predict anchoring functions of the different root components. Based on the fact that all models performed almost equally, the models using either diameter at breast height (DBH) exclusively as a predictor should be preferred, as tree height is difficult to measure. Models using the root collar diameter (RCD) only should be preferred when the tree is found cut down, as sometimes the RCD is affected by root buttress. Given the large sample size, the validation results, and the coverage of a wide geographical, soil and climatic range, the models fitted can be applied in all A. johnsonii stands in Mozambique.

Live above- and belowground biomass of a Mozambican evergreen forest: a comparison of estimates based on regression equations and biomass expansion factors

“…The easternmost Mecrusse forest patches, located in Mabote, Funhalouro, Panda, Mandlakaze, and Chibuto districts, were defined as the study area and encompassed 4,502,828 ha (Dinageca 1997), of which 226,013 ha (5 %) were Mecrusse woodlands. Maps showing the area of natural occurrence of mecrusse in Inhnambane and Gaza provinces and the study area, along with detailed description of the species and the forest type can be found in Magalhães and Seifert (2015c) and Magalhães (2015).…”

“…In the second phase, 93 A. johnsonii trees (DBH range: 5-32 cm; height range: 5.69-16 m) were randomly selected from those analysed during the first phase for destructive measurement of tree component biomass along with the variables from the first phase. Maps showing the distribution of the 23 randon plots in the study area and in the different site classes are shown by Magalhães and Seifet (2015c) and Magalhães (2015).…”

“…Tree components were sampled and the dry weights estimated as desbrided by Magalhães and Seifert (2015, a, b, c, d, e) and Magalhães (2015).…”

Estimates of Tree Biomass, and Its Uncertainties Through Mean-of-Ratios, Ratio-of-Means, and Regression Estimators in Double Sampling: A Comparative Study of Mecrusse Woodlands

“…The climate throughout the study region is dry tropical, with the exception of humid tropical areas in western Panda and southwestern Mandlakaze districts [22][23][24][25][26][27]; their warm or rainy season occurs from October to March, and their cool or dry season occurs from March to September [23][24][25][26][27]. More description on Androstachys johnsonii Prain and mecrusse woodlands can be foud in Magalhães [28] and Magalhães and Seifert [29][30][31][32].…”

Regional carbon uptake of croplands in Poland between 1960 and 2009

“…Enhanced conversion of residues to SOM results in larger soil organic carbon stocks (Ontl, Schulte 2012;Khedr et al 2017). While carbon in aboveground biomass of crops can be measured easily, belowground biomass can hardly be measured in situ (Houghton et al 2009;Magalhães 2015;Shafea et al 2017), and must therefore be estimated. One possibility of estimating belowground biomass is based on the equations provided in the instructions of the Guidelines for national greenhouse gas inventories (IPCC 2006b).…”