B) Calculating below-ground biomass (root biomass)
In order to calculate root biomass, we used equation 4, in which RGB stands for below-ground biomass and AGB stands for above-ground biomass (sum of trunk and crown biomass) (West and West, 2009, Ximenes et al., 2008, Xue et al., 2016).
\begin{equation} BGB=Volume\ AGB\ \times 0.2\text{\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ }Eq.4\nonumber \\ \end{equation}