A) Estimating the above-ground biomass
The above-ground biomass included trunk and crown biomass. Estimating
their biomass are as follows:
Calculating trunk biomass: In order to estimate biomass
of tree trunk, basal area of a tree was calculated using Eq. 1, their
volume was calculated through Eq. 2, and finally, the biomass of a tree
was obtained by Eq. 3 in kilogram (Ponce-Hernandez et al., 2004).
\begin{equation}
A_{b}=\pi\times r^{2}\text{\ \ \ \ \ }Eq.1\ \nonumber \\
\end{equation}\begin{equation}
V=A_{b}\times H\times K_{c}\ \ \ \ \ \ \ \ \ \ \ \ \ \ Eq.2\text{\ \ }\ \nonumber \\
\end{equation}\begin{equation}
Biomass=\text{AGB}=V\times WD\times 1000\ \ \ \ \ \ \ \ Eq.3\nonumber \\
\end{equation}Where \(\pi\) is 3.14, \(A_{b}\)is a basal area
(m2 ), r is tree radios(meter ), H is the
height of a tree(meter) , WD is tree density
(gr/cm3 ), V is the volume of a tree
(cm3 ), \(K_{\text{c\ }}\)is a coefficient that
depends on the site (In most of the studies associated to the biomass in
Northern jungle of Iran, the coefficient was considered 0.54)
(Namiranian, 2003, Peichl and Arain, 2006, Ponce-Hernandez et al.,
2004).
In equation 3, the variable of dried wood density
(gr/cm3 ) was calculated based on the dried
weight (gram ) to the volume (cm3 ); M is
weight of dry wood (gram ) and V is the volume of the wood
(cm3 ), and WD stands for dried wood density in
term of a gram per cm3 (Henry et al., 2010, Varamesh
et al., 2010).
Since the density of dry wood of trees was not measured in the study
area, then for each species in the area, we used the average amount of
wood density measured in the previous study (Brown, 1997, McPherson et
al., 2016).
- Calculating crown biomass (tree branches): Crown size
is one of the basic variables in allometric equations to estimate the
tree biomass. The above-ground biomass is summation of the trunk biomass
and crown biomass (leaf and branches). There are different methods to
calculate crown biomass in jungle areas (McPherson et al., 2016; (Dong
et al., 2016, Negi et al., 1995, Ximenes et al., 2008, Xue et al.,
2016). As represented in table 1, previous studies determined the
proportion of crown biomass related to the total biomass (root, trunk,
and crown) for conifer and broadleaf species (Dong et al., 2016, Negi et
al., 1995, Ximenes et al., 2008, Xue et al., 2016).