Allometry equations are used to extrapolate the remotely sampled data to any larger area using the mathematical formulas. By using Allometry equations, the difficult variables associated with the measurement of wood and leaf biomass from easy-to-measure tree parameters, such as the stem diameter (at tree base or breast height), tree height or canopy and tree’s crown width, can be easily calculated (Chidumayo 1997; Netshiluvhi and Scholes 2001; Santos et al. 2002). The Allometric equations are commonly derived by making use of the regression analysis of the relationship between the weight in dry form obtained from the destructive sampling (as described above) and the measured dimensional parameters of the fallen trees (De Gier 2003).

The equations are expressed in power law form or logarithmic form as shown in Eqs. 12.10 or 12.11 (Japanese International Cooperation Agency JICA 2005):

у = b * лл (12.10)

or

ln y = ln b + a ln x (12.11)

Where y is the weight of tree in kilograms, b is the allometric coefficient, a is the allometric exponent and x is the measured tree parameter which is significantly related to tree biomass such as basal diameter in the units of centimetres (cm).