Establishment of Individual Biomass Equations for Caragana korshinskiiand Armeniaca sibirica in Inner Mongolia

Objective  Aiming at the incompatibility of shrub biomass models between total biomass and components, or above- and below-ground biomass, the authors attempted to develop compatible shrub biomass models using the approach of simultaneous equations. Method  Based on the individual biomass mensuration data of two common shrub species, Caragana korshinskii and Armeniaca sibirica, in the Inner Mongolia in China, the approach of nonlinear error-in-variable simultaneous equations was used to establish compatible above- and below-ground biomass models and root-to-shoot ratio model. Result  The results are as follows: 1.The determination coefficients of above-ground biomass models based on canopy area and amount of stem (or mean height of stem) were higher than 0.67, but those of below-ground biomass models were relatively lower, and that for A. sibirica was only 0.36. 2.The mean prediction precisions of above- and below-ground biomass models for the two species were above 80%, and that of whole biomass model for A. sibirica was above 86% while that for C. korshinskii was above 92%. Conclusion  It could be concluded that for tufty shrub species without obvious trunk, the canopy area was the most important factor related to shrub biomass, whether above- or below-ground biomass modeling, and the next was the amount or mean height of stems; the effective approach to solve the problem of incompatibility among different biomass was using nonlinear error-in-variable simultaneous equations to develop compatible above- and below-ground biomass models and root-to-shoot ratio model; and the biomass models developed here could be applied in shrub biomass estimation for the two species in the Inner Mongolia.