Compatible standing tree volume and above-ground biomass equations for spruce (Picea asperata) in northeastern China

Based on the data of standing tree volume and above-ground biomass for spruce in northeastern China, the compatible standing tree volume equation, above-ground biomass equation, biomass conversion function, and models for each type biomass model were constructed using two methods: direct total-biomass-control and measurement error model. The results showed that: 1) accuracy and mean predicting error (MPE) by above-ground biomass equation were improved significantly by introducing tree height factor; 2) one-variable compatible equations of standing tree volume and above-ground biomass equations for spruce in northeastern China were developed with determination coefficients (R2) of 0.94 and 0.97 respectively, and MPE of 5.36% and 3.55%; 3) bivariate compatible equations for both standing tree and above-ground biomass equations have higher accuracies with R2 of 0.98 and MPE of around 3.06%. This indicates that both one-variable and bivariate compatible models are applicable to estimate the above-ground biomass of spruce forests in northeastern China.