Estimating biomass of Larix principis-rupprechtii Mayr. plantations in northern China

Generally,biomass estimation factors are used to estimate regional forest biomass,including biomass conversion and expansion factor (BCEF),biomass expansion factor (BEF),basic wood density (WD) and root: shoot ratio (RSR). Recent studies have showed the values of biomass estimation factors had large uncertainties,which were obtained using those functions between biomass estimation factors and stand measured variables (e. g. stand age,diameter and tree height). Essentially,biomass estimation factors describe the allometries relationship between shoot biomass (MA) and standing volume (V),between shoot biomass (MA) and stem biomass (MS),and between root biomass (MR) and shoot biomass (MA). To reduce the uncertainties in regional forest biomass estimates,we took Larix principis-rupprechtii Mayr. plantations as a case study,developed region-specific allometric equations for MA vs. V,MA vs. MS,and MR vs. MA,and analyzed their differences among regions ( i. e. Guandi Mountain,middle-alpine zone of Wutai Mountain,basin zone of Wutai Mountain and Saihanba Forest Region). Results showed that there were significant differences among region-specific allometric equations for MA vs. V (p 0. 05) as well as for MA vs. MS(p 0. 05),but there was no significant differences among region-specific allometric equations for MR vs. MA(p 0. 05). Even so,allometric equations for entire regions had good prediction accuracy (R2 0. 90). Considering significant differences among regionspecific allometric equations,it had better develop and select region-specific allometric equations. Moreover,regional forest biomass estimates using these allometric equations are better than using the functions between biomass estimation factors and stand measured variables.