Species-Specific Allometric Equations for Predicting Belowground Root Biomass in Plantations: Case Study of Spotted Gums (Corymbia citriodora subspecies variegata) in Queensland

Spotted gum (Corymbia citriodora spp. variegata; CCV) has been widely planted, a wide natural distribution, and is the most important commercially harvested hardwood species in Queensland, Australia. It great capacity to sequester carbon, thus reducing impact of CO2 emissions on climate. Belowground root biomass (BGB) plays an role as carbon sink terrestrial ecosystems. To explore potential accumulation belowground, we developed validated models for CCV plantations Queensland. The roots twenty-three individual trees (size range 11.8–42.0 cm diameter at breast height) from three sites were excavated 1-m depth weighed obtain BGB. Weighted nonlinear regression reliable estimating evaluate candidate models, data set was cross-validated with 70% used training 30% testing. cross-validation process repeated 23 times validation averaged over iterations. best model predicting spotted BGB based single parameter, height (D) independent variable. equation = 0.02933 × D2.5805 had adjusted R2 0.854 mean absolute percentage error 0.090%. This tested against published equations; findings this are discussed. Our recommended allow improved estimates species.