ALLOMETRIC EQUATIONS FOR ESTIMATION OF ABOVE GROUND BIOMASS OF Eucalyptus camaldulensis IN MALAWI

Accurate estimates of carbon stocks depend to a greater degree on the availability and adequacy of the allometric equations that are used to estimate tree biomass. A study was conducted to develop allometric equations for estimating above ground biomass of Eucalyptus camaldulensis in Malawi for 2-5 years and 6-10 years age class using destructive sampling method. Katete Forest Plantation was selected for this research. A total of 84 and 78 individual trees from age class of 2-5 years and 6-10 years were randomly selected. Trees were harvested from different diameter class to ensure that the models produced could be a reflection of the diameter class variations in the forest. Various predictors involving diameter at breast height (dbh) and height were run against above ground biomass in regression analysis, R2 adjusted, RMSE and Furnival’s Index of fit (FI) were used for model comparison. All the models showed a strong and highly significant (P<.001) association between above ground biomass and the predictors (R2>.870). Dbh was a better predictor of biomass than height. The best allometric equations for above ground biomass of Eucalyptus camaldulensiswere: AGB=0.284(dbh)2.085 (R2=96.8%; RMSE=0.192; FI=0.19) and AGB=0.009(dbh)3.638 (R2=97.3%; RMSE=0.091; FI=0.09) for age class of 2-5 years and 6-10 years respectively. Comparison of the site specific models in the present study with the generalized model for estimation of biomass for Eucalyptus trees significantly (P<.001) differed. The generalized model underestimated the above ground biomass and had higher relative uncertainty. This indicates a need for site specific equations to be used for accurate estimation of above ground biomass for Eucalyptus trees.