Biomass and volume models for clonal Eucalyptus tereticornis coppice under agroforestry systems in central India

Abstract

Eucalypt has been one of the most widely planted trees outside the forest in India including avenue and agroforestry plantations. Mostly propagated through seeds and clones, eucalypt is a good coppicer that can attain more than 2-3 times higher biomass than seedling for given period. Four-year-old Eucalyptus tereticornis coppice (ITC Bhadrachalam-clones), planted in four different spacings, were harvested to develop biomass and volume models. Out of 114 coppice plants, 84 for volume and 30 for biomass estimation were utilized. Above-ground dry biomass for individual tree was found highest in agri-silviculture system (107.71 kg tree^-1), whereas per hectare biomass (94.84 tons ha^-1) was highest in compact block plantation. Various (21) linear/non-linear functions were attempted to predict biomass/volume on the basis of DBH (D) and height (H). Prediction accuracy of double entry models (based on D²H) was slightly better than single entry models (based on DBH alone) in case of both biomass as well as volume. Quadratic model (Y=a+b*X+c*X²), where Y denotes dependent variable (biomass or volume) and X denotes independent variables (D or D²H), performed better (than the remaining tested models) in terms of estimation precision and prediction accuracy.