# ABSTRACT

Carbon in the juvenile plants contribute significant share to the total carbon stock in forests. A precise estimate of aboveground biomass of the juvenile stages of trees is therefore very important. We developed a generalized allometric biomass model for the prediction of aboveground biomass of the juvenile individuals of *Rhododendron arboreum* (Sm.). We used data from 66 destructively sampled juveniles of *R. arboreum* in Gorkha district- one of the mountainous districts in Nepal, for the purpose. Using eight nonlinear functions of various forms (power, exponential, fractional forms), we evaluated several individual-level characteristics, such as size (diameter, height), crown measures (crown ratio, crown width, crown spread ratio, crown index, crown fullness ratio), height-to-diameter ratio (plant bole slenderness), number of branches, wood density, and stand-level characteristics, such as altitude and slope of sites for their potential contributions to the biomass variations of the juvenile individuals. A simple power function with cross-product of the squared-diameter and height as a main predictor and crown spread ratio as a covariate predictor showed the best fit to data (R^{2}
_{adj}=0. 90); RMSE=59.35 g) without substantial trends in the residuals. Our model is site-specific and its application should therefore be limited to those stands which were the basis of this study. Further works on recalibration, validation, and verification of our model using a larger dataset collected from a wider range of species distribution will be more interesting.

**Keywords:**

Allometric modelling; Community forest; Crown measures; Crown spread ratio; Height-to-diameter ratio