Modelling height-diameter relationship for Pinus wallichiana trees for Lete and Kunjo of

H. Wagle1 and R. P. Sharma2 Quantifi cation of height-diameter relationship helps in better understanding of stand dynamics. Height-diameter models can be used as necessary inputs to growth and yield models and growth simulation systems. The researchers developed height-diameter models with 364 Blue pine (Pinus wallichiana) tree data from Lete and Kunjo Village Development Committees (VDCs) of Mustang district. Eighteen non-linear models were calibrated, among which, Weibull model described the largest proportion of height variation (R2adj = 0. 9362). Gunary and Chapman-Richards ’ models also appeared almost identical to Weibull model in terms of fi t statistics and graphical appearance. The researchers recommend Weibull model for predicting total heights of Blue pine trees for the VDCs covered by the study. Key words: Blue pine, height-diameter models, modelling, Mustang district The measurements of individual tree height and diameter are essential component of forest inventories. Tree heights are used for estimating volume, site index, growth and yield, succession and carbon budget models (Peng, 2001). Although, theoretically, height can be measured on standing trees, practically, it is expensive, tedious and time consuming due to stand conditions and land confi gurations. Therefore, with many permanent or temporary sample plot systems, diameters for all trees, but height of only a few sample trees are measured. Alternatively, indirect estimation of tree heights can be made from diameter at breast height (dbh) which can be easily and accurately measured in relatively low cost. But for this, a site-and species-specific model describing a height-diameter relationship is necessary. Height-diameter model can be developed using accurately measured heights and diameters from individual trees sampled from every stand within a forest. Height-diameter models are used to predict missing heights on the stands or permanent sampl