The estimation of basket willow (Salix viminalis) yield - New approach, Part II: Theoretical model and its practical application

The paper presents an innovative approach to probabilistic modelling of the amount of biomass of fast-growing bushes on the example of basket willow (Salix viminalis). The model was developed on the basis of results of biometric measurements of randomly selected shoots of basket willow, cut periodically from bushes at least 0.5 m tall, cultivated on an experimental plot. The description of the random variation of willow shoot and bush was made with the use of a two-dimensional gamma distribution describing the shoot mass and volume, as well as the Pascal distribution characterising the number of shoots in a plant. The result was an estimation of the variation of plant mass under the conditions of observation of one or more shoots. The very good fit of the model to the experimental data indicates that it is justified to accept the model as a basic tool for the estimation of the amount of biomass on a plantation.