When measuring in a forest inventory, height and diameter at breast height are basic variables. Generalised models do not require measuring tree heights, and the number of measurements is minimal. However, the opinions of researchers differ in both the number of variables included in the model and in the number of parameters. The purpose of this study was to obtain 24 new generalised height-diameter models based on simple ones, compare them with 9 generalised models selected from other studies, and develop an appropriate height-diameter model for birch in the European part of Russia. The article shows that even in simple cases, there is a wide variety of options for generalised models. Moreover, models with three independent variables may be necessary and sufficient. These are the diameter at breast height, quadratic diameter at breast height, and the mean height. The performance statistics showed that modified power function is the most suitable and, therefore, it is recommended for predicting the height-diameter relationships for birch trees in this study area. The predicting variables for applying developed generalised models to estimate total tree height require less sampling effort. They derive from conventional forest inventory data which cuts costs and saves time during fieldwork.

Keywords: generalised model, height-diameter relationship, total tree height, diameter at breast height, birch stand, European Russia