Models of stem taper and volume are important tools in forest management enabling estimation of log volumes, quality classification, and growth and yield forecasting. The models in current use in Norway are a combination of several models developed over the last century. In the present study models for estimating taper- and volume of tree stems, with- and without bark, were developed for Norway spruce, Scots pine, and birch using a large national dataset. From a total of eleven equations for stem taper and six equations for bark thickness, the equations suggested byKozak (1988) and Hannrup(2004) were selected for stem taper and bark thickness respectively. The fitted models can be used for predicting diameters at any point along the stem, stem- and log volume, with- and without bark.