Wzory empiryczne pierśnicowych liczb kształtu drewna użytkowego dla olszy czarnej (Alnus glutinosa (L.) Gaertn.)

The aim of the study was to develop empirical equations for predicting breast height form factors for black alder (Alnus glutinosa). Data used to develop these equations were collected from 1496 felled trees from 136 stands. One hundred and 36 stands were located in northern and southern Poland, respectively. Separate equations to predict stand form factors (F5, F18) and tree form factors (f 5, f 18) were developed. These functions estimate form factor according to tree diameter and the average stand diameter or mean height. Equations can be used to estimate stem volume u.b. to top diameter u.b. of 5 cm or 18 cm (merchantable vol.).