“Wood quality studies are an important source of information for the assessment of the potential value of plantation grown conifers. To utilize this information fully, the reference coordinates of specimens with respect to the position in stem frequently have to be changed from ring number to distance from the pith. Investigation shows that the simpler types of exponential and polynomial equations are unsatisfactory for the prediction of stem size in terms of its age, and that a better approximation of this relationship is obtained by expressing rate of growth as a function of age and then calculating the tree size from a summation of the annual growth increments. In practice transformation can be most readily carried out by graphical methods. These methods are illustrated by an example of ring number to distance (Pinus elliottii var. elliottii Engelm) and distance to ring number transformation (Araucaria cunninghamii Ait.).” – p. [1].