Dimensional relationships of open-grown trees in Austria

The purpose of the study is to investigate crown width, breast height diameter, height to live crown base, and taper rates of trees which were unaffected by inter tree competition throughout their life. Such open-grown trees represent the empirical maximum tree dimensions which have been used for developing management guidelines, modelling competition and crown closure. Using 435 open-grown trees including 11 different tree species from an Austria-wide open-grown tree study, equations were developed for predicting: (1) the crown width, (2) the breast height diameter, (3) the height to live crown base, and (4) the taper rates of such open-grown trees. All developed relationships were tested for possible site variations. The results indicate that except for the breast height diameter-height relationship of stone pine and the taper rates of Norway spruce and larch, site influences can be neglected because they unduly complicate empirical assumptions for a small gain in predictability. Finally, the results of this study make it possible to determine maximum tree dimensions for all tree species in Austria. (C) 1997 Elsevier Science B.V.