Rotated sigmoid structures in managed uneven-aged northern hardwood stands: a look at the Burr Type III distribution

Stand structures from a combined density manipulation and even- to uneven-aged conversion experiment on the Bartlett Experimental Forest (New Hampshire, USA) were examined 25 years after initial treatment for rotated sigmoidal diameter distributions. A comparison was made on these stands between two probability density functions for fitting these residual structures: the Burr Type III and a finite mixture of Weibulls. All stands exhibited some form of uneven-aged structure (either reverse J or rotated sigmoid) after 25 years. The Burr distribution fit the final distributions as well as the more complicated finite mixture model in all cases.