Diameter structure of the stands of poplar clones
R. Petráš, J. Mecko, V. Nociarhttps://doi.org/10.17221/65/2009-JFSCitation:Petráš R., Mecko J., Nociar V. (2010): Diameter structure of the stands of poplar clones. J. For. Sci., 56: 165-170.
The construction of a continuous mathematical model of frequency distributions of the diameters of trees of poplar clones Robusta and I-214 in dependence on tree diameter and mean diameter of stand is presented. Empirical material consists of diameter measurements on research plots from poplar regions in Slovakia. There were 90 plots for I-214 clone and 142 plots for Robusta clone. There were about 10–250 trees with mean diameter 2–70 cm on the research plots. The model was derived according to the three-parameter Weibull function. Its parameters were estimated by maximum likelihood method of the logarithm of the probability density function. Smoothed sample probability densities were processed in continuous mathematical models where the probability density of trees in stands is a function of their diameters and mean diameter of the stand. The method of regression smoothing of the parameters of Weibull function from sample sets in dependence on their mean diameter was used. In the whole range of mean diameters both clones have slightly left-skewed distribution with a relatively small variation range.Keywords:
diameter distribution function; frequency distributions of diameters; poplar clones; Robusta; I-214; Weibull function