Abstract:

Aim of study: Information about the diameter distribution of a stand is a key resource to determine planning strategies, silvicultural treatment options and product variety. In this study, the diameter distributions of Fagus orientalis Libsky stands located in Karabük region were researched, and relationship between parameters of Weibull function and stand variables was investigated. Area of study: Data used in this study were obtained from pure Oriental beech (Fagus orientalis Libsky) stands located in the Karabük region, north-central Turkey. Material and methods: For this study, sixty-two sample plots from pure Fagus orientalis Lipsky stands located in Karabük region were taken. Maximum likelihood method was used to estimate parameters of the two-parameter Weibull probability density function. The parameters estimated were then expressed as linear functions of stand variables such as mean diameter, basal area, minimum and maximum diameters etc. Main results: The regression model using arithmetic mean diameter as an independent variable and the model using maximum diameter of the stand as an independent variable were found superior for estimation of scale and shape parameters, respectively. Highlights: While the Weibull distributions determined by both methods give close results, the method of determining the distribution parameters with the developed regression models seems to be superior in terms of examining the diameter distribution changes according to different stand structure simulations.

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