Evaluation of estimation methods for fitting the three-parameter Weibull distribution to European beech forests

Bončina, Živa (author), Trifković, Vasilije (author), Rosset, Christian (author), Klopčič, Matija (author)

We evaluated three estimation methods for fitting the three-parameter Weibull distribution to even-aged European beech (Fagus sylvatica) forests by using experimental tree diameter data collected in 3709 sample plots (500 m2 each). The maximum likelihood estimation method (MLE), the method of moments (MOM) and the method of modified moments type 1 (MM1) were applied for fitting the Weibull function. The goodness-of-fit of stand parameters (total tree number, stand basal area, dominant stand diameter and mean quadratic diameter) was tested by MAE and RMSE, and the probability and cumulative density functions of trees per 5 cm diameter classes were additionally tested by the Kolmogorov-Smirnov test and compared with Kolmogorov-Smirnov’s D statistic. All three methods are suitable for estimating stand parameters based on the fitted Weibull function. Fitting the diameter distribution per 5 cm diameter classes at the plot level was less accurate due to the low number of trees or irregular diameter distribution of trees. The MM1 method was found to be the most suitable for fitting the three-parameter Weibull distribution to beech forests represented by data derived from small plots.

• Language: English
• Keywords: diameter distribution fitting, Weibull function, parameter estimation, inventory data, circular sample plots, near-natural forests, Fagus Sylvatica, Slovenia
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Publication date: 01.12.2022
• Year: 2022
• Number of pages: Str. 484-490
• Numbering: Vol. 15, iss. 6
• PID: 20.500.12556/RUL-142941
• UDC: 630*6
• ISSN on article: 1971-7458
• DOI: 10.3832/ifor4145-015
• COBISS.SI-ID: 132338691
• Publication date in RUL: 05.12.2022

Record is a part of a journal

• Title: IForest
• Shortened title: IForest
• Publisher: SISEF
• ISSN: 1971-7458
• COBISS.SI-ID: 2513830

Licences

• License: CC BY-NC 4.0, Creative Commons Attribution-NonCommercial 4.0 International
• Link: http://creativecommons.org/licenses/by-nc/4.0/
• Description: A creative commons license that bans commercial use, but the users don’t have to license their derivative works on the same terms.

Secondary language

• Language: Slovenian
• Keywords: prilagoditev porazdelitve premera, Weibullova funkcija, ocena parametrov, podatki gozdne inventure, krožne vzorčne ploskve, skoraj naravni gozdovi, Fagus Sylvatica, bukev, Slovenija