A finite mixture distribution approach for characterizing tree diameter distributions by natural social class in pure even-aged Scots pine stands in Poland

Zasada, M.; Cieszewski, Chris J.

doi:10.1016/j.foreco.2003.12.023

Cited by 38 publications

(30 citation statements)

References 29 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…2G). Unfortunately, irregular uneven-aged stands are commonly seen in the forested landscape and difficulty modeling these distributions with the classic unimodal Weibull approach has been encountered by other authors (Zhang et al 2001, Liu et al 2002, Zasada and Cieszewski 2005, Zhang and Liu 2006, Maltamo et al 2007. The complexity of unevenaged stands also makes it difficult to model their growth and yield, given that stand age and site index are commonly used to assess site quality for many growth and yield models (Peng 2000).…”

Section: Discussionmentioning

confidence: 99%

“…This stratification of forest types normally results in regular and uniform diameter distributions, which can be well modeled by the 2-parameter Weibull function (Zhang and Liu 2006). Alternatively, uneven-aged stands, mixedwood stands, or old-growth stands are often characterized by multimodal or irregular diameter distributions, for which the 2-parameter Weibull distribution may be an over simplification (Zhang et al 2001, Liu et al 2002, Zasada and Cieszewski 2005, Zhang and Liu 2006 and age may be an inappropriate stratifier (Peng 2000). For these stands, a number of alternate distributions have been proposed, the most flexible being finite mixture models (Zhang and Liu 2006).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

LiDAR and Weibull modeling of diameter and basal area

Thomas¹,

Oliver²,

Lim³

et al. 2008

The Forestry Chronicle

View full text Add to dashboard Cite

This study investigates the ability to predict forest diameter distributions from light detection and ranging (LiDAR) data using Weibull modelling for forest stands in central Ontario. Results suggest that the unimodal 2-parameter Weibull model is a promising technique for the prediction of diameter class distributions, with strong relationships evident for several subgroups (at 95% confidence, r 2 adj =0.83, 0.78, 0.88, 0.80, 0.83, and 0.65, with validation RMSE of 4.09 m 2 /ha, 0.61 stems/ha, 6.05, 0.64, 4.73, and 0.09 for basal area, stem density, and the Weibull a and b parameters for basal area and stem density, respectively). The unimodal models were found to be least effective for the irregularly shaped diameter distributions, particularly for low-density coniferous plots that have undergone shelterwood treatment. A significant improvement in results for these irregular plots was found with a finite mixture modelling approach, suggesting that finite mixture models may extend our ability to predict diameter distributions over large portions of the landscape.Key words: LiDAR, Weibull, finite mixture modeling, diameter class distributions, multiple linear regression RÉSUMÉCette étude porte sur la capacité de prédiction de la distribution des diamètres d'arbres à partir de données de détection de la lumière et de calcul de la distance (LiDAR) utilisées dans un modèle Weibull pour des peuplements forestiers du centre de l'Ontario. Les résultats laissent entendre que le modèle Weibull unimodal à 2 paramètres constitue une technique prometteuse de la prédiction de la distribution des classes de diamètre comportant de fortes corrélations évidentes pour certains sous-groupes (à un niveau de confiance 95%, r 2 adj =0.83, 0.78, 0.88, 0.80, 0.83 et 0.65, une variance de 4,09 m 2 /ha, 0,61 tiges/ha, 6,05, 0,64, 4,73 et de 0,09 respectivement pour la surface terrière, le nombre de tige par hectare et pour les paramètres a et b de Weibull portant sur la surface terrière et le nombre de tige). Les modèles unimodaux se sont avérés être moins efficaces dans le cas des distributions de forme irrégulière des diamètres, particulièrement dans le cas de parcelles de faible densité de résineux ayant subi des traitements de coupe progressive. Une amélioration significative des résultats de ces parcelles irrégulières est apparue à la suite d'une approche de modélisation pour peuplement mélangé spécifique, laissant entendre que les modèles pour peuplement mélangé spécifique pourrait accroître notre capacité de prédire la distribution des diamètres pour de grandes portions de l' écosystème.Mots clés : LiDAR, Weibull, modélisation de peuplement mélangé spécifique, distributions des classes de diamètre, régression linéaire multiple

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

LiDAR and Weibull modeling of diameter and basal area

Thomas¹,

Oliver²,

Lim³

et al. 2008

The Forestry Chronicle

View full text Add to dashboard Cite

show abstract

“…The component in the mixture distribution was discussed in the plantation and two-species mixed forest stands [14,15] . The first component in the mixture of two Weibull distributions describing ES was fitted for BTS and BCTS in shape but the accuracy was worse than the single Weibull based on the RMSE and Bias.…”

Section: Discussionmentioning

confidence: 99%

“…Zhang [13] and Liu [14] were pioneers who successfully used the finite mixture model in mixed-species forest stands. Special-level diameter distributions have been developed in Scots pine and mixed spruce-fir forest stand, however, they were rarely used to deal with an uneven-aged mixed multi-species forest stand [14,15] . The objective of this study was to investigate the suitabilities of various functions such as the exponential, the Weibull function, and the finite mixture function in modeling the diameter distributions of a typical broadleaved-Korean pine mixed forest stand on the Changbai Mountains in Northeastern China.…”

Section: Introductionmentioning

confidence: 99%

Modeling diameter distribution of the broadleaved-Korean pine mixed forest on Changbai Mountains of China

Wang

Dai

et al. 2006

SCI CHINA SER E

View full text Add to dashboard Cite

The broadleaved-Korean pine mixed forest is a native vegetation in the Changbai Mountains, northeast China. The probability density functions including the normal, negative exponential, Weibull and finite mixture distribution, were used to describe the diameter distributions of the species groups and entire forest stand. There is a strong correlation between parameters and mean DBH except the shape parameters in the mixture distribution. The diameter classes of species and entire forest stand showed not negative exponential but normal and "S" distribution. The mixture function was better than normal and Weibull to describe the model distribution. The location parameter had an effect on the estimated frequency in the first diameter class, when the estimated location parameter was bigger than the lower limit of the first diameter class.

show abstract

“…Weibull, gamma) have often been used to fit empirical DBH data more or less asymmetrically with a positive skewness (Merganič and Sterba 2006;Gove et al 2008). Mixture distributions with a few components are an appropriate tool for modelling biand multimodal empirical DBH distributions (Zhang et al 2001;Zasada and Cieszewski 2005;Podlaski 2011a, b;Zasada 2013).…”

Section: Introductionmentioning

confidence: 99%

Forest modelling: the gamma shape mixture model and simulation of tree diameter distributions

Podlaski

2017

Annals of Forest Science

View full text Add to dashboard Cite

Abstract• Key message New types of distribution functions are needed to model the dynamics of stands where important age classes are represented by few trees. In this study the gamma shape mixture model and two simulation methods were used for generating tree diameter data.• Context To analyse forest dynamics, it is necessary to know distribution of the characteristics (mainly tree diameters) of trees forming particular developmental phases. In many forest inventories, the measurement of large diameter at breast height (DBH) samples is practically impossible. In this case, DBH distributions can be generated using theoretical models.• Aims The aim of this study was to assess the precision of the approximation of empirical DBH data using the gamma shape mixture (GSM) model and kernel density estimation. The strengths and weaknesses of the two simulation methods were presented and discussed.• Methods The GSM model was adopted to approximate empirical DBH data collected in 20 near-natural stands. Two simulation methods were used: (a) the procedure based on a multimodal distribution and gamma random numbers (MDGR procedure) and (b) MCMC techniques with Metropolis-Hastings sampling (MH method).• Results The GSM model precisely fitted the investigated DBH distributions. The MDGR procedure was slightly more precise than the MH method, especially in the case of the samples of 250DBHs. The level of homogeneity within the drawn DBH sets was similar for all samples.• Conclusion The GSM model is very flexible. The DBH random variates, generated with the use of analysed procedures, represented all tree generations being significant from a biological point of view.

show abstract

A finite mixture distribution approach for characterizing tree diameter distributions by natural social class in pure even-aged Scots pine stands in Poland

Cited by 38 publications

References 29 publications

LiDAR and Weibull modeling of diameter and basal area

LiDAR and Weibull modeling of diameter and basal area

Modeling diameter distribution of the broadleaved-Korean pine mixed forest on Changbai Mountains of China

Forest modelling: the gamma shape mixture model and simulation of tree diameter distributions

Contact Info

Product

Resources

About