Compatible taper-volume models of Quercus variabilis Blume forests in north China

Zheng, Conghui; Wang, Y.; Jia, Lei; Mason, Euan G.; We, Sorlie; Sun, Caowen; Duan, Jie

doi:10.3832/ifor2114-010

Cited by 6 publications

(7 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Those types of taper models were first elaborated in British Columbia from 33 species groups (Kozak 1988), and these models are still evolving using different fitting methods (Socha et al 2020). In addition, Zheng et al (2017) indicated that variable taper equations can sometimes provide more flexible descriptions of tree profiles than simple taper equations, especially in the lower part of a stem. However, a disadvantage of variable-form taper equations is that they cannot be analytically integrated to calculate total stem or log volumes (Muhairwe 1999;Diéguez-Aranda et al 2006).…”

Section: Discussionmentioning

confidence: 99%

“…However, a disadvantage of variable-form taper equations is that they cannot be analytically integrated to calculate total stem or log volumes (Muhairwe 1999;Diéguez-Aranda et al 2006). Moreover, Zheng et al (2017) claimed that those taper models suffered from statistical complexity, resulting in difficulty in being understood and correctly used by forest managers.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Taper models for black locust in west Poland

Bronisz¹,

Zasada²

2020

Silva Fenn.

View full text Add to dashboard Cite

The diameter at any point on a stem and tree volume are some of the most important types of information used in forest management planning. One of the methods to predict the diameter at any point on a stem is to develop taper models. Black locust ( L.) occurs in almost all forests in Poland, with the largest concentration in the western part of the country. Using empirical data obtained from 13 black locust stands (48 felled trees), seven taper models with different numbers of estimated parameters were analysed for section diameters both over and under bark using fixed and mixed-effects modelling approaches. Assuming a lack of additional measurements, the best fitted taper models were used for the prediction of over bark volume using both methods. The predicted volume was compared with the results from different volume equations available for black locust. The variable-form taper model with eight estimated parameters fitted the data the best. The lowest root mean square error for volume prediction was achieved for the elaborated fixed-effects taper model (0.0476), followed by the mixed-effects taper model (0.0489). At the same time, the difference between the volume relative errors achieved based on the taper models does not differ significantly from the results obtained using the volume equations already available for black locust (two of the three analysed).Robinia pseudoacacia

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Taper models for black locust in west Poland

Bronisz¹,

Zasada²

2020

Silva Fenn.

View full text Add to dashboard Cite

show abstract

“…According to Zheng, et al [51], compatible taper-volume models are flexible tools for total and merchantable volume prediction. Those models contain a taper equation and a total volume equation.…”

Section: Discussionmentioning

confidence: 99%

Comparison of Fixed- and Mixed-Effects Approaches to Taper Modeling for Scots Pine in West Poland

Bronisz

Zasada

2019

Forests

View full text Add to dashboard Cite

Diameter measurements along the stem, which are the basis for taper models, usually have a hierarchical structure. Mixed-effects models, where fixed and random effects are distinguished, are a possible solution for this type of data. However, in order to fully absorb the potential of this method, random effects prediction, which requires additional measurements (diameter along stem), is recommended. This article presents a comparison of various fitting methods (mixed- and fixed-effects model approaches) of the variable-exponent taper model created by Kozak for determining the outside bark diameter along the stem and predicting the tree volume of Scots pine trees in west Poland. During the analysis, it was assumed that no additional measured data were available for practical use; therefore, for the mixed-effects model approach, fixed effects prediction without random effects was applied. Both fitting strategies were compared based on modeling and an independent validation data set. The comparison of mixed- and fixed-effects fitting strategies for the diameter along the stem indicated that the taper model fitted using the mixed-effects model approach better fit the data. Moreover, the error rate for the total tree volume prediction for the independent data set was lower for the mixed-effects model solution than for the fixed-effects one.

show abstract

“…An investigation of each class for each validation statistic of TPP 2 indicated that the mean prediction error of dub prediction at any given h, h prediction at any given dub, and log volume prediction at any given log length was within 0.8-2.3%, 1.5-4.8%, and 1.8-2.5%, respectively (Table 4). Importantly, the model predicted all 3 values within 1.8% in the lower bole, due to more sample points, resulting in a relatively higher accurate prediction in the lower bole, which is a more valued section of a tree (Fonweban et al, 2011;Warner et al, 2016;Zheng et al, 2017;López-Martínez et al, 2019). Overall, there was reduction in prediction accuracy for samples collected toward the top of the tree and of log volume prediction in taller trees.…”

Section: Validation Of Calibrationsmentioning

confidence: 96%

Development of a Taper Equation for Teak (Tectona grandis L.f.) Growing in Western Thailand

Choochuen

Suksavate

Meunpong

2021

Environ. Nat. Resour. J.

View full text Add to dashboard Cite

Teak is an important and valuable tropical hardwood species. In this study, we developed and evaluated suitable taper equations for teak growing in Western Thailand using a formulation of Goodwin cubic polynomial model combined with a bark thickness model. The best taper model calibration was selected based on goodness-of-fit and leave-one-out cross validation statistical testing. In total, 12 different model calibrations were tested, with Thong Pha Phum (TPP) 2 being the most suitable for teak in Western Thailand. The mean prediction error of three validation statistics: (prediction of diameter under bark given height; prediction of height given diameter under bark; and prediction of under bark volume given log length) were within 10% and the overall validation index was 5.454, which was the lowest when compared to other calibrations. A comparison of TPP 2 with a teak taper equation developed for Northern Thailand, using a graphical analysis of the stem shape and bark thickness, indicated that the teak trees growing in the two regions have similar stem shapes, but the trees in Western Thailand tend to have a thicker bark. These results will also help in further work as they indicate that bark thickness equations are particularly important.

show abstract

Compatible taper-volume models of Quercus variabilis Blume forests in north China

Cited by 6 publications

References 32 publications

Taper models for black locust in west Poland

Taper models for black locust in west Poland

Comparison of Fixed- and Mixed-Effects Approaches to Taper Modeling for Scots Pine in West Poland

Development of a Taper Equation for Teak (Tectona grandis L.f.) Growing in Western Thailand

Contact Info

Product

Resources

About