Comparison of Fixed- and Mixed-effects Approaches to Taper Modeling for Scots Pine in West Poland
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, ra...
Main Authors: | , |
---|---|
Format: | Article |
Language: | English |
Published: |
MDPI AG
2019-11-01
|
Series: | Forests |
Subjects: | |
Online Access: | https://www.mdpi.com/1999-4907/10/11/975 |
id |
doaj-e36596a1df0443a7a5a31942825b08e9 |
---|---|
record_format |
Article |
spelling |
doaj-e36596a1df0443a7a5a31942825b08e92020-11-24T21:50:05ZengMDPI AGForests1999-49072019-11-01101197510.3390/f10110975f10110975Comparison of Fixed- and Mixed-effects Approaches to Taper Modeling for Scots Pine in West PolandKarol Bronisz0Michał Zasada1Institute of Forest Sciences, Warsaw University of Life Sciences—SGGW, Nowoursynowska 159, PL 02-776 Warsaw, PolandInstitute of Forest Sciences, Warsaw University of Life Sciences—SGGW, Nowoursynowska 159, PL 02-776 Warsaw, PolandDiameter 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.https://www.mdpi.com/1999-4907/10/11/975scots pinediameter along stemvolumemixed-effects models |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Karol Bronisz Michał Zasada |
spellingShingle |
Karol Bronisz Michał Zasada Comparison of Fixed- and Mixed-effects Approaches to Taper Modeling for Scots Pine in West Poland Forests scots pine diameter along stem volume mixed-effects models |
author_facet |
Karol Bronisz Michał Zasada |
author_sort |
Karol Bronisz |
title |
Comparison of Fixed- and Mixed-effects Approaches to Taper Modeling for Scots Pine in West Poland |
title_short |
Comparison of Fixed- and Mixed-effects Approaches to Taper Modeling for Scots Pine in West Poland |
title_full |
Comparison of Fixed- and Mixed-effects Approaches to Taper Modeling for Scots Pine in West Poland |
title_fullStr |
Comparison of Fixed- and Mixed-effects Approaches to Taper Modeling for Scots Pine in West Poland |
title_full_unstemmed |
Comparison of Fixed- and Mixed-effects Approaches to Taper Modeling for Scots Pine in West Poland |
title_sort |
comparison of fixed- and mixed-effects approaches to taper modeling for scots pine in west poland |
publisher |
MDPI AG |
series |
Forests |
issn |
1999-4907 |
publishDate |
2019-11-01 |
description |
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. |
topic |
scots pine diameter along stem volume mixed-effects models |
url |
https://www.mdpi.com/1999-4907/10/11/975 |
work_keys_str_mv |
AT karolbronisz comparisonoffixedandmixedeffectsapproachestotapermodelingforscotspineinwestpoland AT michałzasada comparisonoffixedandmixedeffectsapproachestotapermodelingforscotspineinwestpoland |
_version_ |
1725885443070754816 |