The Effect of Crown Dimensions on Stem Profile for Dahurian Larch, Korean Spruce, and Manchurian Fir in Northeast China
Crown architecture has long been evaluated for its impact on taper modeling. However, most of the research has focused on a limited number of crown dimensions. This study examined the effect of adding several crown dimensions in improving the diameter and volume estimates of Dahurian larch, Korean s...
Main Authors: | , , |
---|---|
Format: | Article |
Language: | English |
Published: |
MDPI AG
2021-03-01
|
Series: | Forests |
Subjects: | |
Online Access: | https://www.mdpi.com/1999-4907/12/4/398 |
id |
doaj-e07d08ea527e4a0db2b2928fc73ced62 |
---|---|
record_format |
Article |
spelling |
doaj-e07d08ea527e4a0db2b2928fc73ced622021-03-28T23:01:03ZengMDPI AGForests1999-49072021-03-011239839810.3390/f12040398The Effect of Crown Dimensions on Stem Profile for Dahurian Larch, Korean Spruce, and Manchurian Fir in Northeast ChinaAmna Hussain0Muhammad Khurram Shahzad1Lichun Jiang2Key Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, Harbin 150040, ChinaKey Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, Harbin 150040, ChinaKey Laboratory of Sustainable Forest Ecosystem Management-Ministry of Education, School of Forestry, Northeast Forestry University, Harbin 150040, ChinaCrown architecture has long been evaluated for its impact on taper modeling. However, most of the research has focused on a limited number of crown dimensions. This study examined the effect of adding several crown dimensions in improving the diameter and volume estimates of Dahurian larch, Korean spruce, and Manchurian fir in northeast China. The crown dimensions included crown length, crown ratio, crown width, height to live crown base, diameter at the crown base, and crown shape. A well-known taper model of Clark et al. (1991) was fitted to the data of 276 trees from natural stands. To adjust the inherent autocorrelation in the data, we added a third-order continuous-time error structure in the model fit. Model fitting was carried out with the NLMIXED procedure (Non-linear Mixed Procedure), followed by the MODEL procedure of SAS using the generalized nonlinear least-squares method. Fit statistics and graphical assessments were used to evaluate the original and modified models. Above 98% of the total variance of <i>d</i> was explained by the models for all species. The addition of crown variables showed slight improvements for root mean square error (RMSE) values in the analyzed species. The RMSE plots indicated that the models with crown variables slightly improved the diameter and volume predictions for the species but only for the upper stem (>50%–90%). The study demonstrated that crown dimensions influence the stem taper, but the original model of Clark et al. (1991) reasonably realized that effect.https://www.mdpi.com/1999-4907/12/4/398crown dimensionsform-class segmented modelautocorrelationnonlinear mixed-effects |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Amna Hussain Muhammad Khurram Shahzad Lichun Jiang |
spellingShingle |
Amna Hussain Muhammad Khurram Shahzad Lichun Jiang The Effect of Crown Dimensions on Stem Profile for Dahurian Larch, Korean Spruce, and Manchurian Fir in Northeast China Forests crown dimensions form-class segmented model autocorrelation nonlinear mixed-effects |
author_facet |
Amna Hussain Muhammad Khurram Shahzad Lichun Jiang |
author_sort |
Amna Hussain |
title |
The Effect of Crown Dimensions on Stem Profile for Dahurian Larch, Korean Spruce, and Manchurian Fir in Northeast China |
title_short |
The Effect of Crown Dimensions on Stem Profile for Dahurian Larch, Korean Spruce, and Manchurian Fir in Northeast China |
title_full |
The Effect of Crown Dimensions on Stem Profile for Dahurian Larch, Korean Spruce, and Manchurian Fir in Northeast China |
title_fullStr |
The Effect of Crown Dimensions on Stem Profile for Dahurian Larch, Korean Spruce, and Manchurian Fir in Northeast China |
title_full_unstemmed |
The Effect of Crown Dimensions on Stem Profile for Dahurian Larch, Korean Spruce, and Manchurian Fir in Northeast China |
title_sort |
effect of crown dimensions on stem profile for dahurian larch, korean spruce, and manchurian fir in northeast china |
publisher |
MDPI AG |
series |
Forests |
issn |
1999-4907 |
publishDate |
2021-03-01 |
description |
Crown architecture has long been evaluated for its impact on taper modeling. However, most of the research has focused on a limited number of crown dimensions. This study examined the effect of adding several crown dimensions in improving the diameter and volume estimates of Dahurian larch, Korean spruce, and Manchurian fir in northeast China. The crown dimensions included crown length, crown ratio, crown width, height to live crown base, diameter at the crown base, and crown shape. A well-known taper model of Clark et al. (1991) was fitted to the data of 276 trees from natural stands. To adjust the inherent autocorrelation in the data, we added a third-order continuous-time error structure in the model fit. Model fitting was carried out with the NLMIXED procedure (Non-linear Mixed Procedure), followed by the MODEL procedure of SAS using the generalized nonlinear least-squares method. Fit statistics and graphical assessments were used to evaluate the original and modified models. Above 98% of the total variance of <i>d</i> was explained by the models for all species. The addition of crown variables showed slight improvements for root mean square error (RMSE) values in the analyzed species. The RMSE plots indicated that the models with crown variables slightly improved the diameter and volume predictions for the species but only for the upper stem (>50%–90%). The study demonstrated that crown dimensions influence the stem taper, but the original model of Clark et al. (1991) reasonably realized that effect. |
topic |
crown dimensions form-class segmented model autocorrelation nonlinear mixed-effects |
url |
https://www.mdpi.com/1999-4907/12/4/398 |
work_keys_str_mv |
AT amnahussain theeffectofcrowndimensionsonstemprofilefordahurianlarchkoreanspruceandmanchurianfirinnortheastchina AT muhammadkhurramshahzad theeffectofcrowndimensionsonstemprofilefordahurianlarchkoreanspruceandmanchurianfirinnortheastchina AT lichunjiang theeffectofcrowndimensionsonstemprofilefordahurianlarchkoreanspruceandmanchurianfirinnortheastchina AT amnahussain effectofcrowndimensionsonstemprofilefordahurianlarchkoreanspruceandmanchurianfirinnortheastchina AT muhammadkhurramshahzad effectofcrowndimensionsonstemprofilefordahurianlarchkoreanspruceandmanchurianfirinnortheastchina AT lichunjiang effectofcrowndimensionsonstemprofilefordahurianlarchkoreanspruceandmanchurianfirinnortheastchina |
_version_ |
1724199442508152832 |