Development and Validation of Height-Diameter Models for Cupressus lusitanica in Gergeda Forest, Ethiopia
This study was conducted to fit and evaluate ten existing nonlinear height diameter functions for Cupressus lusitanica in Gergeda forest Ethiopia. A total of 260 trees were measured for their diameter at breast height (D) and height using destructive sampling methods. This data were randomly split i...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Taylor & Francis Group
2018-07-01
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| Series: | Forest Science and Technology |
| Subjects: | |
| Online Access: | http://dx.doi.org/10.1080/21580103.2018.1482794 |
| _version_ | 1818298071119822848 |
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| author | Mengesha Tsega Awoke Guadie Zebene Lakew Teffera Yigez Belayneh Dongjie Niu |
| author_facet | Mengesha Tsega Awoke Guadie Zebene Lakew Teffera Yigez Belayneh Dongjie Niu |
| author_sort | Mengesha Tsega |
| collection | DOAJ |
| description | This study was conducted to fit and evaluate ten existing nonlinear height diameter functions for Cupressus lusitanica in Gergeda forest Ethiopia. A total of 260 trees were measured for their diameter at breast height (D) and height using destructive sampling methods. This data were randomly split in to two datasets for model development (50%) and for model validation (50%). Considering hetroscadasticity of variance, all functions were fitted using weighted nonlinear least square regression. To evaluate the performance of each model, five fit statistics-such as Coefficient of determination (R2), root mean square error (RMSE), bias (Ē), absolute mean deviation (AMD), and coefficient of variation (CV%) were used. Among all the models tested, the Weibull type function of the form H = 1.3 + a (1-exp (-bDc)) + ɛ was observed to give the best fit based on the model’s goodness of fit and predictive ability. Therefore, this model with three parameters has been conformed to provide reliable estimate of total tree height for Cupressus lusitanica in Gergeda forest, Ethiopia. |
| first_indexed | 2024-12-13T04:29:29Z |
| format | Article |
| id | doaj.art-2a7a99aab6314482893262d3180f8e2c |
| institution | Directory Open Access Journal |
| issn | 2158-0103 2158-0715 |
| language | English |
| last_indexed | 2024-12-13T04:29:29Z |
| publishDate | 2018-07-01 |
| publisher | Taylor & Francis Group |
| record_format | Article |
| series | Forest Science and Technology |
| spelling | doaj.art-2a7a99aab6314482893262d3180f8e2c2022-12-21T23:59:35ZengTaylor & Francis GroupForest Science and Technology2158-01032158-07152018-07-0114313814410.1080/21580103.2018.14827941482794Development and Validation of Height-Diameter Models for Cupressus lusitanica in Gergeda Forest, EthiopiaMengesha Tsega0Awoke Guadie1Zebene Lakew Teffera2Yigez Belayneh3Dongjie Niu4Tongji UniversityArba Minch UniversityTongji UniversityTongji UniversityTongji UniversityThis study was conducted to fit and evaluate ten existing nonlinear height diameter functions for Cupressus lusitanica in Gergeda forest Ethiopia. A total of 260 trees were measured for their diameter at breast height (D) and height using destructive sampling methods. This data were randomly split in to two datasets for model development (50%) and for model validation (50%). Considering hetroscadasticity of variance, all functions were fitted using weighted nonlinear least square regression. To evaluate the performance of each model, five fit statistics-such as Coefficient of determination (R2), root mean square error (RMSE), bias (Ē), absolute mean deviation (AMD), and coefficient of variation (CV%) were used. Among all the models tested, the Weibull type function of the form H = 1.3 + a (1-exp (-bDc)) + ɛ was observed to give the best fit based on the model’s goodness of fit and predictive ability. Therefore, this model with three parameters has been conformed to provide reliable estimate of total tree height for Cupressus lusitanica in Gergeda forest, Ethiopia.http://dx.doi.org/10.1080/21580103.2018.1482794Cupressus lusitanicadestructive samplinggergeda foresthetroscadasticitymodel validationweighted least square |
| spellingShingle | Mengesha Tsega Awoke Guadie Zebene Lakew Teffera Yigez Belayneh Dongjie Niu Development and Validation of Height-Diameter Models for Cupressus lusitanica in Gergeda Forest, Ethiopia Forest Science and Technology Cupressus lusitanica destructive sampling gergeda forest hetroscadasticity model validation weighted least square |
| title | Development and Validation of Height-Diameter Models for Cupressus lusitanica in Gergeda Forest, Ethiopia |
| title_full | Development and Validation of Height-Diameter Models for Cupressus lusitanica in Gergeda Forest, Ethiopia |
| title_fullStr | Development and Validation of Height-Diameter Models for Cupressus lusitanica in Gergeda Forest, Ethiopia |
| title_full_unstemmed | Development and Validation of Height-Diameter Models for Cupressus lusitanica in Gergeda Forest, Ethiopia |
| title_short | Development and Validation of Height-Diameter Models for Cupressus lusitanica in Gergeda Forest, Ethiopia |
| title_sort | development and validation of height diameter models for cupressus lusitanica in gergeda forest ethiopia |
| topic | Cupressus lusitanica destructive sampling gergeda forest hetroscadasticity model validation weighted least square |
| url | http://dx.doi.org/10.1080/21580103.2018.1482794 |
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