Juvenile stem volume equations for planted Azadirachta excelsa in the state of Johore, Peninsular Malaysia
Azadirachta excelsa or sentang is one of the important tree species grown in Malaysia. Equations for the predicting stem volume, from the ground to the tip for this species, are not available and hence this paper attempts to apply and examine the suitability of the existing volume equations for th...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Universiti Putra Malaysia Press
2009
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/18999/1/JTAS%20Vol%2032%20%282%29%20Aug%202009.pdf |
| _version_ | 1825946280368537600 |
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| author | Ong, Kian Huat Lim, Meng Tsai Chubo, John Keen |
| author_facet | Ong, Kian Huat Lim, Meng Tsai Chubo, John Keen |
| author_sort | Ong, Kian Huat |
| collection | UPM |
| description | Azadirachta excelsa or sentang is one of the important tree species grown in Malaysia. Equations for the
predicting stem volume, from the ground to the tip for this species, are not available and hence this paper
attempts to apply and examine the suitability of the existing volume equations for the species which can be used
by plantation growers in Malaysia. Furthermore, the performances of available volume equations in Malaysia
are seldom investigated. Evaluation is important to determine the usefulness and increase the confidence of
using a model. Three commonly used models were compared using the data derived from 36 harvested trees to
fit the equations. The addition of the weight function of 1/(d2h) was used to fit the Spurr’s combined variable
volume equation. Then, the performances of the models were evaluated based on R2, PRESS, bias and RMSE
values. The Schumacher and Hall’s equation was found to be the most appropriate for determining the total
and merchantable underbark stem volume of A. excelsa, whereas the Spurr’s equation was indicated as more
suitable to determine the merchantable overbark volume. |
| first_indexed | 2024-03-06T07:44:37Z |
| format | Article |
| id | upm.eprints-18999 |
| institution | Universiti Putra Malaysia |
| language | English |
| last_indexed | 2024-03-06T07:44:37Z |
| publishDate | 2009 |
| publisher | Universiti Putra Malaysia Press |
| record_format | dspace |
| spelling | upm.eprints-189992015-09-22T02:48:54Z http://psasir.upm.edu.my/id/eprint/18999/ Juvenile stem volume equations for planted Azadirachta excelsa in the state of Johore, Peninsular Malaysia Ong, Kian Huat Lim, Meng Tsai Chubo, John Keen Azadirachta excelsa or sentang is one of the important tree species grown in Malaysia. Equations for the predicting stem volume, from the ground to the tip for this species, are not available and hence this paper attempts to apply and examine the suitability of the existing volume equations for the species which can be used by plantation growers in Malaysia. Furthermore, the performances of available volume equations in Malaysia are seldom investigated. Evaluation is important to determine the usefulness and increase the confidence of using a model. Three commonly used models were compared using the data derived from 36 harvested trees to fit the equations. The addition of the weight function of 1/(d2h) was used to fit the Spurr’s combined variable volume equation. Then, the performances of the models were evaluated based on R2, PRESS, bias and RMSE values. The Schumacher and Hall’s equation was found to be the most appropriate for determining the total and merchantable underbark stem volume of A. excelsa, whereas the Spurr’s equation was indicated as more suitable to determine the merchantable overbark volume. Universiti Putra Malaysia Press 2009-08 Article PeerReviewed application/pdf en http://psasir.upm.edu.my/id/eprint/18999/1/JTAS%20Vol%2032%20%282%29%20Aug%202009.pdf Ong, Kian Huat and Lim, Meng Tsai and Chubo, John Keen (2009) Juvenile stem volume equations for planted Azadirachta excelsa in the state of Johore, Peninsular Malaysia. Pertanika Journal of Tropical Agricultural Science, 32 (2). pp. 133-141. ISSN 1511-3701 http://www.pertanika.upm.edu.my/Pertanika%20PAPERS/JTAS%20Vol.%2032%20(2)%20Aug.%202009/08%20Pages%20133-141.pdf Juvenile wood Afforestation - Environmental aspects Sustainable forestry |
| spellingShingle | Juvenile wood Afforestation - Environmental aspects Sustainable forestry Ong, Kian Huat Lim, Meng Tsai Chubo, John Keen Juvenile stem volume equations for planted Azadirachta excelsa in the state of Johore, Peninsular Malaysia |
| title | Juvenile stem volume equations for planted Azadirachta excelsa in the state of Johore, Peninsular Malaysia |
| title_full | Juvenile stem volume equations for planted Azadirachta excelsa in the state of Johore, Peninsular Malaysia |
| title_fullStr | Juvenile stem volume equations for planted Azadirachta excelsa in the state of Johore, Peninsular Malaysia |
| title_full_unstemmed | Juvenile stem volume equations for planted Azadirachta excelsa in the state of Johore, Peninsular Malaysia |
| title_short | Juvenile stem volume equations for planted Azadirachta excelsa in the state of Johore, Peninsular Malaysia |
| title_sort | juvenile stem volume equations for planted azadirachta excelsa in the state of johore peninsular malaysia |
| topic | Juvenile wood Afforestation - Environmental aspects Sustainable forestry |
| url | http://psasir.upm.edu.my/id/eprint/18999/1/JTAS%20Vol%2032%20%282%29%20Aug%202009.pdf |
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