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Juvenile stem volume equations for planted Azadirachta excelsa in the state of Johore, Peninsular Malaysia


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


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.

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Additional Metadata

Item Type: Article
Subject: Juvenile wood
Subject: Afforestation - Environmental aspects
Subject: Sustainable forestry
Divisions: Faculty of Agriculture and Food Sciences
Publisher: Universiti Putra Malaysia Press
Keywords: Azadiractha excelsa; Height and diameter; Model evaluation; Schumacher and Hall’s Volume Equation; Spurr’s Volume Equation
Depositing User: Surimah Basri
Date Deposited: 14 Jun 2012 07:35
Last Modified: 22 Sep 2015 02:48
URI: http://psasir.upm.edu.my/id/eprint/18999
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