Stem taper function for Acacia hybrid trees in southeastern regio
Keywords:
Stem taper,, insidebark stem,, outsidebark stem,, stem taper function, commercial timber yieldAbstract
The tree stem taper functions are used to estimate and predict the standing stem volume and commercial timber yield. At present, silviculture and forest inventory are still lacking in stem taper and commercial timber yield functions for Acacia hybrid plantations. The objective of this study was to construct tapered functions to estimate the insidebark and outsidebark stem volume and commercial timber yield for Acacia hybrid plantations. The stem taper functions were constructed from 80 sample trees of the d iameter at breast height (DBH) from 4 - 24 cm. The appropriate stem taper functions were tested from 6 candidate functions. The applicability of the taper functions was tested from 5 trees at the diameter classes from 10 - 20 cm. The stem volume and commercial timber yield functions at the individual tree level were constructed as univariate functions; where the predictive variable is DBH. Research results show that these six functions described well the stem taper of Acacia hybrid trees at the significance level of P < 0.01. The taper function proposed by Nguyen Van Them is the most appropriate function to construct the insidebark and outsidebark stem taper functions of Acacia hybrid trees. These stem taper functions, volume and commercial timber yield functions received less than 5% error.
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