Abstract
Yield prediction models were developed for plantations of Acacia mangium and Acacia auriculiformis raised under the Kerala Forestry Project in Southern Kerala, India based on the data gathered from temporary sample plots laid out in plantations in the region. The data consisted of girth at breast-height and total height of trees, collected from sample plots of size 20 m x 20 m. Yield prediction models were constructed using Schumaher functions. Height-diameter equations and site index curves were also developed along with the yield prediction models. The fitted equations had high coefficient of determination. The mean Annual Increment (MAI) of commercial volume (over-bark volume of the tree up to a lower limit of 10 cm girth over bark in m3) reached its maximum at 7 years for A. mangium. At 6 years, the MAI ranged from 25 m3 ha-1 in good sites to 14 m3 ha-1 in poor sites. In the case of A. auriculiformis, the MAI of commercial volume was only nearing its maximum at 8 years. At 6 years, the MAI ranged from 20 m3ha-1 in good sites to 7 m3ha-1 in poor sites. For A. mangium, the MAI of pulpwood volume (under-bark volume of the tree up to a lower limit of 15 cm girth under bark in m3) ranged from 19 m3 ha-1 at good sites to 10 m3 ha-1 at poor sites, while in the case of A. auriculiformis, the range of MAI of pulpwood volume was from 14 m3 ha-1 at good sites to 8 m3 ha-1 at poor sites when extrapolated at 6 years in both the cases.
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