Abstract

HONORATO-SALAZAR, J. Amador. Stem taper models for Acrocarpus fraxinifolius Wight & Arn. in agroforestry plantations of the Northern Range of Puebla state. Rev. mex. de cienc. forestales [online]. 2011, vol.2, n.6, pp.55-71. ISSN 2007-1132.

Acrocarpus fraxinifolius or pink cedar was introduced in 1992 to the Northern region of Puebla State in small areas as shade tree in coffee plantations. The area with this species is near 1,630 ha, which soon will be ready for harvesting. However, there is not technical information that helps with the forest management of the plantations to predict the individual tree volume and stand volume to be removed during thinning or final cuts. Therefore, the objective of this work was to develop a stem taper model for pink cedar of the agroforestry plantations in the Northern mountain region of Puebla. Twelve stem taper models were fitted to diameter-height data from 130 destructively sampled trees and six fit statistics were used for ranking the taper models. Based on the ranking value, the best six models were selected to carry out further analysis for multicollinearity, effect of autocorrelation and heteroscedasticity. The model of Thomas and Parresol was selected as the most suitable to describe the experimental data of pink cedar, because it did not show problems of multicollinearity, as indicated by the index value condition. In addition, the statistical procedure of weighted regression was applied to this model in order to account for heteroscedasticity, which improved the predictive capacity of the model. The weighted model is therefore recommended for the estimation of diameter at different height, merchantable and total volume of pink cedar stems for agroforestry plantations in the region of study.

Keywords : Acrocarpus fraxinifolius; tree taper; pink cedar; stem taper model; agroforestry plantations; total volume.

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