Browsing by Author "Barrios Trilleras, Alonso"

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    Modelos de perfiles fustales con una estructura de error autorregresiva para plantaciones de Eucalyptus tereticornis en Colombia
    (2013) Lopéz Aguirre, Ana Milena; Barrios Trilleras, Alonso; Trincado Villagran, Guillermo; Nieto Rodríguez, Víctor Manuel
    This research evaluated the performance of fourteen stem taper models for their use in Eucalyptus tereticornis forest plantations. Three types of models were evaluated: polynomials, segmented and variable-exponent models. A sample of 130 trees collected in forest plantations with stand ages between five and twelve years-old located at the Atlantic Colombian coast was used. During the parameter estimation process a continuous time autoregressive model (CAR) was used in order to expand the error structure, reducing the effect of the autocorrelation generated by the longitudinal measurements taken along the stem. The model evaluation considered a comparison of the predictive ability respect to the prediction of upper-stem diameter, upper-stem heights, merchantable volume until a given stem-height and merchantable volume until a given stem-diameter. Measures of bias, precision and error were used for evaluating the models. A third-order continuous-time autoregressive model CAR (3) allowed to adequately model the residual autocorrelation for all stem profile models. The variable-exponent models showed the best performance in terms of goodness of fit and predictive capability
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    Modelos regionales de altura–diámetro para plantaciones jóvenes de Eucalyptus tereticornis en la costa atlántica colombiana
    (2013) Lopéz Aguirre, Ana Milena; Trincado Villagran, Guillermo; Barrios Trilleras, Alonso; Nieto Rodríguez, Víctor Manuel
    An important area of Eucalyptus tereticornis plantations has been established in the Atlantic coast in Colombia. Decision planning and estimates of future wood supply will necessary require the use of growth projection systems. Among the components of this system are models able to predict the total height of trees growing under diverse conditions of stand age, site and management. This research focused on the construction of regional height-diameter models in order to implement a growth simulator. Ten regional height-diameter models were evaluated, which had different numbers and types of predictor variables. Data required were obtained from 63 permanent sample plots established in plantations with stand ages between 2 and 8 years old and stand densities from 388 to 1,640 trees per hectare distributed in the Atlantic coast. Measurements of bias, precision and error were used for model evaluation. During the validation process no important differences among the evaluated models were detected. However, models that contained the mean height and mean diameter of the dominant trees as stand-level predictor variables showed a minor bias and error. Finally, the three-parameter regional model proposed by Krumland and Wensel was selected as the best
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    SIMFOR Versión 1.2 Simulador de crecimiento de plantaciones forestales : manual de usuario
    (2014) Lopéz Aguirre, Ana Milena; Barrios Trilleras, Alonso; Nieto Rodríguez, Víctor Manuel