CONICET | Buscador de Institutos y Recursos Humanos

The estimation of forest productivity is carried out using the tree volume, which is estimated directly or by usingrelationships or equations. Foresters must design methodologies that increase the precision and diminish the costsof carrying out a forest inventory. For these reasons, the objectives of this study were, first, to define new standardvolume models (total and stem) and, secondly, to analyze their behavior in comparison to traditional models (localand standard) through their statistics and residual analysis (according to site and diameter classes). Two hundredand fifty-one specimens of Nothofagus antarctica throughout Tierra del Fuego (Argentine) were used, having thediameter at breast height (DBH) 7.5-61.0 cm and total height 3.5-15.0 m. Local functions (V = ƒ (DBH)), traditionalstandard equations (V = ƒ (DBH, TH)), non-traditional standard equations (V = ƒ (DBH, site class)) and a newproposal (V = ƒ (DBH, dominant height)) were fitted. All functions gave a good fit. Total volume models presentedaverage percentage errors varying between 1.0% and 3.8%, and absolute values between 15% and 17%. Stemmodels showed average percentage errors of 1.1% to 4.1%, and absolute ones of 19% to 24%. The traditionalequations result in lower absolute error while the non-traditional volume equations have lesser average percentageerrors and show different behavior when site and diameter gradients were analyzed. If one considers the effortrequired for data capture during the forest inventory and the precision of the model for volume calculation, the nontraditionalvolume equations are the most suitable for this purpose. These avoid the necessity of measuring the totalheight of individual trees during the inventory, diminishing the costs while maintaining acceptable error levels inthe estimation of volume.

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