[en] A compatible basal area growth system was developed for single-species, even-aged Scots pine (Pinus sylvestris L.) stands in Galicia (northwestern Spain). The data used to develop the system were obtained from an inventory of 155 plots located in unthinned or lightly thinning stands and from a second inventory of 68 of these plots. The system consists of a function for predicting initial stand basal area and another for projecting stand basal area. The former is a growth function obtained by integration of a differential equation; the latter was obtained from the initialization function expressed as an algebraic difference equation. Compatibility between the two equations was ensured by estimating the projection function parameters separately, substituting their values into the initialization function, and then fitting this function to obtain the estimate of the remaining parameter. This method of proceeding gives priority to the projection function, and was selected because it was considered that the model projection would be used most frequently to estimate stand basal area from any given initial stand conditions obtained from a forest inventory. The model that provided the best results was based on the Korf 's function (with b1 as free parameter), which explained 93.5% of the variability of the stand basal area projected by the algebraic difference equation. This model estimates future stand basal area using initial basal area and initial and final ages as independent variables. The corresponding initialization equation explained 71.9% of the variability of the stand basal area at any point in time. In this case, the free parameter was expressed as a multiplicative inverse function of site index.

[es] En este trabajo se desarrolla un sistema compatible de crecimiento en &aacute;rea basim&eacute;trica para masas regulares de Pinus sylvestris L. procedentes de plantaci&oacute;n en Galicia (noroeste de Espa&ntilde;a). Para su elaboraci&oacute;n se utilizaron datos de un primer inventario de 155 parcelas localizadas en masas poco o nada aclaradas de la especie en la zona de estudio, y de un segundo inventario de 68 de dichas parcelas. El sistema consta de una ecuaci&oacute;n de inicializaci&oacute;n de &aacute;rea basim&eacute;trica y de una ecuaci&oacute;n de proyecci&oacute;n de esa misma variable. La primera es una ecuaci&oacute;n de crecimiento obtenida por integraci&oacute;n de una ecuaci&oacute;n diferencial; la segunda se obtuvo a partir de la ecuaci&oacute;n de inicializaci&oacute;n expresando &eacute;sta en forma de diferencias algebraicas. La compatibilidad entre ambas ecuaciones se asegur&oacute; estimando independientemente los par&aacute;metros de la ecuaci&oacute;n de proyecci&oacute;n y sustituy&eacute;ndolos en la de inicializaci&oacute;n, procediendo posteriormente a un ajuste de &eacute;sta para estimar el valor del par&aacute;metro no com&uacute;n. Esta alternativa dio prioridad a la ecuaci&oacute;n de proyecci&oacute;n, en detrimento de la ecuaci&oacute;n de inicializaci&oacute;n, pues se consider&oacute; que el empleo m&aacute;s habitual del sistema ser&aacute; realizar proyecciones de &aacute;rea basim&eacute;trica a partir de unos datos iniciales obtenidos tras la realizaci&oacute;n de un inventario. El modelo que mejores resultados proporcion&oacute; fue el de Korf (con el par&aacute;metro b1 libre), que explic&oacute; el 93,5% de la variabilidad total del &aacute;rea basim&eacute;trica proyectada mediante la ecuaci&oacute;n en diferencias algebraicas. Este modelo estima el &aacute;rea basim&eacute;trica futura empleando como variables independientes el &aacute;rea basim&eacute;trica inicial y las edades inicial y final de proyecci&oacute;n. La correspondiente ecuaci&oacute;n de inicializaci&oacute;n explic&oacute; el 71,9% de la variabilidad del &aacute;rea basim&eacute;trica en un determinado instante en el tiempo, y en ella el par&aacute;metro libre se relacion&oacute; de forma inversamente proporcional al &iacute;ndice de sitio.