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The objectives of this work were: 1) to estimate parameters and 2) to validate 7 taper functions fitted to stem profiles of  5 commercial pine species of the El Salto, Durango region. Measurements of diameter at several stem heights were conducted in fallen trees during harvesting operations. The total number of trees measured for each species was: 507 ( Pinus cooperi ), 453 ( P. durangensis ), 424 ( P. engelmannii ), 400 ( P. leiophylla ), and 322 ( P. herrerae ) of which 75% were used to estimate parameters and the remaining 25% to test the goodness of fit of taper fuctions of Clutter (1980), Amidon (1984), Biging (1984), Kozak (1988), Kozak y Newnham (1992). Parameters were fitted by least square techniques in linear, polinomial and multiple regression analysis. The goodness of fit test consisted of comparing the statistics, coefficient of determination, standard error, and skewness, as well as, normality, randomness, and common variance of errors. The results showed that the model of Biging (1984) estimated better the stem profiles of the five pine species since it showed one of the largest coefficient of determination, one of the smallest standard errors and errors were distributed close to the normal. For this reason, this model is recommended to estimate stem profiles of the pine species of the study area. The model estimates accurately stem volume for trees with diameter smaller than 30 cm but it requires additional research to estimate merchanteable volume of trees with diameters larger than 30 cm.

Ajuste de funciones de ahusamiento a los perfiles fustales de cinco Pináceas de la región de El Salto, Durango