Efecto del método de propagación y sitio sobre atributos fustales en árboles de Pinus radiata a la edad de 17 años

The rate of establishment of radiata pine plantations in Chile has required increasing the production of plants propagated by vegetative methods. However, it is unknown whether there are differences in growth rates and stem attributes between trees propagated by seed lings or cuttings. This study quantifies differences between plant reproduction methods (seedling and cutting) and its interaction with site on stem attributes of radiata pine trees at the age of 17 years old. The evaluated attributes were stem form, location of center of volume and center of gravity and taper of bottom logs. The required information was obtained from an un-thinned and un-prunned trial located in two contrasting site conditions on volcanic ash and sandy soils. On each site, two rectangular plots (30 m × 21 m) with initial stand density of 1428 individuals per hectare that belong to the same genetic family were established. For each plot, plants propagated by seedlings or one-year-old cuttings were randomly assigned. The combination of propagation methods and sites defined a 2 × 2 factorial experiment. From each treatment, twenty trees were selected for destructive sampling. The results obtained indicate that there are no significant differences between propagation methods for stem form, form quotient, location of the center of volume and center of gravity. There were also non-significant differences between sites and there was no interaction between sites and propagation methods. However, the taper of the first log (0 m - 3 m) was significantly different between propagation methods and between sites. We concluded that trees propagated by cuttings and established in a low productivity site on sandy soils have a more cylindrical first-bottom log in comparison to trees propagated by seedlings and established in a high productivity site on volcanic ash soils located in the Andean piedmont.La tasa de plantaciones de pino radiata en Chile ha requerido aumentar la escala de producción de plantas aplicando propagación vegetativa. Sin embargo, se desconoce si existen diferencias de crecimiento y atributos fustales entre árboles reproducidos mediante semillas o estacas. Esta investigación cuantifica el efecto del método de propagación y sitio sobre atributos fustales de pino radiata a la edad de 17 años. Los atributos evaluados fueron: forma fustal, localización del centro de volumen y centro de gravedad, y ahusamiento en trozas. Los datos se obtuvieron de un ensayo silvícola sin raleo ni poda ubicado sobre suelos de ceniza volcánica y arenas. En cada sitio se establecieron dos parcelas (30 m × 21 m), considerando una densidad inicial de 1428 individuos por hectárea de la misma familia genética. Dentro de cada sitio se asignó en forma aleatoria a cada parcela, plantas propagadas por semilla o por estacas de un año de edad. La combinación de métodos de propagación y sitios definieron un diseño factorial 2 × 2. En cada tratamiento, se seleccionaron 20 individuos para muestreo destructivo. Los resultados indican que no hubo efectos significativos de los métodos de propagación para el factor y cociente de forma, centro de volumen y gravedad. Tampoco hubo efectos significativos de los sitios ni interacción entre factores. Sin embargo, el ahusamiento de la primera troza basal (0 m - 3 m) evidenció efectos significativos de ambos factores. Se puede concluir que individuos propagados por estacas y establecidos en arenas presentan trozas basales más cilíndricas que individuos establecidos en suelos derivados de cenizas volcánicas