In this work the effect of age and location within the stem on pH and buffering capacity of radiata pine sapwood was investigated. Mature and juvenile wood samples from three different heights in the trunk were obtained from 20, 25, and 30 year-old trees. Aqueous wood extracts from the samples were used to determine the pH and buffering capacity of wood. Results show a significant effect of age and location in the tree, although a strong interaction among all factors was also detected. In general sapwood tended to be more acidic in the lower part of trees, but juvenile wood showed to be more acidic than mature wood. From both type of wood tested, juvenile wood was more sensitive to change its pH and buffering capacity with the height and age. The effect of wood pH and buffering capacity in the manufacture of wood composites is discussed and further research is recommended to determine whether the variations detected in this study can affect the curing of resins and quality of wood base composite manufactured with radiata pine wood.